check cached dynamic module first

2025-10-29 15:13:28 +00:00 · 2025-07-30 15:40:52 -07:00
369 changed files with 39945 additions and 37600 deletions
--- a/.github/actions/install/action.yml
+++ b/.github/actions/install/action.yml
@@ -5,7 +5,7 @@ inputs:
  zig:
    description: 'Zig version to install'
    required: false
-    default: '0.15.2'
+    default: '0.14.1'
  arch:
    description: 'CPU arch used to select the v8 lib'
    required: false
@@ -17,11 +17,11 @@ inputs:
  zig-v8:
    description: 'zig v8 version to install'
    required: false
-    default: 'v0.1.33'
+    default: 'v0.1.28'
  v8:
    description: 'v8 version to install'
    required: false
-    default: '14.0.365.4'
+    default: '13.6.233.8'
  cache-dir:
    description: 'cache dir to use'
    required: false
@@ -67,23 +67,9 @@ runs:
        mkdir -p v8/out/${{ inputs.os }}/release/obj/zig/
        ln -s ${{ inputs.cache-dir }}/v8/libc_v8.a v8/out/${{ inputs.os }}/release/obj/zig/libc_v8.a

-    - name: Cache libiconv
-      id: cache-libiconv
-      uses: actions/cache@v4
-      env:
-        cache-name: cache-libiconv
-      with:
-        path: ${{ inputs.cache-dir }}/libiconv
-        key: vendor/libiconv/libiconv-1.17
-
-    - name: download libiconv
-      if: ${{ steps.cache-libiconv.outputs.cache-hit != 'true' }}
+    - name: libiconv
      shell: bash
-      run: make download-libiconv
-
-    - name: build libiconv
-      shell: bash
-      run: make build-libiconv
+      run: make install-libiconv

    - name: build mimalloc
      shell: bash
--- a/.github/workflows/e2e-test.yml
+++ b/.github/workflows/e2e-test.yml
@@ -93,30 +93,9 @@ jobs:
      - name: run end to end tests
        run: |
          ./lightpanda serve & echo $! > LPD.pid
-          go run runner/main.go
+          go run runner/main.go --verbose
          kill `cat LPD.pid`

-      - name: build proxy
-        run: |
-          cd proxy
-          go build
-
-      - name: run end to end tests through proxy
-        run: |
-          ./proxy/proxy & echo $! > PROXY.id
-          ./lightpanda serve --http_proxy 'http://127.0.0.1:3000' & echo $! > LPD.pid
-          go run runner/main.go
-          kill `cat LPD.pid` `cat PROXY.id`
-
-      - name: run request interception through proxy
-        run: |
-          export PROXY_USERNAME=username PROXY_PASSWORD=password
-          ./proxy/proxy & echo $! > PROXY.id
-          ./lightpanda serve & echo $! > LPD.pid
-          URL=https://demo-browser.lightpanda.io/campfire-commerce/ node puppeteer/proxy_auth.js
-          BASE_URL=https://demo-browser.lightpanda.io/ node playwright/proxy_auth.js
-          kill `cat LPD.pid` `cat PROXY.id`
-
  cdp-and-hyperfine-bench:
    name: cdp-and-hyperfine-bench
    needs: zig-build-release
--- a/.github/workflows/wpt.yml
+++ b/.github/workflows/wpt.yml
@@ -5,7 +5,6 @@ env:
  AWS_SECRET_ACCESS_KEY: ${{ secrets.LPD_PERF_AWS_SECRET_ACCESS_KEY }}
  AWS_BUCKET: ${{ vars.LPD_PERF_AWS_BUCKET }}
  AWS_REGION: ${{ vars.LPD_PERF_AWS_REGION }}
-  LIGHTPANDA_DISABLE_TELEMETRY: true

 on:
  schedule:
--- a/.github/workflows/zig-fmt.yml
+++ b/.github/workflows/zig-fmt.yml
@@ -1,7 +1,7 @@
 name: zig-fmt

 env:
-  ZIG_VERSION: 0.15.2
+  ZIG_VERSION: 0.14.1

 on:
  pull_request:
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
+zig-cache
 /.zig-cache/
-/zig-out/
+zig-out
+/vendor/netsurf/out
+/vendor/libiconv/
 lightpanda.id
 /v8/
-/build/
-src/html5ever/target/
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,18 +1,21 @@
+[submodule "vendor/netsurf/libwapcaplet"]
+	path = vendor/netsurf/libwapcaplet
+	url = https://github.com/lightpanda-io/libwapcaplet.git/
+[submodule "vendor/netsurf/libparserutils"]
+	path = vendor/netsurf/libparserutils
+	url = https://github.com/lightpanda-io/libparserutils.git/
+[submodule "vendor/netsurf/libdom"]
+	path = vendor/netsurf/libdom
+	url = https://github.com/lightpanda-io/libdom.git/
+[submodule "vendor/netsurf/share/netsurf-buildsystem"]
+	path = vendor/netsurf/share/netsurf-buildsystem
+	url = https://source.netsurf-browser.org/buildsystem.git
+[submodule "vendor/netsurf/libhubbub"]
+	path = vendor/netsurf/libhubbub
+	url = https://github.com/lightpanda-io/libhubbub.git/
 [submodule "tests/wpt"]
 	path = tests/wpt
 	url = https://github.com/lightpanda-io/wpt
-[submodule "vendor/nghttp2"]
-	path = vendor/nghttp2
-	url = https://github.com/nghttp2/nghttp2.git
-[submodule "vendor/mbedtls"]
-	path = vendor/mbedtls
-	url = https://github.com/Mbed-TLS/mbedtls.git
-[submodule "vendor/zlib"]
-	path = vendor/zlib
-	url = https://github.com/madler/zlib.git
-[submodule "vendor/curl"]
-	path = vendor/curl
-	url = https://github.com/curl/curl.git
-[submodule "vendor/brotli"]
-	path = vendor/brotli
-	url = https://github.com/google/brotli
+[submodule "vendor/mimalloc"]
+	path = vendor/mimalloc
+	url = https://github.com/microsoft/mimalloc.git/
--- a/6
+++ b/6
@@ -1,10 +1,10 @@
 FROM debian:stable

 ARG MINISIG=0.12
-ARG ZIG=0.15.2
+ARG ZIG=0.14.1
 ARG ZIG_MINISIG=RWSGOq2NVecA2UPNdBUZykf1CCb147pkmdtYxgb3Ti+JO/wCYvhbAb/U
-ARG V8=14.0.365.4
-ARG ZIG_V8=v0.1.33
+ARG V8=13.6.233.8
+ARG ZIG_V8=v0.1.28
 ARG TARGETPLATFORM

 RUN apt-get update -yq && \
--- a/129
+++ b/129
@@ -96,16 +96,9 @@ wpt-summary:
 	@printf "\e[36mBuilding wpt...\e[0m\n"
 	@$(ZIG) build wpt -- --summary $(filter-out $@,$(MAKECMDGOALS)) || (printf "\e[33mBuild ERROR\e[0m\n"; exit 1;)

-## Test - `grep` is used to filter out the huge compile command on build
-ifeq ($(OS), macos)
+## Test
 test:
-	@script -q /dev/null sh -c 'TEST_FILTER="${F}" $(ZIG) build test -freference-trace --summary all' 2>&1 \
-		| grep --line-buffered -v "^/.*zig test -freference-trace"
-else
-test:
-	@script -qec 'TEST_FILTER="${F}" $(ZIG) build test -freference-trace --summary all' /dev/null 2>&1 \
-		| grep --line-buffered -v "^/.*zig test -freference-trace"
-endif
+	@TEST_FILTER='${F}' $(ZIG) build test -freference-trace --summary all

 ## Run demo/runner end to end tests
 end2end:
@@ -127,24 +120,126 @@ build-v8:

 # Install and build required dependencies commands
 # ------------
-.PHONY: install-html5ever install-html5ever-dev
-.PHONY: install install-dev
+.PHONY: install-submodule
+.PHONY: install-libiconv
+.PHONY: _install-netsurf install-netsurf clean-netsurf test-netsurf install-netsurf-dev
+.PHONY: install-mimalloc install-mimalloc-dev clean-mimalloc
+.PHONY: install-dev install

 ## Install and build dependencies for release
-install: install-submodule install-html5ever
+install: install-submodule install-libiconv install-netsurf install-mimalloc

 ## Install and build dependencies for dev
-install-dev: install-submodule install-html5ever-dev
+install-dev: install-submodule install-libiconv install-netsurf-dev install-mimalloc-dev

-install-html5ever:
-	cd src/html5ever && cargo build --release --target-dir ../../build/html5ever/
+install-netsurf-dev: _install-netsurf
+install-netsurf-dev: OPTCFLAGS := -O0 -g -DNDEBUG

-install-html5ever-dev:
-	cd src/html5ever && cargo build --target-dir ../../build/html5ever/
+install-netsurf: _install-netsurf
+install-netsurf: OPTCFLAGS := -DNDEBUG
+
+BC_NS := $(BC)vendor/netsurf/out/$(OS)-$(ARCH)
+ICONV := $(BC)vendor/libiconv/out/$(OS)-$(ARCH)
+# TODO: add Linux iconv path (I guess it depends on the distro)
+# TODO: this way of linking libiconv is not ideal. We should have a more generic way
+# and stick to a specif version. Maybe build from source. Anyway not now.
+_install-netsurf: clean-netsurf
+	@printf "\e[36mInstalling NetSurf...\e[0m\n" && \
+	ls $(ICONV)/lib/libiconv.a 1> /dev/null || (printf "\e[33mERROR: you need to execute 'make install-libiconv'\e[0m\n"; exit 1;) && \
+	mkdir -p $(BC_NS) && \
+	cp -R vendor/netsurf/share $(BC_NS) && \
+	export PREFIX=$(BC_NS) && \
+	export OPTLDFLAGS="-L$(ICONV)/lib" && \
+	export OPTCFLAGS="$(OPTCFLAGS) -I$(ICONV)/include" && \
+	printf "\e[33mInstalling libwapcaplet...\e[0m\n" && \
+	cd vendor/netsurf/libwapcaplet && \
+	BUILDDIR=$(BC_NS)/build/libwapcaplet make install && \
+	cd ../libparserutils && \
+	printf "\e[33mInstalling libparserutils...\e[0m\n" && \
+	BUILDDIR=$(BC_NS)/build/libparserutils make install && \
+	cd ../libhubbub && \
+	printf "\e[33mInstalling libhubbub...\e[0m\n" && \
+	BUILDDIR=$(BC_NS)/build/libhubbub make install && \
+	rm src/treebuilder/autogenerated-element-type.c && \
+	cd ../libdom && \
+	printf "\e[33mInstalling libdom...\e[0m\n" && \
+	BUILDDIR=$(BC_NS)/build/libdom make install && \
+	printf "\e[33mRunning libdom example...\e[0m\n" && \
+	cd examples && \
+	$(ZIG) cc \
+	-I$(ICONV)/include \
+	-I$(BC_NS)/include \
+	-L$(ICONV)/lib \
+	-L$(BC_NS)/lib \
+	-liconv \
+	-ldom \
+	-lhubbub \
+	-lparserutils \
+	-lwapcaplet \
+	-o a.out \
+	dom-structure-dump.c \
+	$(ICONV)/lib/libiconv.a && \
+	./a.out > /dev/null && \
+	rm a.out && \
+	printf "\e[36mDone NetSurf $(OS)\e[0m\n"
+
+clean-netsurf:
+	@printf "\e[36mCleaning NetSurf build...\e[0m\n" && \
+	rm -Rf $(BC_NS)
+
+test-netsurf:
+	@printf "\e[36mTesting NetSurf...\e[0m\n" && \
+	export PREFIX=$(BC_NS) && \
+	export LDFLAGS="-L$(ICONV)/lib -L$(BC_NS)/lib" && \
+	export CFLAGS="-I$(ICONV)/include -I$(BC_NS)/include" && \
+	cd vendor/netsurf/libdom && \
+	BUILDDIR=$(BC_NS)/build/libdom make test
+
+download-libiconv:
+ifeq ("$(wildcard vendor/libiconv/libiconv-1.17)","")
+	@mkdir -p vendor/libiconv
+	@cd vendor/libiconv && \
+	curl https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.17.tar.gz | tar -xvzf -
+endif
+
+install-libiconv: download-libiconv clean-libiconv
+	@cd vendor/libiconv/libiconv-1.17 && \
+	./configure --prefix=$(ICONV) --enable-static && \
+	make && make install
+
+clean-libiconv:
+ifneq ("$(wildcard vendor/libiconv/libiconv-1.17/Makefile)","")
+	@cd vendor/libiconv/libiconv-1.17 && \
+	make clean
+endif

 data:
 	cd src/data && go run public_suffix_list_gen.go > public_suffix_list.zig

+.PHONY: _build_mimalloc
+
+MIMALLOC := $(BC)vendor/mimalloc/out/$(OS)-$(ARCH)
+_build_mimalloc: clean-mimalloc
+	@mkdir -p $(MIMALLOC)/build && \
+	cd $(MIMALLOC)/build && \
+	cmake -DMI_BUILD_SHARED=OFF -DMI_BUILD_OBJECT=OFF -DMI_BUILD_TESTS=OFF -DMI_OVERRIDE=OFF $(OPTS) ../../.. && \
+	make && \
+	mkdir -p $(MIMALLOC)/lib
+
+install-mimalloc-dev: _build_mimalloc
+install-mimalloc-dev: OPTS=-DCMAKE_BUILD_TYPE=Debug
+install-mimalloc-dev:
+	@cd $(MIMALLOC) && \
+	mv build/libmimalloc-debug.a lib/libmimalloc.a
+
+install-mimalloc: _build_mimalloc
+install-mimalloc:
+	@cd $(MIMALLOC) && \
+	mv build/libmimalloc.a lib/libmimalloc.a
+
+clean-mimalloc:
+	@rm -Rf $(MIMALLOC)/build
+
 ## Init and update git submodule
 install-submodule:
 	@git submodule init && \
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ Due to the nature of Playwright, a script that works with the current version of

 ## Quick start

-### Install
+### Install 
 **Install from the nightly builds**

 You can download the last binary from the [nightly
@@ -71,8 +71,9 @@ Lightpanda provides [official Docker
 images](https://hub.docker.com/r/lightpanda/browser) for both Linux amd64 and
 arm64 architectures.
 The following command fetches the Docker image and starts a new container exposing Lightpanda's CDP server on port `9222`.
+The `--privileged` option is required because the browser requires `io_uring` syscalls which are blocked by default by Docker.
 ```console
-docker run -d --name lightpanda -p 9222:9222 lightpanda/browser:nightly
+docker run -d --name lightpanda -p 9222:9222 --privileged lightpanda/browser:nightly
 ```

 ### Dump a URL
@@ -140,7 +141,8 @@ You may still encounter errors or crashes. Please open an issue with specifics i

 Here are the key features we have implemented:

- [x] HTTP loader (based on Libcurl)
+- [x] HTTP loader
+- [x] HTTP loader
 - [x] HTML parser and DOM tree (based on Netsurf libs)
 - [x] Javascript support (v8)
 - [x] DOM APIs
@@ -153,8 +155,8 @@ Here are the key features we have implemented:
 - [x] Input form
 - [x] Cookies
 - [x] Custom HTTP headers
- [x] Proxy support
- [x] Network interception
+- [ ] Proxy support
+- [ ] Network interception 

 NOTE: There are hundreds of Web APIs. Developing a browser (even just for headless mode) is a huge task. Coverage will increase over time.

@@ -164,12 +166,11 @@ You can also follow the progress of our Javascript support in our dedicated [zig

 ### Prerequisites

-Lightpanda is written with [Zig](https://ziglang.org/) `0.15.2`. You have to
+Lightpanda is written with [Zig](https://ziglang.org/) `0.14.1`. You have to
 install it with the right version in order to build the project.

 Lightpanda also depends on
 [zig-js-runtime](https://github.com/lightpanda-io/zig-js-runtime/) (with v8),
-[Libcurl](https://curl.se/libcurl/),
 [Netsurf libs](https://www.netsurf-browser.org/) and
 [Mimalloc](https://microsoft.github.io/mimalloc).

--- a/build.zig
+++ b/build.zig
@@ -19,13 +19,11 @@
 const std = @import("std");
 const builtin = @import("builtin");

-const Build = std.Build;
-
 /// Do not rename this constant. It is scanned by some scripts to determine
 /// which zig version to install.
-const recommended_zig_version = "0.15.2";
+const recommended_zig_version = "0.14.1";

-pub fn build(b: *Build) !void {
+pub fn build(b: *std.Build) !void {
    switch (comptime builtin.zig_version.order(std.SemanticVersion.parse(recommended_zig_version) catch unreachable)) {
        .eq => {},
        .lt => {
@@ -49,95 +47,32 @@ pub fn build(b: *Build) !void {
    const target = b.standardTargetOptions(.{});
    const optimize = b.standardOptimizeOption(.{});

-    const enable_tsan = b.option(bool, "tsan", "Enable Thread Sanitizer");
-    const enable_csan = b.option(std.zig.SanitizeC, "csan", "Enable C Sanitizers");
-
-    const lightpanda_module = blk: {
-        const mod = b.addModule("lightpanda", .{
-            .root_source_file = b.path("src/lightpanda.zig"),
-            .target = target,
-            .optimize = optimize,
-            .link_libc = true,
-            .link_libcpp = true,
-            .sanitize_c = enable_csan,
-            .sanitize_thread = enable_tsan,
-        });
-
-        try addDependencies(b, mod, opts);
-
-        if (optimize == .ReleaseFast or optimize == .ReleaseSmall) {
-            mod.addLibraryPath(b.path("build/html5ever/release"));
-        } else {
-            mod.addLibraryPath(b.path("build/html5ever/debug"));
-        }
-        mod.linkSystemLibrary("litefetch_html5ever", .{});
-
-        break :blk mod;
-    };
-
    {
        // browser
+        // -------
+
+        // compile and install
        const exe = b.addExecutable(.{
            .name = "lightpanda",
-            .use_llvm = true,
-            .root_module = b.createModule(.{
-                .root_source_file = b.path("src/main.zig"),
-                .target = target,
-                .optimize = optimize,
-                .sanitize_c = enable_csan,
-                .sanitize_thread = enable_tsan,
-                .imports = &.{
-                  .{.name = "lightpanda", .module = lightpanda_module},
-                },
-            }),
+            .target = target,
+            .optimize = optimize,
+            .root_source_file = b.path("src/main.zig"),
        });
+
+        try common(b, opts, exe);
        b.installArtifact(exe);

+        // run
        const run_cmd = b.addRunArtifact(exe);
        if (b.args) |args| {
            run_cmd.addArgs(args);
        }
+
+        // step
        const run_step = b.step("run", "Run the app");
        run_step.dependOn(&run_cmd.step);
    }

-    {
-        // test
-        const tests = b.addTest(.{
-            .root_module = lightpanda_module,
-            .test_runner = .{ .path = b.path("src/test_runner.zig"), .mode = .simple },
-        });
-        const run_tests = b.addRunArtifact(tests);
-        const test_step = b.step("test", "Run unit tests");
-        test_step.dependOn(&run_tests.step);
-    }
-
-    {
-        // wpt
-        const exe = b.addExecutable(.{
-            .name = "lightpanda-wpt",
-            .use_llvm = true,
-            .root_module = b.createModule(.{
-                .root_source_file = b.path("src/main_wpt.zig"),
-                .target = target,
-                .optimize = optimize,
-                .sanitize_c = enable_csan,
-                .sanitize_thread = enable_tsan,
-                .imports = &.{
-                  .{.name = "lightpanda", .module = lightpanda_module},
-                },
-            }),
-        });
-        b.installArtifact(exe);
-
-        const run_cmd = b.addRunArtifact(exe);
-        if (b.args) |args| {
-            run_cmd.addArgs(args);
-        }
-        const run_step = b.step("wpt", "Run WPT tests");
-        run_step.dependOn(&run_cmd.step);
-    }
-
    {
        // get v8
        // -------
@@ -155,18 +90,63 @@ pub fn build(b: *Build) !void {
        const build_step = b.step("build-v8", "Build v8");
        build_step.dependOn(&build_v8.step);
    }
+
+    {
+        // tests
+        // ----
+
+        // compile
+        const tests = b.addTest(.{
+            .root_source_file = b.path("src/main.zig"),
+            .test_runner = .{ .path = b.path("src/test_runner.zig"), .mode = .simple },
+            .target = target,
+            .optimize = optimize,
+        });
+        try common(b, opts, tests);
+
+        const run_tests = b.addRunArtifact(tests);
+        if (b.args) |args| {
+            run_tests.addArgs(args);
+        }
+
+        // step
+        const tests_step = b.step("test", "Run unit tests");
+        tests_step.dependOn(&run_tests.step);
+    }
+
+    {
+        // wpt
+        // -----
+
+        // compile and install
+        const wpt = b.addExecutable(.{
+            .name = "lightpanda-wpt",
+            .root_source_file = b.path("src/main_wpt.zig"),
+            .target = target,
+            .optimize = optimize,
+        });
+        try common(b, opts, wpt);
+
+        // run
+        const wpt_cmd = b.addRunArtifact(wpt);
+        if (b.args) |args| {
+            wpt_cmd.addArgs(args);
+        }
+        // step
+        const wpt_step = b.step("wpt", "WPT tests");
+        wpt_step.dependOn(&wpt_cmd.step);
+    }
 }

-fn addDependencies(b: *Build, mod: *Build.Module, opts: *Build.Step.Options) !void {
-    mod.addImport("build_config", opts.createModule());
-
+fn common(b: *std.Build, opts: *std.Build.Step.Options, step: *std.Build.Step.Compile) !void {
+    const mod = step.root_module;
    const target = mod.resolved_target.?;
-    const dep_opts = .{
-        .target = target,
-        .optimize = mod.optimize.?,
-    };
+    const optimize = mod.optimize.?;
+    const dep_opts = .{ .target = target, .optimize = optimize };

-    mod.addIncludePath(b.path("vendor/lightpanda"));
+    try moduleNetSurf(b, step, target);
+    mod.addImport("tls", b.dependency("tls", dep_opts).module("tls"));
+    mod.addImport("tigerbeetle-io", b.dependency("tigerbeetle_io", .{}).module("tigerbeetle_io"));

    {
        // v8
@@ -176,7 +156,11 @@ fn addDependencies(b: *Build, mod: *Build.Module, opts: *Build.Step.Options) !vo
        const v8_mod = b.dependency("v8", dep_opts).module("v8");
        v8_mod.addOptions("default_exports", v8_opts);
        mod.addImport("v8", v8_mod);
+    }

+    mod.link_libcpp = true;
+
+    {
        const release_dir = if (mod.optimize.? == .Debug) "debug" else "release";
        const os = switch (target.result.os.tag) {
            .linux => "linux",
@@ -197,603 +181,72 @@ fn addDependencies(b: *Build, mod: *Build.Module, opts: *Build.Step.Options) !vo
            );
        };
        mod.addObjectFile(mod.owner.path(lib_path));
-
-        switch (target.result.os.tag) {
-            .macos => {
-                // v8 has a dependency, abseil-cpp, which, on Mac, uses CoreFoundation
-                mod.addSystemFrameworkPath(.{ .cwd_relative = "/System/Library/Frameworks" });
-                mod.linkFramework("CoreFoundation", .{});
-            },
-            else => {},
-        }
    }

+    switch (target.result.os.tag) {
+        .macos => {
+            // v8 has a dependency, abseil-cpp, which, on Mac, uses CoreFoundation
+            mod.addSystemFrameworkPath(.{ .cwd_relative = "/System/Library/Frameworks" });
+            mod.linkFramework("CoreFoundation", .{});
+        },
+        else => {},
+    }
+
+    mod.addImport("build_config", opts.createModule());
+}
+
+fn moduleNetSurf(b: *std.Build, step: *std.Build.Step.Compile, target: std.Build.ResolvedTarget) !void {
+    const os = target.result.os.tag;
+    const arch = target.result.cpu.arch;
+
+    // iconv
+    const libiconv_lib_path = try std.fmt.allocPrint(
+        b.allocator,
+        "vendor/libiconv/out/{s}-{s}/lib/libiconv.a",
+        .{ @tagName(os), @tagName(arch) },
+    );
+    const libiconv_include_path = try std.fmt.allocPrint(
+        b.allocator,
+        "vendor/libiconv/out/{s}-{s}/lib/libiconv.a",
+        .{ @tagName(os), @tagName(arch) },
+    );
+    step.addObjectFile(b.path(libiconv_lib_path));
+    step.addIncludePath(b.path(libiconv_include_path));
+
    {
-        //curl
-        {
-            const is_linux = target.result.os.tag == .linux;
-            if (is_linux) {
-                mod.addCMacro("HAVE_LINUX_TCP_H", "1");
-                mod.addCMacro("HAVE_MSG_NOSIGNAL", "1");
-                mod.addCMacro("HAVE_GETHOSTBYNAME_R", "1");
-            }
-            mod.addCMacro("_FILE_OFFSET_BITS", "64");
-            mod.addCMacro("BUILDING_LIBCURL", "1");
-            mod.addCMacro("CURL_DISABLE_AWS", "1");
-            mod.addCMacro("CURL_DISABLE_DICT", "1");
-            mod.addCMacro("CURL_DISABLE_DOH", "1");
-            mod.addCMacro("CURL_DISABLE_FILE", "1");
-            mod.addCMacro("CURL_DISABLE_FTP", "1");
-            mod.addCMacro("CURL_DISABLE_GOPHER", "1");
-            mod.addCMacro("CURL_DISABLE_KERBEROS", "1");
-            mod.addCMacro("CURL_DISABLE_IMAP", "1");
-            mod.addCMacro("CURL_DISABLE_IPFS", "1");
-            mod.addCMacro("CURL_DISABLE_LDAP", "1");
-            mod.addCMacro("CURL_DISABLE_LDAPS", "1");
-            mod.addCMacro("CURL_DISABLE_MQTT", "1");
-            mod.addCMacro("CURL_DISABLE_NTLM", "1");
-            mod.addCMacro("CURL_DISABLE_PROGRESS_METER", "1");
-            mod.addCMacro("CURL_DISABLE_POP3", "1");
-            mod.addCMacro("CURL_DISABLE_RTSP", "1");
-            mod.addCMacro("CURL_DISABLE_SMB", "1");
-            mod.addCMacro("CURL_DISABLE_SMTP", "1");
-            mod.addCMacro("CURL_DISABLE_TELNET", "1");
-            mod.addCMacro("CURL_DISABLE_TFTP", "1");
-            mod.addCMacro("CURL_EXTERN_SYMBOL", "__attribute__ ((__visibility__ (\"default\"))");
-            mod.addCMacro("CURL_OS", if (is_linux) "\"Linux\"" else "\"mac\"");
-            mod.addCMacro("CURL_STATICLIB", "1");
-            mod.addCMacro("ENABLE_IPV6", "1");
-            mod.addCMacro("HAVE_ALARM", "1");
-            mod.addCMacro("HAVE_ALLOCA_H", "1");
-            mod.addCMacro("HAVE_ARPA_INET_H", "1");
-            mod.addCMacro("HAVE_ARPA_TFTP_H", "1");
-            mod.addCMacro("HAVE_ASSERT_H", "1");
-            mod.addCMacro("HAVE_BASENAME", "1");
-            mod.addCMacro("HAVE_BOOL_T", "1");
-            mod.addCMacro("HAVE_BROTLI", "1");
-            mod.addCMacro("HAVE_BUILTIN_AVAILABLE", "1");
-            mod.addCMacro("HAVE_CLOCK_GETTIME_MONOTONIC", "1");
-            mod.addCMacro("HAVE_DLFCN_H", "1");
-            mod.addCMacro("HAVE_ERRNO_H", "1");
-            mod.addCMacro("HAVE_FCNTL", "1");
-            mod.addCMacro("HAVE_FCNTL_H", "1");
-            mod.addCMacro("HAVE_FCNTL_O_NONBLOCK", "1");
-            mod.addCMacro("HAVE_FREEADDRINFO", "1");
-            mod.addCMacro("HAVE_FSETXATTR", "1");
-            mod.addCMacro("HAVE_FSETXATTR_5", "1");
-            mod.addCMacro("HAVE_FTRUNCATE", "1");
-            mod.addCMacro("HAVE_GETADDRINFO", "1");
-            mod.addCMacro("HAVE_GETEUID", "1");
-            mod.addCMacro("HAVE_GETHOSTBYNAME", "1");
-            mod.addCMacro("HAVE_GETHOSTBYNAME_R_6", "1");
-            mod.addCMacro("HAVE_GETHOSTNAME", "1");
-            mod.addCMacro("HAVE_GETPEERNAME", "1");
-            mod.addCMacro("HAVE_GETPPID", "1");
-            mod.addCMacro("HAVE_GETPPID", "1");
-            mod.addCMacro("HAVE_GETPROTOBYNAME", "1");
-            mod.addCMacro("HAVE_GETPWUID", "1");
-            mod.addCMacro("HAVE_GETPWUID_R", "1");
-            mod.addCMacro("HAVE_GETRLIMIT", "1");
-            mod.addCMacro("HAVE_GETSOCKNAME", "1");
-            mod.addCMacro("HAVE_GETTIMEOFDAY", "1");
-            mod.addCMacro("HAVE_GMTIME_R", "1");
-            mod.addCMacro("HAVE_IDN2_H", "1");
-            mod.addCMacro("HAVE_IF_NAMETOINDEX", "1");
-            mod.addCMacro("HAVE_IFADDRS_H", "1");
-            mod.addCMacro("HAVE_INET_ADDR", "1");
-            mod.addCMacro("HAVE_INET_PTON", "1");
-            mod.addCMacro("HAVE_INTTYPES_H", "1");
-            mod.addCMacro("HAVE_IOCTL", "1");
-            mod.addCMacro("HAVE_IOCTL_FIONBIO", "1");
-            mod.addCMacro("HAVE_IOCTL_SIOCGIFADDR", "1");
-            mod.addCMacro("HAVE_LDAP_URL_PARSE", "1");
-            mod.addCMacro("HAVE_LIBGEN_H", "1");
-            mod.addCMacro("HAVE_LIBZ", "1");
-            mod.addCMacro("HAVE_LL", "1");
-            mod.addCMacro("HAVE_LOCALE_H", "1");
-            mod.addCMacro("HAVE_LOCALTIME_R", "1");
-            mod.addCMacro("HAVE_LONGLONG", "1");
-            mod.addCMacro("HAVE_MALLOC_H", "1");
-            mod.addCMacro("HAVE_MEMORY_H", "1");
-            mod.addCMacro("HAVE_NET_IF_H", "1");
-            mod.addCMacro("HAVE_NETDB_H", "1");
-            mod.addCMacro("HAVE_NETINET_IN_H", "1");
-            mod.addCMacro("HAVE_NETINET_TCP_H", "1");
-            mod.addCMacro("HAVE_PIPE", "1");
-            mod.addCMacro("HAVE_POLL", "1");
-            mod.addCMacro("HAVE_POLL_FINE", "1");
-            mod.addCMacro("HAVE_POLL_H", "1");
-            mod.addCMacro("HAVE_POSIX_STRERROR_R", "1");
-            mod.addCMacro("HAVE_PTHREAD_H", "1");
-            mod.addCMacro("HAVE_PWD_H", "1");
-            mod.addCMacro("HAVE_RECV", "1");
-            mod.addCMacro("HAVE_SA_FAMILY_T", "1");
-            mod.addCMacro("HAVE_SELECT", "1");
-            mod.addCMacro("HAVE_SEND", "1");
-            mod.addCMacro("HAVE_SETJMP_H", "1");
-            mod.addCMacro("HAVE_SETLOCALE", "1");
-            mod.addCMacro("HAVE_SETRLIMIT", "1");
-            mod.addCMacro("HAVE_SETSOCKOPT", "1");
-            mod.addCMacro("HAVE_SIGACTION", "1");
-            mod.addCMacro("HAVE_SIGINTERRUPT", "1");
-            mod.addCMacro("HAVE_SIGNAL", "1");
-            mod.addCMacro("HAVE_SIGNAL_H", "1");
-            mod.addCMacro("HAVE_SIGSETJMP", "1");
-            mod.addCMacro("HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID", "1");
-            mod.addCMacro("HAVE_SOCKET", "1");
-            mod.addCMacro("HAVE_STDBOOL_H", "1");
-            mod.addCMacro("HAVE_STDINT_H", "1");
-            mod.addCMacro("HAVE_STDIO_H", "1");
-            mod.addCMacro("HAVE_STDLIB_H", "1");
-            mod.addCMacro("HAVE_STRCASECMP", "1");
-            mod.addCMacro("HAVE_STRDUP", "1");
-            mod.addCMacro("HAVE_STRERROR_R", "1");
-            mod.addCMacro("HAVE_STRING_H", "1");
-            mod.addCMacro("HAVE_STRINGS_H", "1");
-            mod.addCMacro("HAVE_STRSTR", "1");
-            mod.addCMacro("HAVE_STRTOK_R", "1");
-            mod.addCMacro("HAVE_STRTOLL", "1");
-            mod.addCMacro("HAVE_STRUCT_SOCKADDR_STORAGE", "1");
-            mod.addCMacro("HAVE_STRUCT_TIMEVAL", "1");
-            mod.addCMacro("HAVE_SYS_IOCTL_H", "1");
-            mod.addCMacro("HAVE_SYS_PARAM_H", "1");
-            mod.addCMacro("HAVE_SYS_POLL_H", "1");
-            mod.addCMacro("HAVE_SYS_RESOURCE_H", "1");
-            mod.addCMacro("HAVE_SYS_SELECT_H", "1");
-            mod.addCMacro("HAVE_SYS_SOCKET_H", "1");
-            mod.addCMacro("HAVE_SYS_STAT_H", "1");
-            mod.addCMacro("HAVE_SYS_TIME_H", "1");
-            mod.addCMacro("HAVE_SYS_TYPES_H", "1");
-            mod.addCMacro("HAVE_SYS_UIO_H", "1");
-            mod.addCMacro("HAVE_SYS_UN_H", "1");
-            mod.addCMacro("HAVE_TERMIO_H", "1");
-            mod.addCMacro("HAVE_TERMIOS_H", "1");
-            mod.addCMacro("HAVE_TIME_H", "1");
-            mod.addCMacro("HAVE_UNAME", "1");
-            mod.addCMacro("HAVE_UNISTD_H", "1");
-            mod.addCMacro("HAVE_UTIME", "1");
-            mod.addCMacro("HAVE_UTIME_H", "1");
-            mod.addCMacro("HAVE_UTIMES", "1");
-            mod.addCMacro("HAVE_VARIADIC_MACROS_C99", "1");
-            mod.addCMacro("HAVE_VARIADIC_MACROS_GCC", "1");
-            mod.addCMacro("HAVE_ZLIB_H", "1");
-            mod.addCMacro("RANDOM_FILE", "\"/dev/urandom\"");
-            mod.addCMacro("RECV_TYPE_ARG1", "int");
-            mod.addCMacro("RECV_TYPE_ARG2", "void *");
-            mod.addCMacro("RECV_TYPE_ARG3", "size_t");
-            mod.addCMacro("RECV_TYPE_ARG4", "int");
-            mod.addCMacro("RECV_TYPE_RETV", "ssize_t");
-            mod.addCMacro("SEND_QUAL_ARG2", "const");
-            mod.addCMacro("SEND_TYPE_ARG1", "int");
-            mod.addCMacro("SEND_TYPE_ARG2", "void *");
-            mod.addCMacro("SEND_TYPE_ARG3", "size_t");
-            mod.addCMacro("SEND_TYPE_ARG4", "int");
-            mod.addCMacro("SEND_TYPE_RETV", "ssize_t");
-            mod.addCMacro("SIZEOF_CURL_OFF_T", "8");
-            mod.addCMacro("SIZEOF_INT", "4");
-            mod.addCMacro("SIZEOF_LONG", "8");
-            mod.addCMacro("SIZEOF_OFF_T", "8");
-            mod.addCMacro("SIZEOF_SHORT", "2");
-            mod.addCMacro("SIZEOF_SIZE_T", "8");
-            mod.addCMacro("SIZEOF_TIME_T", "8");
-            mod.addCMacro("STDC_HEADERS", "1");
-            mod.addCMacro("TIME_WITH_SYS_TIME", "1");
-            mod.addCMacro("USE_NGHTTP2", "1");
-            mod.addCMacro("USE_MBEDTLS", "1");
-            mod.addCMacro("USE_THREADS_POSIX", "1");
-            mod.addCMacro("USE_UNIX_SOCKETS", "1");
-        }
+        // mimalloc
+        const mimalloc = "vendor/mimalloc";
+        const lib_path = try std.fmt.allocPrint(
+            b.allocator,
+            mimalloc ++ "/out/{s}-{s}/lib/libmimalloc.a",
+            .{ @tagName(os), @tagName(arch) },
+        );
+        step.addObjectFile(b.path(lib_path));
+        step.addIncludePath(b.path(mimalloc ++ "/include"));
+    }

-        try buildZlib(b, mod);
-        try buildBrotli(b, mod);
-        try buildMbedtls(b, mod);
-        try buildNghttp2(b, mod);
-        try buildCurl(b, mod);
+    // netsurf libs
+    const ns = "vendor/netsurf";
+    const ns_include_path = try std.fmt.allocPrint(
+        b.allocator,
+        ns ++ "/out/{s}-{s}/include",
+        .{ @tagName(os), @tagName(arch) },
+    );
+    step.addIncludePath(b.path(ns_include_path));

-        switch (target.result.os.tag) {
-            .macos => {
-                // needed for proxying on mac
-                mod.addSystemFrameworkPath(.{ .cwd_relative = "/System/Library/Frameworks" });
-                mod.linkFramework("CoreFoundation", .{});
-                mod.linkFramework("SystemConfiguration", .{});
-            },
-            else => {},
-        }
+    const libs: [4][]const u8 = .{
+        "libdom",
+        "libhubbub",
+        "libparserutils",
+        "libwapcaplet",
+    };
+    inline for (libs) |lib| {
+        const ns_lib_path = try std.fmt.allocPrint(
+            b.allocator,
+            ns ++ "/out/{s}-{s}/lib/" ++ lib ++ ".a",
+            .{ @tagName(os), @tagName(arch) },
+        );
+        step.addObjectFile(b.path(ns_lib_path));
+        step.addIncludePath(b.path(ns ++ "/" ++ lib ++ "/src"));
    }
 }
-
-fn buildZlib(b: *Build, m: *Build.Module) !void {
-    const zlib = b.addLibrary(.{
-        .name = "zlib",
-        .root_module = m,
-    });
-
-    const root = "vendor/zlib/";
-    zlib.installHeader(b.path(root ++ "zlib.h"), "zlib.h");
-    zlib.installHeader(b.path(root ++ "zconf.h"), "zconf.h");
-    zlib.addCSourceFiles(.{ .flags = &.{
-        "-DHAVE_SYS_TYPES_H",
-        "-DHAVE_STDINT_H",
-        "-DHAVE_STDDEF_H",
-    }, .files = &.{
-        root ++ "adler32.c",
-        root ++ "compress.c",
-        root ++ "crc32.c",
-        root ++ "deflate.c",
-        root ++ "gzclose.c",
-        root ++ "gzlib.c",
-        root ++ "gzread.c",
-        root ++ "gzwrite.c",
-        root ++ "inflate.c",
-        root ++ "infback.c",
-        root ++ "inftrees.c",
-        root ++ "inffast.c",
-        root ++ "trees.c",
-        root ++ "uncompr.c",
-        root ++ "zutil.c",
-    } });
-}
-
-fn buildBrotli(b: *Build, m: *Build.Module) !void {
-    const brotli = b.addLibrary(.{
-        .name = "brotli",
-        .root_module = m,
-    });
-
-    const root = "vendor/brotli/c/";
-    brotli.addIncludePath(b.path(root ++ "include"));
-    brotli.addCSourceFiles(.{ .flags = &.{}, .files = &.{
-        root ++ "common/constants.c",
-        root ++ "common/context.c",
-        root ++ "common/dictionary.c",
-        root ++ "common/platform.c",
-        root ++ "common/shared_dictionary.c",
-        root ++ "common/transform.c",
-        root ++ "dec/bit_reader.c",
-        root ++ "dec/decode.c",
-        root ++ "dec/huffman.c",
-        root ++ "dec/prefix.c",
-        root ++ "dec/state.c",
-        root ++ "dec/static_init.c",
-    } });
-}
-
-fn buildMbedtls(b: *Build, m: *Build.Module) !void {
-    const mbedtls = b.addLibrary(.{
-        .name = "mbedtls",
-        .root_module = m,
-    });
-
-    const root = "vendor/mbedtls/";
-    mbedtls.addIncludePath(b.path(root ++ "include"));
-    mbedtls.addIncludePath(b.path(root ++ "library"));
-
-    mbedtls.addCSourceFiles(.{ .flags = &.{}, .files = &.{
-        root ++ "library/aes.c",
-        root ++ "library/aesni.c",
-        root ++ "library/aesce.c",
-        root ++ "library/aria.c",
-        root ++ "library/asn1parse.c",
-        root ++ "library/asn1write.c",
-        root ++ "library/base64.c",
-        root ++ "library/bignum.c",
-        root ++ "library/bignum_core.c",
-        root ++ "library/bignum_mod.c",
-        root ++ "library/bignum_mod_raw.c",
-        root ++ "library/camellia.c",
-        root ++ "library/ccm.c",
-        root ++ "library/chacha20.c",
-        root ++ "library/chachapoly.c",
-        root ++ "library/cipher.c",
-        root ++ "library/cipher_wrap.c",
-        root ++ "library/constant_time.c",
-        root ++ "library/cmac.c",
-        root ++ "library/ctr_drbg.c",
-        root ++ "library/des.c",
-        root ++ "library/dhm.c",
-        root ++ "library/ecdh.c",
-        root ++ "library/ecdsa.c",
-        root ++ "library/ecjpake.c",
-        root ++ "library/ecp.c",
-        root ++ "library/ecp_curves.c",
-        root ++ "library/entropy.c",
-        root ++ "library/entropy_poll.c",
-        root ++ "library/error.c",
-        root ++ "library/gcm.c",
-        root ++ "library/hkdf.c",
-        root ++ "library/hmac_drbg.c",
-        root ++ "library/lmots.c",
-        root ++ "library/lms.c",
-        root ++ "library/md.c",
-        root ++ "library/md5.c",
-        root ++ "library/memory_buffer_alloc.c",
-        root ++ "library/nist_kw.c",
-        root ++ "library/oid.c",
-        root ++ "library/padlock.c",
-        root ++ "library/pem.c",
-        root ++ "library/pk.c",
-        root ++ "library/pk_ecc.c",
-        root ++ "library/pk_wrap.c",
-        root ++ "library/pkcs12.c",
-        root ++ "library/pkcs5.c",
-        root ++ "library/pkparse.c",
-        root ++ "library/pkwrite.c",
-        root ++ "library/platform.c",
-        root ++ "library/platform_util.c",
-        root ++ "library/poly1305.c",
-        root ++ "library/psa_crypto.c",
-        root ++ "library/psa_crypto_aead.c",
-        root ++ "library/psa_crypto_cipher.c",
-        root ++ "library/psa_crypto_client.c",
-        root ++ "library/psa_crypto_ffdh.c",
-        root ++ "library/psa_crypto_driver_wrappers_no_static.c",
-        root ++ "library/psa_crypto_ecp.c",
-        root ++ "library/psa_crypto_hash.c",
-        root ++ "library/psa_crypto_mac.c",
-        root ++ "library/psa_crypto_pake.c",
-        root ++ "library/psa_crypto_rsa.c",
-        root ++ "library/psa_crypto_se.c",
-        root ++ "library/psa_crypto_slot_management.c",
-        root ++ "library/psa_crypto_storage.c",
-        root ++ "library/psa_its_file.c",
-        root ++ "library/psa_util.c",
-        root ++ "library/ripemd160.c",
-        root ++ "library/rsa.c",
-        root ++ "library/rsa_alt_helpers.c",
-        root ++ "library/sha1.c",
-        root ++ "library/sha3.c",
-        root ++ "library/sha256.c",
-        root ++ "library/sha512.c",
-        root ++ "library/threading.c",
-        root ++ "library/timing.c",
-        root ++ "library/version.c",
-        root ++ "library/version_features.c",
-        root ++ "library/pkcs7.c",
-        root ++ "library/x509.c",
-        root ++ "library/x509_create.c",
-        root ++ "library/x509_crl.c",
-        root ++ "library/x509_crt.c",
-        root ++ "library/x509_csr.c",
-        root ++ "library/x509write.c",
-        root ++ "library/x509write_crt.c",
-        root ++ "library/x509write_csr.c",
-        root ++ "library/debug.c",
-        root ++ "library/mps_reader.c",
-        root ++ "library/mps_trace.c",
-        root ++ "library/net_sockets.c",
-        root ++ "library/ssl_cache.c",
-        root ++ "library/ssl_ciphersuites.c",
-        root ++ "library/ssl_client.c",
-        root ++ "library/ssl_cookie.c",
-        root ++ "library/ssl_debug_helpers_generated.c",
-        root ++ "library/ssl_msg.c",
-        root ++ "library/ssl_ticket.c",
-        root ++ "library/ssl_tls.c",
-        root ++ "library/ssl_tls12_client.c",
-        root ++ "library/ssl_tls12_server.c",
-        root ++ "library/ssl_tls13_keys.c",
-        root ++ "library/ssl_tls13_server.c",
-        root ++ "library/ssl_tls13_client.c",
-        root ++ "library/ssl_tls13_generic.c",
-    } });
-}
-
-fn buildNghttp2(b: *Build, m: *Build.Module) !void {
-    const nghttp2 = b.addLibrary(.{
-        .name = "nghttp2",
-        .root_module = m,
-    });
-
-    const root = "vendor/nghttp2/";
-    nghttp2.addIncludePath(b.path(root ++ "lib"));
-    nghttp2.addIncludePath(b.path(root ++ "lib/includes"));
-    nghttp2.addCSourceFiles(.{ .flags = &.{
-        "-DNGHTTP2_STATICLIB",
-        "-DHAVE_NETINET_IN",
-        "-DHAVE_TIME_H",
-    }, .files = &.{
-        root ++ "lib/sfparse.c",
-        root ++ "lib/nghttp2_alpn.c",
-        root ++ "lib/nghttp2_buf.c",
-        root ++ "lib/nghttp2_callbacks.c",
-        root ++ "lib/nghttp2_debug.c",
-        root ++ "lib/nghttp2_extpri.c",
-        root ++ "lib/nghttp2_frame.c",
-        root ++ "lib/nghttp2_hd.c",
-        root ++ "lib/nghttp2_hd_huffman.c",
-        root ++ "lib/nghttp2_hd_huffman_data.c",
-        root ++ "lib/nghttp2_helper.c",
-        root ++ "lib/nghttp2_http.c",
-        root ++ "lib/nghttp2_map.c",
-        root ++ "lib/nghttp2_mem.c",
-        root ++ "lib/nghttp2_option.c",
-        root ++ "lib/nghttp2_outbound_item.c",
-        root ++ "lib/nghttp2_pq.c",
-        root ++ "lib/nghttp2_priority_spec.c",
-        root ++ "lib/nghttp2_queue.c",
-        root ++ "lib/nghttp2_rcbuf.c",
-        root ++ "lib/nghttp2_session.c",
-        root ++ "lib/nghttp2_stream.c",
-        root ++ "lib/nghttp2_submit.c",
-        root ++ "lib/nghttp2_version.c",
-        root ++ "lib/nghttp2_ratelim.c",
-        root ++ "lib/nghttp2_time.c",
-    } });
-}
-
-fn buildCurl(b: *Build, m: *Build.Module) !void {
-    const curl = b.addLibrary(.{
-        .name = "curl",
-        .root_module = m,
-    });
-
-    const root = "vendor/curl/";
-
-    curl.addIncludePath(b.path(root ++ "lib"));
-    curl.addIncludePath(b.path(root ++ "include"));
-    curl.addCSourceFiles(.{
-        .flags = &.{},
-        .files = &.{
-            root ++ "lib/altsvc.c",
-            root ++ "lib/amigaos.c",
-            root ++ "lib/asyn-ares.c",
-            root ++ "lib/asyn-base.c",
-            root ++ "lib/asyn-thrdd.c",
-            root ++ "lib/bufq.c",
-            root ++ "lib/bufref.c",
-            root ++ "lib/cf-h1-proxy.c",
-            root ++ "lib/cf-h2-proxy.c",
-            root ++ "lib/cf-haproxy.c",
-            root ++ "lib/cf-https-connect.c",
-            root ++ "lib/cf-socket.c",
-            root ++ "lib/cfilters.c",
-            root ++ "lib/conncache.c",
-            root ++ "lib/connect.c",
-            root ++ "lib/content_encoding.c",
-            root ++ "lib/cookie.c",
-            root ++ "lib/cshutdn.c",
-            root ++ "lib/curl_addrinfo.c",
-            root ++ "lib/curl_des.c",
-            root ++ "lib/curl_endian.c",
-            root ++ "lib/curl_fnmatch.c",
-            root ++ "lib/curl_get_line.c",
-            root ++ "lib/curl_gethostname.c",
-            root ++ "lib/curl_gssapi.c",
-            root ++ "lib/curl_memrchr.c",
-            root ++ "lib/curl_ntlm_core.c",
-            root ++ "lib/curl_range.c",
-            root ++ "lib/curl_rtmp.c",
-            root ++ "lib/curl_sasl.c",
-            root ++ "lib/curl_sha512_256.c",
-            root ++ "lib/curl_sspi.c",
-            root ++ "lib/curl_threads.c",
-            root ++ "lib/curl_trc.c",
-            root ++ "lib/cw-out.c",
-            root ++ "lib/cw-pause.c",
-            root ++ "lib/dict.c",
-            root ++ "lib/doh.c",
-            root ++ "lib/dynhds.c",
-            root ++ "lib/easy.c",
-            root ++ "lib/easygetopt.c",
-            root ++ "lib/easyoptions.c",
-            root ++ "lib/escape.c",
-            root ++ "lib/fake_addrinfo.c",
-            root ++ "lib/file.c",
-            root ++ "lib/fileinfo.c",
-            root ++ "lib/fopen.c",
-            root ++ "lib/formdata.c",
-            root ++ "lib/ftp.c",
-            root ++ "lib/ftplistparser.c",
-            root ++ "lib/getenv.c",
-            root ++ "lib/getinfo.c",
-            root ++ "lib/gopher.c",
-            root ++ "lib/hash.c",
-            root ++ "lib/headers.c",
-            root ++ "lib/hmac.c",
-            root ++ "lib/hostip.c",
-            root ++ "lib/hostip4.c",
-            root ++ "lib/hostip6.c",
-            root ++ "lib/hsts.c",
-            root ++ "lib/http.c",
-            root ++ "lib/http1.c",
-            root ++ "lib/http2.c",
-            root ++ "lib/http_aws_sigv4.c",
-            root ++ "lib/http_chunks.c",
-            root ++ "lib/http_digest.c",
-            root ++ "lib/http_negotiate.c",
-            root ++ "lib/http_ntlm.c",
-            root ++ "lib/http_proxy.c",
-            root ++ "lib/httpsrr.c",
-            root ++ "lib/idn.c",
-            root ++ "lib/if2ip.c",
-            root ++ "lib/imap.c",
-            root ++ "lib/krb5.c",
-            root ++ "lib/ldap.c",
-            root ++ "lib/llist.c",
-            root ++ "lib/macos.c",
-            root ++ "lib/md4.c",
-            root ++ "lib/md5.c",
-            root ++ "lib/memdebug.c",
-            root ++ "lib/mime.c",
-            root ++ "lib/mprintf.c",
-            root ++ "lib/mqtt.c",
-            root ++ "lib/multi.c",
-            root ++ "lib/multi_ev.c",
-            root ++ "lib/netrc.c",
-            root ++ "lib/noproxy.c",
-            root ++ "lib/openldap.c",
-            root ++ "lib/parsedate.c",
-            root ++ "lib/pingpong.c",
-            root ++ "lib/pop3.c",
-            root ++ "lib/progress.c",
-            root ++ "lib/psl.c",
-            root ++ "lib/rand.c",
-            root ++ "lib/rename.c",
-            root ++ "lib/request.c",
-            root ++ "lib/rtsp.c",
-            root ++ "lib/select.c",
-            root ++ "lib/sendf.c",
-            root ++ "lib/setopt.c",
-            root ++ "lib/sha256.c",
-            root ++ "lib/share.c",
-            root ++ "lib/slist.c",
-            root ++ "lib/smb.c",
-            root ++ "lib/smtp.c",
-            root ++ "lib/socketpair.c",
-            root ++ "lib/socks.c",
-            root ++ "lib/socks_gssapi.c",
-            root ++ "lib/socks_sspi.c",
-            root ++ "lib/speedcheck.c",
-            root ++ "lib/splay.c",
-            root ++ "lib/strcase.c",
-            root ++ "lib/strdup.c",
-            root ++ "lib/strequal.c",
-            root ++ "lib/strerror.c",
-            root ++ "lib/system_win32.c",
-            root ++ "lib/telnet.c",
-            root ++ "lib/tftp.c",
-            root ++ "lib/transfer.c",
-            root ++ "lib/uint-bset.c",
-            root ++ "lib/uint-hash.c",
-            root ++ "lib/uint-spbset.c",
-            root ++ "lib/uint-table.c",
-            root ++ "lib/url.c",
-            root ++ "lib/urlapi.c",
-            root ++ "lib/version.c",
-            root ++ "lib/ws.c",
-            root ++ "lib/curlx/base64.c",
-            root ++ "lib/curlx/dynbuf.c",
-            root ++ "lib/curlx/inet_ntop.c",
-            root ++ "lib/curlx/nonblock.c",
-            root ++ "lib/curlx/strparse.c",
-            root ++ "lib/curlx/timediff.c",
-            root ++ "lib/curlx/timeval.c",
-            root ++ "lib/curlx/wait.c",
-            root ++ "lib/curlx/warnless.c",
-            root ++ "lib/vquic/curl_ngtcp2.c",
-            root ++ "lib/vquic/curl_osslq.c",
-            root ++ "lib/vquic/curl_quiche.c",
-            root ++ "lib/vquic/vquic.c",
-            root ++ "lib/vquic/vquic-tls.c",
-            root ++ "lib/vauth/cleartext.c",
-            root ++ "lib/vauth/cram.c",
-            root ++ "lib/vauth/digest.c",
-            root ++ "lib/vauth/digest_sspi.c",
-            root ++ "lib/vauth/gsasl.c",
-            root ++ "lib/vauth/krb5_gssapi.c",
-            root ++ "lib/vauth/krb5_sspi.c",
-            root ++ "lib/vauth/ntlm.c",
-            root ++ "lib/vauth/ntlm_sspi.c",
-            root ++ "lib/vauth/oauth2.c",
-            root ++ "lib/vauth/spnego_gssapi.c",
-            root ++ "lib/vauth/spnego_sspi.c",
-            root ++ "lib/vauth/vauth.c",
-            root ++ "lib/vtls/cipher_suite.c",
-            root ++ "lib/vtls/mbedtls.c",
-            root ++ "lib/vtls/mbedtls_threadlock.c",
-            root ++ "lib/vtls/vtls.c",
-            root ++ "lib/vtls/vtls_scache.c",
-            root ++ "lib/vtls/x509asn1.c",
-        },
-    });
-}
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -4,10 +4,19 @@
    .version = "0.0.0",
    .fingerprint = 0xda130f3af836cea0,
    .dependencies = .{
-        .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/305bb3706716d32d59b2ffa674731556caa1002b.tar.gz",
-            .hash = "v8-0.0.0-xddH63bVAwBSEobaUok9J0er1FqsvEujCDDVy6ItqKQ5",
+        .tls = .{
+            .url = "https://github.com/ianic/tls.zig/archive/55845f755d9e2e821458ea55693f85c737cd0c7a.tar.gz",
+            .hash = "tls-0.1.0-ER2e0m43BQAshi8ixj1qf3w2u2lqKtXtkrxUJ4AGZDcl",
        },
-        //.v8 = .{ .path = "../zig-v8-fork" }
+        .tigerbeetle_io = .{
+            .url = "https://github.com/lightpanda-io/tigerbeetle-io/archive/61d9652f1a957b7f4db723ea6aa0ce9635e840ce.tar.gz",
+            .hash = "tigerbeetle_io-0.0.0-ViLgxpyRBAB5BMfIcj3KMXfbJzwARs9uSl8aRy2OXULd",
+        },
+        .v8 = .{
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/b22911e02e4884a76acf52aa9aff2ba169d05b40.tar.gz",
+            .hash = "v8-0.0.0-xddH69zCAwAzm1u5cQVa-uG5ib2y6PpENXCl8yEYdUYk",
+        },
+        //.v8 = .{ .path = "../zig-v8-fork" },
+        //.tigerbeetle_io = .{ .path = "../tigerbeetle-io" },
    },
 }
--- a/flake.lock
+++ b/flake.lock
@@ -1,21 +1,5 @@
 {
  "nodes": {
-    "flake-compat": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1696426674,
-        "narHash": "sha256-kvjfFW7WAETZlt09AgDn1MrtKzP7t90Vf7vypd3OL1U=",
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "rev": "0f9255e01c2351cc7d116c072cb317785dd33b33",
-        "type": "github"
-      },
-      "original": {
-        "owner": "edolstra",
-        "repo": "flake-compat",
-        "type": "github"
-      }
-    },
    "flake-utils": {
      "inputs": {
        "systems": "systems"
@@ -34,52 +18,13 @@
        "type": "github"
      }
    },
-    "flake-utils_2": {
-      "inputs": {
-        "systems": "systems_2"
-      },
-      "locked": {
-        "lastModified": 1705309234,
-        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "gitignore": {
-      "inputs": {
-        "nixpkgs": [
-          "zlsPkg",
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1709087332,
-        "narHash": "sha256-HG2cCnktfHsKV0s4XW83gU3F57gaTljL9KNSuG6bnQs=",
-        "owner": "hercules-ci",
-        "repo": "gitignore.nix",
-        "rev": "637db329424fd7e46cf4185293b9cc8c88c95394",
-        "type": "github"
-      },
-      "original": {
-        "owner": "hercules-ci",
-        "repo": "gitignore.nix",
-        "type": "github"
-      }
-    },
    "nixpkgs": {
      "locked": {
-        "lastModified": 1756822655,
-        "narHash": "sha256-xQAk8xLy7srAkR5NMZFsQFioL02iTHuuEIs3ohGpgdk=",
+        "lastModified": 1748964450,
+        "narHash": "sha256-ZouDiXkUk8mkMnah10QcoQ9Nu6UW6AFAHLScS3En6aI=",
        "owner": "nixos",
        "repo": "nixpkgs",
-        "rev": "4bdac60bfe32c41103ae500ddf894c258291dd61",
+        "rev": "9ff500cd9e123f46c55855eca64beccead29b152",
        "type": "github"
      },
      "original": {
@@ -92,9 +37,7 @@
    "root": {
      "inputs": {
        "flake-utils": "flake-utils",
-        "nixpkgs": "nixpkgs",
-        "zigPkgs": "zigPkgs",
-        "zlsPkg": "zlsPkg"
+        "nixpkgs": "nixpkgs"
      }
    },
    "systems": {
@@ -111,68 +54,6 @@
        "repo": "default",
        "type": "github"
      }
-    },
-    "systems_2": {
-      "locked": {
-        "lastModified": 1681028828,
-        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
-        "owner": "nix-systems",
-        "repo": "default",
-        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-systems",
-        "repo": "default",
-        "type": "github"
-      }
-    },
-    "zigPkgs": {
-      "inputs": {
-        "flake-compat": "flake-compat",
-        "flake-utils": "flake-utils_2",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1756555914,
-        "narHash": "sha256-7yoSPIVEuL+3Wzf6e7NHuW3zmruHizRrYhGerjRHTLI=",
-        "owner": "mitchellh",
-        "repo": "zig-overlay",
-        "rev": "d0df3a2fd0f11134409d6d5ea0e510e5e477f7d6",
-        "type": "github"
-      },
-      "original": {
-        "owner": "mitchellh",
-        "repo": "zig-overlay",
-        "type": "github"
-      }
-    },
-    "zlsPkg": {
-      "inputs": {
-        "gitignore": "gitignore",
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "zig-overlay": [
-          "zigPkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1756048867,
-        "narHash": "sha256-GFzSHUljcxy7sM1PaabbkQUdUnLwpherekPWJFxXtnk=",
-        "owner": "zigtools",
-        "repo": "zls",
-        "rev": "ce6c8f02c78e622421cfc2405c67c5222819ec03",
-        "type": "github"
-      },
-      "original": {
-        "owner": "zigtools",
-        "ref": "0.15.0",
-        "repo": "zls",
-        "type": "github"
-      }
    }
  },
  "root": "root",
--- a/flake.nix
+++ b/flake.nix
@@ -3,37 +3,20 @@

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/release-25.05";
-
-    zigPkgs.url = "github:mitchellh/zig-overlay";
-    zigPkgs.inputs.nixpkgs.follows = "nixpkgs";
-
-    zlsPkg.url = "github:zigtools/zls/0.15.0";
-    zlsPkg.inputs.zig-overlay.follows = "zigPkgs";
-    zlsPkg.inputs.nixpkgs.follows = "nixpkgs";
-
    flake-utils.url = "github:numtide/flake-utils";
  };

  outputs =
    {
      nixpkgs,
-      zigPkgs,
-      zlsPkg,
      flake-utils,
      ...
    }:
    flake-utils.lib.eachDefaultSystem (
      system:
      let
-        overlays = [
-          (final: prev: {
-            zigpkgs = zigPkgs.packages.${prev.system};
-            zls = zlsPkg.packages.${prev.system}.default;
-          })
-        ];
-
        pkgs = import nixpkgs {
-          inherit system overlays;
+          inherit system;
        };

        # We need crtbeginS.o for building.
@@ -49,7 +32,7 @@
          targetPkgs =
            pkgs: with pkgs; [
              # Build Tools
-              zigpkgs."0.15.2"
+              zig
              zls
              python3
              pkg-config
@@ -66,7 +49,6 @@
              glib.dev
              glibc.dev
              zlib
-              zlib.dev
            ];
        };
      in
--- a/src/App.zig
+++ b/src/App.zig
@@ -1,109 +0,0 @@
-const std = @import("std");
-
-const Allocator = std.mem.Allocator;
-
-const log = @import("log.zig");
-const Http = @import("http/Http.zig");
-const Platform = @import("browser/js/Platform.zig");
-
-const Notification = @import("Notification.zig");
-const Telemetry = @import("telemetry/telemetry.zig").Telemetry;
-
-// Container for global state / objects that various parts of the system
-// might need.
-const App = @This();
-
-http: Http,
-config: Config,
-platform: Platform,
-telemetry: Telemetry,
-allocator: Allocator,
-app_dir_path: ?[]const u8,
-notification: *Notification,
-
-pub const RunMode = enum {
-    help,
-    fetch,
-    serve,
-    version,
-};
-
-pub const Config = struct {
-    run_mode: RunMode,
-    tls_verify_host: bool = true,
-    http_proxy: ?[:0]const u8 = null,
-    proxy_bearer_token: ?[:0]const u8 = null,
-    http_timeout_ms: ?u31 = null,
-    http_connect_timeout_ms: ?u31 = null,
-    http_max_host_open: ?u8 = null,
-    http_max_concurrent: ?u8 = null,
-    user_agent: [:0]const u8,
-};
-
-pub fn init(allocator: Allocator, config: Config) !*App {
-    const app = try allocator.create(App);
-    errdefer allocator.destroy(app);
-
-    app.config = config;
-    app.allocator = allocator;
-
-    app.notification = try Notification.init(allocator, null);
-    errdefer app.notification.deinit();
-
-    app.http = try Http.init(allocator, .{
-        .max_host_open = config.http_max_host_open orelse 4,
-        .max_concurrent = config.http_max_concurrent orelse 10,
-        .timeout_ms = config.http_timeout_ms orelse 5000,
-        .connect_timeout_ms = config.http_connect_timeout_ms orelse 0,
-        .http_proxy = config.http_proxy,
-        .tls_verify_host = config.tls_verify_host,
-        .proxy_bearer_token = config.proxy_bearer_token,
-        .user_agent = config.user_agent,
-    });
-    errdefer app.http.deinit();
-
-    app.platform = try Platform.init();
-    errdefer app.platform.deinit();
-
-    app.app_dir_path = getAndMakeAppDir(allocator);
-
-    app.telemetry = try Telemetry.init(app, config.run_mode);
-    errdefer app.telemetry.deinit();
-
-    try app.telemetry.register(app.notification);
-
-    return app;
-}
-
-pub fn deinit(self: *App) void {
-    const allocator = self.allocator;
-    if (self.app_dir_path) |app_dir_path| {
-        allocator.free(app_dir_path);
-    }
-    self.telemetry.deinit();
-    self.notification.deinit();
-    self.http.deinit();
-    self.platform.deinit();
-
-    allocator.destroy(self);
-}
-
-fn getAndMakeAppDir(allocator: Allocator) ?[]const u8 {
-    if (@import("builtin").is_test) {
-        return allocator.dupe(u8, "/tmp") catch unreachable;
-    }
-    const app_dir_path = std.fs.getAppDataDir(allocator, "lightpanda") catch |err| {
-        log.warn(.app, "get data dir", .{ .err = err });
-        return null;
-    };
-
-    std.fs.cwd().makePath(app_dir_path) catch |err| switch (err) {
-        error.PathAlreadyExists => return app_dir_path,
-        else => {
-            allocator.free(app_dir_path);
-            log.warn(.app, "create data dir", .{ .err = err, .path = app_dir_path });
-            return null;
-        },
-    };
-    return app_dir_path;
-}
--- a/src/Notification.zig
+++ b/src/Notification.zig
@@ -1,386 +0,0 @@
-const std = @import("std");
-
-const log = @import("log.zig");
-const Page = @import("browser/Page.zig");
-const Transfer = @import("http/Client.zig").Transfer;
-
-const Allocator = std.mem.Allocator;
-
-const List = std.DoublyLinkedList;
-
-// Allows code to register for and emit events.
-// Keeps two lists
-// 1 - for a given event type, a linked list of all the listeners
-// 2 - for a given listener, a list of all it's registration
-// The 2nd one is so that a listener can unregister all of it's listeners
-// (there's currently no need for a listener to unregister only 1 or more
-// specific listener).
-//
-// Scoping is important. Imagine we created a global singleton registry, and our
-// CDP code registers for the "network_bytes_sent" event, because it needs to
-// send messages to the client when this happens. Our HTTP client could then
-// emit a "network_bytes_sent" message. It would be easy, and it would work.
-// That is, it would work until the Telemetry code makes an HTTP request, and
-// because everything's just one big global, that gets picked up by the
-// registered CDP listener, and the telemetry network activity gets sent to the
-// CDP client.
-//
-// To avoid this, one way or another, we need scoping. We could still have
-// a global registry but every "register" and every "emit" has some type of
-// "scope". This would have a run-time cost and still require some coordination
-// between components to share a common scope.
-//
-// Instead, the approach that we take is to have a notification instance per
-// scope. This makes some things harder, but we only plan on having 2
-// notification instances  at a given time: one in a Browser and one in the App.
-// What about something like Telemetry, which lives outside of a Browser but
-// still cares about Browser-events (like .page_navigate)? When the Browser
-// notification is created, a `notification_created` event is raised in the
-// App's notification, which Telemetry is registered for. This allows Telemetry
-// to register for events in the Browser notification. See the Telemetry's
-// register function.
-const Notification = @This();
-// Every event type (which are hard-coded), has a list of Listeners.
-// When the event happens, we dispatch to those listener.
-event_listeners: EventListeners,
-
-// list of listeners for a specified receiver
-// @intFromPtr(receiver) -> [listener1, listener2, ...]
-// Used when `unregisterAll` is called.
-listeners: std.AutoHashMapUnmanaged(usize, std.ArrayListUnmanaged(*Listener)),
-
-allocator: Allocator,
-mem_pool: std.heap.MemoryPool(Listener),
-
-const EventListeners = struct {
-    page_remove: List = .{},
-    page_created: List = .{},
-    page_navigate: List = .{},
-    page_navigated: List = .{},
-    page_network_idle: List = .{},
-    page_network_almost_idle: List = .{},
-    http_request_fail: List = .{},
-    http_request_start: List = .{},
-    http_request_intercept: List = .{},
-    http_request_done: List = .{},
-    http_request_auth_required: List = .{},
-    http_response_data: List = .{},
-    http_response_header_done: List = .{},
-    notification_created: List = .{},
-};
-
-const Events = union(enum) {
-    page_remove: PageRemove,
-    page_created: *Page,
-    page_navigate: *const PageNavigate,
-    page_navigated: *const PageNavigated,
-    page_network_idle: *const PageNetworkIdle,
-    page_network_almost_idle: *const PageNetworkAlmostIdle,
-    http_request_fail: *const RequestFail,
-    http_request_start: *const RequestStart,
-    http_request_intercept: *const RequestIntercept,
-    http_request_auth_required: *const RequestAuthRequired,
-    http_request_done: *const RequestDone,
-    http_response_data: *const ResponseData,
-    http_response_header_done: *const ResponseHeaderDone,
-    notification_created: *Notification,
-};
-const EventType = std.meta.FieldEnum(Events);
-
-pub const PageRemove = struct {};
-
-pub const PageNavigate = struct {
-    timestamp: u64,
-    url: []const u8,
-    opts: Page.NavigateOpts,
-};
-
-pub const PageNavigated = struct {
-    timestamp: u64,
-    url: []const u8,
-};
-
-pub const PageNetworkIdle = struct {
-    timestamp: u64,
-};
-
-pub const PageNetworkAlmostIdle = struct {
-    timestamp: u64,
-};
-
-pub const RequestStart = struct {
-    transfer: *Transfer,
-};
-
-pub const RequestIntercept = struct {
-    transfer: *Transfer,
-    wait_for_interception: *bool,
-};
-
-pub const RequestAuthRequired = struct {
-    transfer: *Transfer,
-    wait_for_interception: *bool,
-};
-
-pub const ResponseData = struct {
-    data: []const u8,
-    transfer: *Transfer,
-};
-
-pub const ResponseHeaderDone = struct {
-    transfer: *Transfer,
-};
-
-pub const RequestDone = struct {
-    transfer: *Transfer,
-};
-
-pub const RequestFail = struct {
-    transfer: *Transfer,
-    err: anyerror,
-};
-
-pub fn init(allocator: Allocator, parent: ?*Notification) !*Notification {
-
-    // This is put on the heap because we want to raise a .notification_created
-    // event, so that, something like Telemetry, can receive the
-    // .page_navigate event on all notification instances. That can only work
-    // if we dispatch .notification_created with a *Notification.
-    const notification = try allocator.create(Notification);
-    errdefer allocator.destroy(notification);
-
-    notification.* = .{
-        .listeners = .{},
-        .event_listeners = .{},
-        .allocator = allocator,
-        .mem_pool = std.heap.MemoryPool(Listener).init(allocator),
-    };
-
-    if (parent) |pn| {
-        pn.dispatch(.notification_created, notification);
-    }
-
-    return notification;
-}
-
-pub fn deinit(self: *Notification) void {
-    const allocator = self.allocator;
-
-    var it = self.listeners.valueIterator();
-    while (it.next()) |listener| {
-        listener.deinit(allocator);
-    }
-    self.listeners.deinit(allocator);
-    self.mem_pool.deinit();
-    allocator.destroy(self);
-}
-
-pub fn register(self: *Notification, comptime event: EventType, receiver: anytype, func: EventFunc(event)) !void {
-    var list = &@field(self.event_listeners, @tagName(event));
-
-    var listener = try self.mem_pool.create();
-    errdefer self.mem_pool.destroy(listener);
-
-    listener.* = .{
-        .node = .{},
-        .list = list,
-        .receiver = receiver,
-        .event = event,
-        .func = @ptrCast(func),
-        .struct_name = @typeName(@typeInfo(@TypeOf(receiver)).pointer.child),
-    };
-
-    const allocator = self.allocator;
-    const gop = try self.listeners.getOrPut(allocator, @intFromPtr(receiver));
-    if (gop.found_existing == false) {
-        gop.value_ptr.* = .{};
-    }
-    try gop.value_ptr.append(allocator, listener);
-
-    // we don't add this until we've successfully added the entry to
-    // self.listeners
-    list.append(&listener.node);
-}
-
-pub fn unregister(self: *Notification, comptime event: EventType, receiver: anytype) void {
-    var listeners = self.listeners.getPtr(@intFromPtr(receiver)) orelse return;
-
-    var i: usize = 0;
-    while (i < listeners.items.len) {
-        const listener = listeners.items[i];
-        if (listener.event != event) {
-            i += 1;
-            continue;
-        }
-        listener.list.remove(&listener.node);
-        self.mem_pool.destroy(listener);
-        _ = listeners.swapRemove(i);
-    }
-
-    if (listeners.items.len == 0) {
-        listeners.deinit(self.allocator);
-        const removed = self.listeners.remove(@intFromPtr(receiver));
-        std.debug.assert(removed == true);
-    }
-}
-
-pub fn unregisterAll(self: *Notification, receiver: *anyopaque) void {
-    var kv = self.listeners.fetchRemove(@intFromPtr(receiver)) orelse return;
-    for (kv.value.items) |listener| {
-        listener.list.remove(&listener.node);
-        self.mem_pool.destroy(listener);
-    }
-    kv.value.deinit(self.allocator);
-}
-
-pub fn dispatch(self: *Notification, comptime event: EventType, data: ArgType(event)) void {
-    const list = &@field(self.event_listeners, @tagName(event));
-
-    var node = list.first;
-    while (node) |n| {
-        const listener: *Listener = @fieldParentPtr("node", n);
-        const func: EventFunc(event) = @ptrCast(@alignCast(listener.func));
-        func(listener.receiver, data) catch |err| {
-            log.err(.app, "dispatch error", .{
-                .err = err,
-                .event = event,
-                .source = "notification",
-                .listener = listener.struct_name,
-            });
-        };
-        node = n.next;
-    }
-}
-
-// Given an event type enum, returns the type of arg the event emits
-fn ArgType(comptime event: Notification.EventType) type {
-    inline for (std.meta.fields(Notification.Events)) |f| {
-        if (std.mem.eql(u8, f.name, @tagName(event))) {
-            return f.type;
-        }
-    }
-    unreachable;
-}
-
-// Given an event type enum, returns the listening function type
-fn EventFunc(comptime event: Notification.EventType) type {
-    return *const fn (*anyopaque, ArgType(event)) anyerror!void;
-}
-
-// A listener. This is 1 receiver, with its function, and the linked list
-// node that goes in the appropriate EventListeners list.
-const Listener = struct {
-    // the receiver of the event, i.e. the self parameter to `func`
-    receiver: *anyopaque,
-
-    // the function to call
-    func: *const anyopaque,
-
-    // For logging slightly better error
-    struct_name: []const u8,
-
-    event: Notification.EventType,
-
-    // intrusive linked list node
-    node: List.Node,
-
-    // The event list this listener belongs to.
-    // We need this in order to be able to remove the node from the list
-    list: *List,
-};
-
-const testing = std.testing;
-test "Notification" {
-    var notifier = try Notification.init(testing.allocator, null);
-    defer notifier.deinit();
-
-    // noop
-    notifier.dispatch(.page_navigate, &.{
-        .timestamp = 4,
-        .url = undefined,
-        .opts = .{},
-    });
-
-    var tc = TestClient{};
-
-    try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
-    notifier.dispatch(.page_navigate, &.{
-        .timestamp = 4,
-        .url = undefined,
-        .opts = .{},
-    });
-    try testing.expectEqual(4, tc.page_navigate);
-
-    notifier.unregisterAll(&tc);
-    notifier.dispatch(.page_navigate, &.{
-        .timestamp = 10,
-        .url = undefined,
-        .opts = .{},
-    });
-    try testing.expectEqual(4, tc.page_navigate);
-
-    try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
-    try notifier.register(.page_navigated, &tc, TestClient.pageNavigated);
-    notifier.dispatch(.page_navigate, &.{
-        .timestamp = 10,
-        .url = undefined,
-        .opts = .{},
-    });
-    notifier.dispatch(.page_navigated, &.{ .timestamp = 6, .url = undefined });
-    try testing.expectEqual(14, tc.page_navigate);
-    try testing.expectEqual(6, tc.page_navigated);
-
-    notifier.unregisterAll(&tc);
-    notifier.dispatch(.page_navigate, &.{
-        .timestamp = 100,
-        .url = undefined,
-        .opts = .{},
-    });
-    notifier.dispatch(.page_navigated, &.{ .timestamp = 100, .url = undefined });
-    try testing.expectEqual(14, tc.page_navigate);
-    try testing.expectEqual(6, tc.page_navigated);
-
-    {
-        // unregister
-        try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
-        try notifier.register(.page_navigated, &tc, TestClient.pageNavigated);
-        notifier.dispatch(.page_navigate, &.{ .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .timestamp = 1000, .url = undefined });
-        try testing.expectEqual(114, tc.page_navigate);
-        try testing.expectEqual(1006, tc.page_navigated);
-
-        notifier.unregister(.page_navigate, &tc);
-        notifier.dispatch(.page_navigate, &.{ .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .timestamp = 1000, .url = undefined });
-        try testing.expectEqual(114, tc.page_navigate);
-        try testing.expectEqual(2006, tc.page_navigated);
-
-        notifier.unregister(.page_navigated, &tc);
-        notifier.dispatch(.page_navigate, &.{ .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .timestamp = 1000, .url = undefined });
-        try testing.expectEqual(114, tc.page_navigate);
-        try testing.expectEqual(2006, tc.page_navigated);
-
-        // already unregistered, try anyways
-        notifier.unregister(.page_navigated, &tc);
-        notifier.dispatch(.page_navigate, &.{ .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .timestamp = 1000, .url = undefined });
-        try testing.expectEqual(114, tc.page_navigate);
-        try testing.expectEqual(2006, tc.page_navigated);
-    }
-}
-
-const TestClient = struct {
-    page_navigate: u64 = 0,
-    page_navigated: u64 = 0,
-
-    fn pageNavigate(ptr: *anyopaque, data: *const Notification.PageNavigate) !void {
-        const self: *TestClient = @ptrCast(@alignCast(ptr));
-        self.page_navigate += data.timestamp;
-    }
-
-    fn pageNavigated(ptr: *anyopaque, data: *const Notification.PageNavigated) !void {
-        const self: *TestClient = @ptrCast(@alignCast(ptr));
-        self.page_navigated += data.timestamp;
-    }
-};
--- a/src/Scheduler.zig
+++ b/src/Scheduler.zig
@@ -1,88 +0,0 @@
-const std = @import("std");
-const log = @import("log.zig");
-
-const timestamp = @import("datetime.zig").milliTimestamp;
-
-const Queue = std.PriorityQueue(Task, void, struct {
-    fn compare(_: void, a: Task, b: Task) std.math.Order {
-        return std.math.order(a.run_at, b.run_at);
-    }
-}.compare);
-
-const Scheduler = @This();
-
-low_priority: Queue,
-high_priority: Queue,
-
-pub fn init(allocator: std.mem.Allocator) Scheduler {
-    return .{
-        .low_priority = Queue.init(allocator, {}),
-        .high_priority = Queue.init(allocator, {}),
-    };
-}
-
-pub fn reset(self: *Scheduler) void {
-    self.low_priority.cap = 0;
-    self.low_priority.items.len = 0;
-
-    self.high_priority.cap = 0;
-    self.high_priority.items.len = 0;
-}
-
-const AddOpts = struct {
-    name: []const u8 = "",
-    low_priority: bool = false,
-};
-pub fn add(self: *Scheduler, ctx: *anyopaque, cb: Callback, run_in_ms: u32, opts: AddOpts) !void {
-    log.debug(.scheduler, "scheduler.add", .{ .name = opts.name, .run_in_ms = run_in_ms, .low_priority = opts.low_priority });
-    var queue = if (opts.low_priority) &self.low_priority else &self.high_priority;
-    return queue.add(.{
-        .ctx = ctx,
-        .callback = cb,
-        .name = opts.name,
-        .run_at = timestamp(.monotonic) + run_in_ms,
-    });
-}
-
-pub fn run(self: *Scheduler) !?u64 {
-    _ = try self.runQueue(&self.low_priority);
-    return self.runQueue(&self.high_priority);
-}
-
-fn runQueue(self: *Scheduler, queue: *Queue) !?u64 {
-    if (queue.count() == 0) {
-        return null;
-    }
-
-    const now = timestamp(.monotonic);
-
-    while (queue.peek()) |*task_| {
-        if (task_.run_at > now) {
-            return @intCast(task_.run_at - now);
-        }
-        var task = queue.remove();
-        log.debug(.scheduler, "scheduler.runTask", .{ .name = task.name });
-
-        const repeat_in_ms = task.callback(task.ctx) catch |err| {
-            log.warn(.scheduler, "task.callback", .{ .name = task.name, .err = err });
-            continue;
-        };
-
-        if (repeat_in_ms) |ms| {
-            // Task cannot be repeated immediately, and they should know that
-            std.debug.assert(ms != 0);
-            task.run_at = now + ms;
-            try self.low_priority.add(task);
-        }
-    }
-    return null;
-}
-
-const Task = struct {
-    run_at: u64,
-    ctx: *anyopaque,
-    name: []const u8,
-    callback: Callback,
-};
-
-const Callback = *const fn (ctx: *anyopaque) anyerror!?u32;
--- a/src/TestHTTPServer.zig
+++ b/src/TestHTTPServer.zig
@@ -1,119 +0,0 @@
-const std = @import("std");
-
-const TestHTTPServer = @This();
-
-shutdown: bool,
-listener: ?std.net.Server,
-handler: Handler,
-
-const Handler = *const fn (req: *std.http.Server.Request) anyerror!void;
-
-pub fn init(handler: Handler) TestHTTPServer {
-    return .{
-        .shutdown = true,
-        .listener = null,
-        .handler = handler,
-    };
-}
-
-pub fn deinit(self: *TestHTTPServer) void {
-    self.shutdown = true;
-    if (self.listener) |*listener| {
-        listener.deinit();
-    }
-}
-
-pub fn run(self: *TestHTTPServer, wg: *std.Thread.WaitGroup) !void {
-    const address = try std.net.Address.parseIp("127.0.0.1", 9582);
-
-    self.listener = try address.listen(.{ .reuse_address = true });
-    var listener = &self.listener.?;
-
-    wg.finish();
-
-    while (true) {
-        const conn = listener.accept() catch |err| {
-            if (self.shutdown) {
-                return;
-            }
-            return err;
-        };
-        const thrd = try std.Thread.spawn(.{}, handleConnection, .{ self, conn });
-        thrd.detach();
-    }
-}
-
-fn handleConnection(self: *TestHTTPServer, conn: std.net.Server.Connection) !void {
-    defer conn.stream.close();
-
-    var req_buf: [2048]u8 = undefined;
-    var conn_reader = conn.stream.reader(&req_buf);
-    var conn_writer = conn.stream.writer(&req_buf);
-
-    var http_server = std.http.Server.init(conn_reader.interface(), &conn_writer.interface);
-
-    while (true) {
-        var req = http_server.receiveHead() catch |err| switch (err) {
-            error.ReadFailed => continue,
-            error.HttpConnectionClosing => continue,
-            else => {
-                std.debug.print("Test HTTP Server error: {}\n", .{err});
-                return err;
-            },
-        };
-
-        self.handler(&req) catch |err| {
-            std.debug.print("test http error '{s}': {}\n", .{ req.head.target, err });
-            try req.respond("server error", .{ .status = .internal_server_error });
-            return;
-        };
-    }
-}
-
-pub fn sendFile(req: *std.http.Server.Request, file_path: []const u8) !void {
-    var file = std.fs.cwd().openFile(file_path, .{}) catch |err| switch (err) {
-        error.FileNotFound => return req.respond("server error", .{ .status = .not_found }),
-        else => return err,
-    };
-    defer file.close();
-
-    const stat = try file.stat();
-    var send_buffer: [4096]u8 = undefined;
-
-    var res = try req.respondStreaming(&send_buffer, .{
-        .content_length = stat.size,
-        .respond_options = .{
-            .extra_headers = &.{
-                .{ .name = "content-type", .value = getContentType(file_path) },
-            },
-        },
-    });
-
-    var read_buffer: [4096]u8 = undefined;
-    var reader = file.reader(&read_buffer);
-    _ = try res.writer.sendFileAll(&reader, .unlimited);
-    try res.writer.flush();
-    try res.end();
-}
-
-fn getContentType(file_path: []const u8) []const u8 {
-    if (std.mem.endsWith(u8, file_path, ".js")) {
-        return "application/json";
-    }
-
-    if (std.mem.endsWith(u8, file_path, ".html")) {
-        return "text/html";
-    }
-
-    if (std.mem.endsWith(u8, file_path, ".htm")) {
-        return "text/html";
-    }
-
-    if (std.mem.endsWith(u8, file_path, ".xml")) {
-        // some wpt tests do this
-        return "text/xml";
-    }
-
-    std.debug.print("TestHTTPServer asked to serve an unknown file type: {s}\n", .{file_path});
-    return "text/html";
-}
--- a/src/app.zig
+++ b/src/app.zig
@@ -0,0 +1,109 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const log = @import("log.zig");
+const Loop = @import("runtime/loop.zig").Loop;
+const http = @import("http/client.zig");
+const Platform = @import("runtime/js.zig").Platform;
+
+const Telemetry = @import("telemetry/telemetry.zig").Telemetry;
+const Notification = @import("notification.zig").Notification;
+
+// Container for global state / objects that various parts of the system
+// might need.
+pub const App = struct {
+    loop: *Loop,
+    config: Config,
+    platform: ?*const Platform,
+    allocator: Allocator,
+    telemetry: Telemetry,
+    http_client: http.Client,
+    app_dir_path: ?[]const u8,
+    notification: *Notification,
+
+    pub const RunMode = enum {
+        help,
+        fetch,
+        serve,
+        version,
+    };
+
+    pub const Config = struct {
+        run_mode: RunMode,
+        platform: ?*const Platform = null,
+        tls_verify_host: bool = true,
+        http_proxy: ?std.Uri = null,
+        proxy_type: ?http.ProxyType = null,
+        proxy_auth: ?http.ProxyAuth = null,
+    };
+
+    pub fn init(allocator: Allocator, config: Config) !*App {
+        const app = try allocator.create(App);
+        errdefer allocator.destroy(app);
+
+        const loop = try allocator.create(Loop);
+        errdefer allocator.destroy(loop);
+
+        loop.* = try Loop.init(allocator);
+        errdefer loop.deinit();
+
+        const notification = try Notification.init(allocator, null);
+        errdefer notification.deinit();
+
+        const app_dir_path = getAndMakeAppDir(allocator);
+
+        app.* = .{
+            .loop = loop,
+            .allocator = allocator,
+            .telemetry = undefined,
+            .platform = config.platform,
+            .app_dir_path = app_dir_path,
+            .notification = notification,
+            .http_client = try http.Client.init(allocator, loop, .{
+                .max_concurrent = 3,
+                .http_proxy = config.http_proxy,
+                .proxy_type = config.proxy_type,
+                .proxy_auth = config.proxy_auth,
+                .tls_verify_host = config.tls_verify_host,
+            }),
+            .config = config,
+        };
+        app.telemetry = Telemetry.init(app, config.run_mode);
+        try app.telemetry.register(app.notification);
+
+        return app;
+    }
+
+    pub fn deinit(self: *App) void {
+        const allocator = self.allocator;
+        if (self.app_dir_path) |app_dir_path| {
+            allocator.free(app_dir_path);
+        }
+        self.telemetry.deinit();
+        self.loop.deinit();
+        allocator.destroy(self.loop);
+        self.http_client.deinit();
+        self.notification.deinit();
+        allocator.destroy(self);
+    }
+};
+
+fn getAndMakeAppDir(allocator: Allocator) ?[]const u8 {
+    if (@import("builtin").is_test) {
+        return allocator.dupe(u8, "/tmp") catch unreachable;
+    }
+    const app_dir_path = std.fs.getAppDataDir(allocator, "lightpanda") catch |err| {
+        log.warn(.app, "get data dir", .{ .err = err });
+        return null;
+    };
+
+    std.fs.cwd().makePath(app_dir_path) catch |err| switch (err) {
+        error.PathAlreadyExists => return app_dir_path,
+        else => {
+            allocator.free(app_dir_path);
+            log.warn(.app, "create data dir", .{ .err = err, .path = app_dir_path });
+            return null;
+        },
+    };
+    return app_dir_path;
+}
--- a/src/browser/Browser.zig
+++ b/src/browser/Browser.zig
@@ -1,115 +0,0 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const Allocator = std.mem.Allocator;
-const ArenaAllocator = std.heap.ArenaAllocator;
-
-const js = @import("js/js.zig");
-const log = @import("../log.zig");
-const App = @import("../App.zig");
-const HttpClient = @import("../http/Client.zig");
-const Notification = @import("../Notification.zig");
-
-const Session = @import("Session.zig");
-
-// Browser is an instance of the browser.
-// You can create multiple browser instances.
-// A browser contains only one session.
-const Browser = @This();
-
-env: *js.Env,
-app: *App,
-session: ?Session,
-allocator: Allocator,
-http_client: *HttpClient,
-call_arena: ArenaAllocator,
-page_arena: ArenaAllocator,
-session_arena: ArenaAllocator,
-transfer_arena: ArenaAllocator,
-notification: *Notification,
-
-pub fn init(app: *App) !Browser {
-    const allocator = app.allocator;
-
-    const env = try js.Env.init(allocator, &app.platform, .{});
-    errdefer env.deinit();
-
-    const notification = try Notification.init(allocator, app.notification);
-    app.http.client.notification = notification;
-    app.http.client.next_request_id = 0; // Should we track ids in CDP only?
-    errdefer notification.deinit();
-
-    return .{
-        .app = app,
-        .env = env,
-        .session = null,
-        .allocator = allocator,
-        .notification = notification,
-        .http_client = app.http.client,
-        .call_arena = ArenaAllocator.init(allocator),
-        .page_arena = ArenaAllocator.init(allocator),
-        .session_arena = ArenaAllocator.init(allocator),
-        .transfer_arena = ArenaAllocator.init(allocator),
-    };
-}
-
-pub fn deinit(self: *Browser) void {
-    self.closeSession();
-    self.env.deinit();
-    self.call_arena.deinit();
-    self.page_arena.deinit();
-    self.session_arena.deinit();
-    self.transfer_arena.deinit();
-    self.http_client.notification = null;
-    self.notification.deinit();
-}
-
-pub fn newSession(self: *Browser) !*Session {
-    self.closeSession();
-    self.session = @as(Session, undefined);
-    const session = &self.session.?;
-    try Session.init(session, self);
-    return session;
-}
-
-pub fn closeSession(self: *Browser) void {
-    if (self.session) |*session| {
-        session.deinit();
-        self.session = null;
-        _ = self.session_arena.reset(.{ .retain_with_limit = 1 * 1024 * 1024 });
-        self.env.lowMemoryNotification();
-    }
-}
-
-pub fn runMicrotasks(self: *const Browser) void {
-    self.env.runMicrotasks();
-}
-
-pub fn runMessageLoop(self: *const Browser) void {
-    while (self.env.pumpMessageLoop()) {
-        log.debug(.browser, "pumpMessageLoop", .{});
-    }
-    self.env.runIdleTasks();
-}
-
-const testing = @import("../testing.zig");
-test "Browser" {
-    try testing.htmlRunner("browser.html", .{});
-}
--- a/src/browser/EventManager.zig
+++ b/src/browser/EventManager.zig
@@ -1,294 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-
-const log = @import("../log.zig");
-const String = @import("../string.zig").String;
-
-const js = @import("js/js.zig");
-const Page = @import("Page.zig");
-
-const Node = @import("webapi/Node.zig");
-const Event = @import("webapi/Event.zig");
-const EventTarget = @import("webapi/EventTarget.zig");
-
-const Allocator = std.mem.Allocator;
-
-const IS_DEBUG = builtin.mode == .Debug;
-
-pub const EventManager = @This();
-
-page: *Page,
-arena: Allocator,
-listener_pool: std.heap.MemoryPool(Listener),
-lookup: std.AutoHashMapUnmanaged(usize, std.DoublyLinkedList),
-
-pub fn init(page: *Page) EventManager {
-    return .{
-        .page = page,
-        .lookup = .{},
-        .arena = page.arena,
-        .listener_pool = std.heap.MemoryPool(Listener).init(page.arena),
-    };
-}
-
-pub const RegisterOptions = struct {
-    once: bool = false,
-    capture: bool = false,
-    passive: bool = false,
-    signal: ?*@import("webapi/AbortSignal.zig") = null,
-};
-pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, function: js.Function, opts: RegisterOptions) !void {
-    if (comptime IS_DEBUG) {
-        log.debug(.event, "eventManager.register", .{ .type = typ, .capture = opts.capture, .once = opts.once });
-    }
-
-    // If a signal is provided and already aborted, don't register the listener
-    if (opts.signal) |signal| {
-        if (signal.getAborted()) {
-            return;
-        }
-    }
-
-    const gop = try self.lookup.getOrPut(self.arena, @intFromPtr(target));
-    if (gop.found_existing) {
-        // check for duplicate functions already registered
-        var node = gop.value_ptr.first;
-        while (node) |n| {
-            const listener: *Listener = @alignCast(@fieldParentPtr("node", n));
-            if (listener.function.eql(function) and listener.capture == opts.capture) {
-                return;
-            }
-            node = n.next;
-        }
-    } else {
-        gop.value_ptr.* = .{};
-    }
-
-    const listener = try self.listener_pool.create();
-    listener.* = .{
-        .node = .{},
-        .once = opts.once,
-        .capture = opts.capture,
-        .passive = opts.passive,
-        .function = .{ .value = function },
-        .signal = opts.signal,
-        .typ = try String.init(self.arena, typ, .{}),
-    };
-    // append the listener to the list of listeners for this target
-    gop.value_ptr.append(&listener.node);
-}
-
-pub fn remove(self: *EventManager, target: *EventTarget, typ: []const u8, function: js.Function, use_capture: bool) void {
-    const list = self.lookup.getPtr(@intFromPtr(target)) orelse return;
-    if (findListener(list, typ, function, use_capture)) |listener| {
-        self.removeListener(list, listener);
-    }
-}
-
-pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) !void {
-    if (comptime IS_DEBUG) {
-        log.debug(.event, "eventManager.dispatch", .{ .type = event._type_string.str(), .bubbles = event._bubbles });
-    }
-    event._target = target;
-    switch (target._type) {
-        .node => |node| try self.dispatchNode(node, event),
-        .xhr, .window, .abort_signal => {
-            const list = self.lookup.getPtr(@intFromPtr(target)) orelse return;
-            try self.dispatchAll(list, target, event);
-        },
-    }
-}
-
-// There are a lot of events that can be attached via addEventListener or as
-// a property, like the XHR events, or window.onload. You might think that the
-// property is just a shortcut for calling addEventListener, but they are distinct.
-// An event set via property cannot be removed by removeEventListener. If you
-// set both the property and add a listener, they both execute.
-const DispatchWithFunctionOptions = struct {
-    context: []const u8,
-    inject_target: bool = true,
-};
-pub fn dispatchWithFunction(self: *EventManager, target: *EventTarget, event: *Event, function_: ?js.Function, comptime opts: DispatchWithFunctionOptions) !void {
-    if (comptime IS_DEBUG) {
-        log.debug(.event, "dispatchWithFunction", .{ .type = event._type_string.str(), .context = opts.context, .has_function = function_ != null });
-    }
-
-    if (comptime opts.inject_target) {
-        event._target = target;
-    }
-
-    if (function_) |func| {
-        event._current_target = target;
-        func.call(void, .{event}) catch |err| {
-            // a non-JS error
-            log.warn(.event, opts.context, .{ .err = err });
-        };
-    }
-
-    const list = self.lookup.getPtr(@intFromPtr(target)) orelse return;
-    try self.dispatchAll(list, target, event);
-}
-
-fn dispatchNode(self: *EventManager, target: *Node, event: *Event) !void {
-    var path_len: usize = 0;
-    var path_buffer: [128]*EventTarget = undefined;
-
-    var node: ?*Node = target;
-    while (node) |n| : (node = n._parent) {
-        if (path_len >= path_buffer.len) break;
-        path_buffer[path_len] = n.asEventTarget();
-        path_len += 1;
-    }
-
-    // Even though the window isn't part of the DOM, events always propagate
-    // through it in the capture phase
-    if (path_len < path_buffer.len) {
-        path_buffer[path_len] = self.page.window.asEventTarget();
-        path_len += 1;
-    }
-
-    const path = path_buffer[0..path_len];
-
-    // Phase 1: Capturing phase (root → target, excluding target)
-    // This happens for all events, regardless of bubbling
-    event._event_phase = .capturing_phase;
-    var i: usize = path_len;
-    while (i > 1) {
-        i -= 1;
-        const current_target = path[i];
-        if (self.lookup.getPtr(@intFromPtr(current_target))) |list| {
-            try self.dispatchPhase(list, current_target, event, true);
-            if (event._stop_propagation) {
-                event._event_phase = .none;
-                return;
-            }
-        }
-    }
-
-    // Phase 2: At target
-    event._event_phase = .at_target;
-    const target_et = target.asEventTarget();
-    if (self.lookup.getPtr(@intFromPtr(target_et))) |list| {
-        try self.dispatchPhase(list, target_et, event, null);
-        if (event._stop_propagation) {
-            event._event_phase = .none;
-            return;
-        }
-    }
-
-    // Phase 3: Bubbling phase (target → root, excluding target)
-    // This only happens if the event bubbles
-    if (event._bubbles) {
-        event._event_phase = .bubbling_phase;
-        for (path[1..]) |current_target| {
-            if (self.lookup.getPtr(@intFromPtr(current_target))) |list| {
-                try self.dispatchPhase(list, current_target, event, false);
-                if (event._stop_propagation) {
-                    break;
-                }
-            }
-        }
-    }
-
-    event._event_phase = .none;
-}
-
-fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event, comptime capture_only: ?bool) !void {
-    const page = self.page;
-    const typ = event._type_string;
-
-    var node = list.first;
-    while (node) |n| {
-        // do this now, in case we need to remove n (once: true or aborted signal)
-        node = n.next;
-
-        const listener: *Listener = @alignCast(@fieldParentPtr("node", n));
-        if (!listener.typ.eql(typ)) {
-            continue;
-        }
-
-        // Can be null when dispatching to the target itself
-        if (comptime capture_only) |capture| {
-            if (listener.capture != capture) {
-                continue;
-            }
-        }
-
-        // If the listener has an aborted signal, remove it and skip
-        if (listener.signal) |signal| {
-            if (signal.getAborted()) {
-                self.removeListener(list, listener);
-                continue;
-            }
-        }
-
-        event._current_target = current_target;
-
-        switch (listener.function) {
-            .value => |value| try value.call(void, .{event}),
-            .string => |string| {
-                const str = try page.call_arena.dupeZ(u8, string.str());
-                try self.page.js.eval(str, null);
-            },
-        }
-
-        if (listener.once) {
-            self.removeListener(list, listener);
-        }
-
-        if (event._stop_immediate_propagation) {
-            return;
-        }
-    }
-}
-
-//  Non-Node dispatching (XHR, Window without propagation)
-fn dispatchAll(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event) !void {
-    return self.dispatchPhase(list, current_target, event, null);
-}
-
-fn removeListener(self: *EventManager, list: *std.DoublyLinkedList, listener: *Listener) void {
-    list.remove(&listener.node);
-    self.listener_pool.destroy(listener);
-}
-
-fn findListener(list: *const std.DoublyLinkedList, typ: []const u8, function: js.Function, capture: bool) ?*Listener {
-    var node = list.first;
-    while (node) |n| {
-        node = n.next;
-        const listener: *Listener = @alignCast(@fieldParentPtr("node", n));
-        if (!listener.function.eql(function)) {
-            continue;
-        }
-        if (listener.capture != capture) {
-            continue;
-        }
-        if (!listener.typ.eqlSlice(typ)) {
-            continue;
-        }
-        return listener;
-    }
-    return null;
-}
-
-const Listener = struct {
-    typ: String,
-    once: bool,
-    capture: bool,
-    passive: bool,
-    function: Function,
-    signal: ?*@import("webapi/AbortSignal.zig") = null,
-    node: std.DoublyLinkedList.Node,
-};
-
-const Function = union(enum) {
-    value: js.Function,
-    string: String,
-
-    fn eql(self: Function, func: js.Function) bool {
-        return switch (self) {
-            .string => false,
-            .value => |v| return v.id == func.id,
-        };
-    }
-};
--- a/src/browser/Factory.zig
+++ b/src/browser/Factory.zig
@@ -1,378 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-const reflect = @import("reflect.zig");
-const IS_DEBUG = builtin.mode == .Debug;
-
-const log = @import("../log.zig");
-const String = @import("../string.zig").String;
-
-const Page = @import("Page.zig");
-const Node = @import("webapi/Node.zig");
-const Event = @import("webapi/Event.zig");
-const Element = @import("webapi/Element.zig");
-const Document = @import("webapi/Document.zig");
-const EventTarget = @import("webapi/EventTarget.zig");
-const XMLHttpRequestEventTarget = @import("webapi/net/XMLHttpRequestEventTarget.zig");
-
-const MemoryPoolAligned = std.heap.MemoryPoolAligned;
-
-// 1. Generally, wrapping an ArenaAllocator within an ArenaAllocator doesn't make
-// much sense. But wrapping a MemoryPool within an Arena does. Specifically, by
-// doing so, we solve a major issue with Arena: freed memory can be re-used [for
-// more of the same size].
-// 2. Normally, you have a MemoryPool(T) where T is a `User` or something. Then
-// the MemoryPool can be used for creating users. But in reality, that memory
-// created by that pool could be re-used for anything with the same size (or less)
-// than a User (and a compatible alignment). So that's what we do - we have size
-// (and alignment) based pools.
-const Factory = @This();
-_page: *Page,
-_size_1_8: MemoryPoolAligned([1]u8, .@"8"),
-_size_8_8: MemoryPoolAligned([8]u8, .@"8"),
-_size_16_8: MemoryPoolAligned([16]u8, .@"8"),
-_size_24_8: MemoryPoolAligned([24]u8, .@"8"),
-_size_32_8: MemoryPoolAligned([32]u8, .@"8"),
-_size_32_16: MemoryPoolAligned([32]u8, .@"16"),
-_size_40_8: MemoryPoolAligned([40]u8, .@"8"),
-_size_48_16: MemoryPoolAligned([48]u8, .@"16"),
-_size_56_8: MemoryPoolAligned([56]u8, .@"8"),
-_size_64_16: MemoryPoolAligned([64]u8, .@"16"),
-_size_72_8: MemoryPoolAligned([72]u8, .@"8"),
-_size_80_16: MemoryPoolAligned([80]u8, .@"16"),
-_size_88_8: MemoryPoolAligned([88]u8, .@"8"),
-_size_96_16: MemoryPoolAligned([96]u8, .@"16"),
-_size_104_8: MemoryPoolAligned([104]u8, .@"8"),
-_size_112_8: MemoryPoolAligned([112]u8, .@"8"),
-_size_120_8: MemoryPoolAligned([120]u8, .@"8"),
-_size_128_8: MemoryPoolAligned([128]u8, .@"8"),
-_size_144_8: MemoryPoolAligned([144]u8, .@"8"),
-_size_456_8: MemoryPoolAligned([456]u8, .@"8"),
-_size_520_8: MemoryPoolAligned([520]u8, .@"8"),
-_size_648_8: MemoryPoolAligned([648]u8, .@"8"),
-
-pub fn init(page: *Page) Factory {
-    return .{
-        ._page = page,
-        ._size_1_8 = MemoryPoolAligned([1]u8, .@"8").init(page.arena),
-        ._size_8_8 = MemoryPoolAligned([8]u8, .@"8").init(page.arena),
-        ._size_16_8 = MemoryPoolAligned([16]u8, .@"8").init(page.arena),
-        ._size_24_8 = MemoryPoolAligned([24]u8, .@"8").init(page.arena),
-        ._size_32_8 = MemoryPoolAligned([32]u8, .@"8").init(page.arena),
-        ._size_32_16 = MemoryPoolAligned([32]u8, .@"16").init(page.arena),
-        ._size_40_8 = MemoryPoolAligned([40]u8, .@"8").init(page.arena),
-        ._size_48_16 = MemoryPoolAligned([48]u8, .@"16").init(page.arena),
-        ._size_56_8 = MemoryPoolAligned([56]u8, .@"8").init(page.arena),
-        ._size_64_16 = MemoryPoolAligned([64]u8, .@"16").init(page.arena),
-        ._size_72_8 = MemoryPoolAligned([72]u8, .@"8").init(page.arena),
-        ._size_80_16 = MemoryPoolAligned([80]u8, .@"16").init(page.arena),
-        ._size_88_8 = MemoryPoolAligned([88]u8, .@"8").init(page.arena),
-        ._size_96_16 = MemoryPoolAligned([96]u8, .@"16").init(page.arena),
-        ._size_104_8 = MemoryPoolAligned([104]u8, .@"8").init(page.arena),
-        ._size_112_8 = MemoryPoolAligned([112]u8, .@"8").init(page.arena),
-        ._size_120_8 = MemoryPoolAligned([120]u8, .@"8").init(page.arena),
-        ._size_128_8 = MemoryPoolAligned([128]u8, .@"8").init(page.arena),
-        ._size_144_8 = MemoryPoolAligned([144]u8, .@"8").init(page.arena),
-        ._size_456_8 = MemoryPoolAligned([456]u8, .@"8").init(page.arena),
-        ._size_520_8 = MemoryPoolAligned([520]u8, .@"8").init(page.arena),
-        ._size_648_8 = MemoryPoolAligned([648]u8, .@"8").init(page.arena),
-    };
-}
-
-// this is a root object
-pub fn eventTarget(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const child_ptr = try self.createT(@TypeOf(child));
-    child_ptr.* = child;
-
-    const et = try self.createT(EventTarget);
-    child_ptr._proto = et;
-    et.* = .{ ._type = unionInit(EventTarget.Type, child_ptr) };
-    return child_ptr;
-}
-
-pub fn node(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const child_ptr = try self.createT(@TypeOf(child));
-    child_ptr.* = child;
-    child_ptr._proto = try self.eventTarget(Node{
-        ._proto = undefined,
-        ._type = unionInit(Node.Type, child_ptr),
-    });
-    return child_ptr;
-}
-
-pub fn document(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const child_ptr = try self.createT(@TypeOf(child));
-    child_ptr.* = child;
-    child_ptr._proto = try self.node(Document{
-        ._proto = undefined,
-        ._type = unionInit(Document.Type, child_ptr),
-    });
-    return child_ptr;
-}
-
-pub fn element(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const child_ptr = try self.createT(@TypeOf(child));
-    child_ptr.* = child;
-    child_ptr._proto = try self.node(Element{
-        ._proto = undefined,
-        ._type = unionInit(Element.Type, child_ptr),
-    });
-    return child_ptr;
-}
-
-pub fn htmlElement(self: *Factory, child: anytype) !*@TypeOf(child) {
-    if (comptime fieldIsPointer(Element.Html.Type, @TypeOf(child))) {
-        const child_ptr = try self.createT(@TypeOf(child));
-        child_ptr.* = child;
-        child_ptr._proto = try self.element(Element.Html{
-            ._proto = undefined,
-            ._type = unionInit(Element.Html.Type, child_ptr),
-        });
-        return child_ptr;
-    }
-
-    // Our union type fields are usually pointers. But, at the leaf, they
-    // can be struct (if all they contain is the `_proto` field, then we might
-    // as well store it directly in the struct).
-
-    const html = try self.element(Element.Html{
-        ._proto = undefined,
-        ._type = unionInit(Element.Html.Type, child),
-    });
-    const field_name = comptime unionFieldName(Element.Html.Type, @TypeOf(child));
-    var child_ptr = &@field(html._type, field_name);
-    child_ptr._proto = html;
-    return child_ptr;
-}
-
-pub fn svgElement(self: *Factory, tag_name: []const u8, child: anytype) !*@TypeOf(child) {
-    if (@TypeOf(child) == Element.Svg) {
-        return self.element(child);
-    }
-
-    // will never allocate, can't fail
-    const tag_name_str = String.init(undefined, tag_name, .{}) catch unreachable;
-
-    if (comptime fieldIsPointer(Element.Svg.Type, @TypeOf(child))) {
-        const child_ptr = try self.createT(@TypeOf(child));
-        child_ptr.* = child;
-        child_ptr._proto = try self.element(Element.Svg{
-            ._proto = undefined,
-            ._tag_name = tag_name_str,
-            ._type = unionInit(Element.Svg.Type, child_ptr),
-        });
-        return child_ptr;
-    }
-
-    // Our union type fields are usually pointers. But, at the leaf, they
-    // can be struct (if all they contain is the `_proto` field, then we might
-    // as well store it directly in the struct).
-    const svg = try self.element(Element.Svg{
-        ._proto = undefined,
-        ._tag_name = tag_name_str,
-        ._type = unionInit(Element.Svg.Type, child),
-    });
-    const field_name = comptime unionFieldName(Element.Svg.Type, @TypeOf(child));
-    var child_ptr = &@field(svg._type, field_name);
-    child_ptr._proto = svg;
-    return child_ptr;
-}
-
-// this is a root object
-pub fn event(self: *Factory, typ: []const u8, child: anytype) !*@TypeOf(child) {
-    const child_ptr = try self.createT(@TypeOf(child));
-    child_ptr.* = child;
-
-    const e = try self.createT(Event);
-    child_ptr._proto = e;
-    e.* = .{
-        ._type = unionInit(Event.Type, child_ptr),
-        ._type_string = try String.init(self._page.arena, typ, .{}),
-    };
-    return child_ptr;
-}
-
-pub fn xhrEventTarget(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const et = try self.eventTarget(XMLHttpRequestEventTarget{
-        ._proto = undefined,
-        ._type = unionInit(XMLHttpRequestEventTarget.Type, child),
-    });
-    const field_name = comptime unionFieldName(XMLHttpRequestEventTarget.Type, @TypeOf(child));
-    var child_ptr = &@field(et._type, field_name);
-    child_ptr._proto = et;
-    return child_ptr;
-}
-
-pub fn create(self: *Factory, value: anytype) !*@TypeOf(value) {
-    const ptr = try self.createT(@TypeOf(value));
-    ptr.* = value;
-    return ptr;
-}
-
-pub fn createT(self: *Factory, comptime T: type) !*T {
-    const SO = @sizeOf(T);
-    if (comptime SO == 1) return @ptrCast(try self._size_1_8.create());
-    if (comptime SO == 8) return @ptrCast(try self._size_8_8.create());
-    if (comptime SO == 16) return @ptrCast(try self._size_16_8.create());
-    if (comptime SO == 24) return @ptrCast(try self._size_24_8.create());
-    if (comptime SO == 32) {
-        if (comptime @alignOf(T) == 8) return @ptrCast(try self._size_32_8.create());
-        if (comptime @alignOf(T) == 16) return @ptrCast(try self._size_32_16.create());
-    }
-    if (comptime SO == 40) return @ptrCast(try self._size_40_8.create());
-    if (comptime SO == 48) return @ptrCast(try self._size_48_16.create());
-    if (comptime SO == 56) return @ptrCast(try self._size_56_8.create());
-    if (comptime SO == 64) return @ptrCast(try self._size_64_16.create());
-    if (comptime SO == 72) return @ptrCast(try self._size_72_8.create());
-    if (comptime SO == 80) return @ptrCast(try self._size_80_16.create());
-    if (comptime SO == 88) return @ptrCast(try self._size_88_8.create());
-    if (comptime SO == 96) return @ptrCast(try self._size_96_16.create());
-    if (comptime SO == 104) return @ptrCast(try self._size_104_8.create());
-    if (comptime SO == 112) return @ptrCast(try self._size_112_8.create());
-    if (comptime SO == 120) return @ptrCast(try self._size_120_8.create());
-    if (comptime SO == 128) return @ptrCast(try self._size_128_8.create());
-    if (comptime SO == 144) return @ptrCast(try self._size_144_8.create());
-    if (comptime SO == 456) return @ptrCast(try self._size_456_8.create());
-    if (comptime SO == 520) return @ptrCast(try self._size_520_8.create());
-    if (comptime SO == 648) return @ptrCast(try self._size_648_8.create());
-    @compileError(std.fmt.comptimePrint("No pool configured for @sizeOf({d}), @alignOf({d}): ({s})", .{ SO, @alignOf(T), @typeName(T) }));
-}
-
-pub fn destroy(self: *Factory, value: anytype) void {
-    const S = reflect.Struct(@TypeOf(value));
-    if (comptime IS_DEBUG) {
-        // We should always destroy from the leaf down.
-        if (@hasField(S, "_type") and @typeInfo(@TypeOf(value._type)) == .@"union") {
-            // A Event{._type == .generic} (or any other similar types)
-            // _should_ be destoyed directly. The _type = .generic is a pseudo
-            // child
-            if (S != Event or value._type != .generic) {
-                log.fatal(.bug, "factory.destroy.event", .{ .type = @typeName(S) });
-                unreachable;
-            }
-        }
-    }
-
-    self.destroyChain(value, true);
-}
-
-fn destroyChain(self: *Factory, value: anytype, comptime first: bool) void {
-    const S = reflect.Struct(@TypeOf(value));
-
-    // This is initially called from a deinit. We don't want to call that
-    // same deinit. So when this is the first time destroyChain is called
-    // we don't call deinit (because we're in that deinit)
-    if (!comptime first) {
-        // But if it isn't the first time
-        if (@hasDecl(S, "deinit")) {
-            // And it has a deinit, we'll call it
-            switch (@typeInfo(@TypeOf(S.deinit)).@"fn".params.len) {
-                1 => value.deinit(),
-                2 => value.deinit(self._page),
-                else => @compileLog(@typeName(S) ++ " has an invalid deinit function"),
-            }
-        }
-    }
-
-    if (@hasField(S, "_proto")) {
-        self.destroyChain(value._proto, false);
-    } else if (@hasDecl(S, "JsApi")) {
-        // Doesn't have a _proto, but has a JsApi.
-        if (self._page.js.removeTaggedMapping(@intFromPtr(value))) |tagged| {
-            self._size_24_8.destroy(@ptrCast(tagged));
-        }
-    }
-
-    // Leaf types are allowed by be placed directly within their _proto
-    // (which makes sense when the @sizeOf(Leaf) == 8). These don't need to
-    // be (cannot be) freed. But we'll still free the chain.
-    if (comptime wasAllocated(S)) {
-        switch (@sizeOf(S)) {
-            1 => self._size_1_8.destroy(@ptrCast(@alignCast(value))),
-            8 => self._size_8_8.destroy(@ptrCast(@alignCast(value))),
-            16 => self._size_16_8.destroy(@ptrCast(value)),
-            24 => self._size_24_8.destroy(@ptrCast(value)),
-            32 => {
-                if (comptime @alignOf(S) == 8) {
-                    self._size_32_8.destroy(@ptrCast(value));
-                } else if (comptime @alignOf(S) == 16) {
-                    self._size_32_16.destroy(@ptrCast(value));
-                }
-            },
-            40 => self._size_40_8.destroy(@ptrCast(value)),
-            48 => self._size_48_16.destroy(@ptrCast(@alignCast(value))),
-            56 => self._size_56_8.destroy(@ptrCast(value)),
-            64 => self._size_64_16.destroy(@ptrCast(@alignCast(value))),
-            72 => self._size_72_8.destroy(@ptrCast(@alignCast(value))),
-            80 => self._size_80_16.destroy(@ptrCast(@alignCast(value))),
-            88 => self._size_88_8.destroy(@ptrCast(@alignCast(value))),
-            96 => self._size_96_16.destroy(@ptrCast(@alignCast(value))),
-            104 => self._size_104_8.destroy(@ptrCast(value)),
-            112 => self._size_112_8.destroy(@ptrCast(value)),
-            120 => self._size_120_8.destroy(@ptrCast(value)),
-            128 => self._size_128_8.destroy(@ptrCast(value)),
-            144 => self._size_144_8.destroy(@ptrCast(value)),
-            456 => self._size_456_8.destroy(@ptrCast(value)),
-            520 => self._size_520_8.destroy(@ptrCast(value)),
-            648 => self._size_648_8.destroy(@ptrCast(value)),
-            else => |SO| @compileError(std.fmt.comptimePrint("Don't know what I'm being asked to destroy @sizeOf({d}), @alignOf({d}): ({s})", .{ SO, @alignOf(S), @typeName(S) })),
-        }
-    }
-}
-
-fn wasAllocated(comptime S: type) bool {
-    // Whether it's heap allocate or not, we should have a pointer.
-    // (If it isn't heap allocated, it'll be a pointer from the proto's type
-    // e.g. &html._type.title)
-    if (!@hasField(S, "_proto")) {
-        // a root is always on the heap.
-        return true;
-    }
-
-    // the _proto type
-    const P = reflect.Struct(std.meta.fieldInfo(S, ._proto).type);
-
-    // the _proto._type type (the parent's _type union)
-    const U = std.meta.fieldInfo(P, ._type).type;
-    inline for (@typeInfo(U).@"union".fields) |field| {
-        if (field.type == S) {
-            // One of the types in the proto's _type union is this non-pointer
-            // structure, so it isn't heap allocted.
-            return false;
-        }
-    }
-    return true;
-}
-
-fn unionInit(comptime T: type, value: anytype) T {
-    const V = @TypeOf(value);
-    const field_name = comptime unionFieldName(T, V);
-    return @unionInit(T, field_name, value);
-}
-
-// There can be friction between comptime and runtime. Comptime has to
-// account for all possible types, even if some runtime flow makes certain
-// cases impossible. At runtime, we always call `unionFieldName` with the
-// correct struct or pointer type. But at comptime time, `unionFieldName`
-// is called with both variants (S and *S). So we use reflect.Struct().
-// This only works because we never have a union with a field S and another
-// field *S.
-fn unionFieldName(comptime T: type, comptime V: type) []const u8 {
-    inline for (@typeInfo(T).@"union".fields) |field| {
-        if (reflect.Struct(field.type) == reflect.Struct(V)) {
-            return field.name;
-        }
-    }
-    @compileError(@typeName(V) ++ " is not a valid type for " ++ @typeName(T) ++ ".type");
-}
-
-fn fieldIsPointer(comptime T: type, comptime V: type) bool {
-    inline for (@typeInfo(T).@"union".fields) |field| {
-        if (field.type == V) {
-            return false;
-        }
-        if (field.type == *V) {
-            return true;
-        }
-    }
-    @compileError(@typeName(V) ++ " is not a valid type for " ++ @typeName(T) ++ ".type");
-}
--- a/src/browser/Mime.zig
+++ b/src/browser/Mime.zig
@@ -1,518 +0,0 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const Mime = @This();
-content_type: ContentType,
-params: []const u8 = "",
-// IANA defines max. charset value length as 40.
-// We keep 41 for null-termination since HTML parser expects in this format.
-charset: [41]u8 = default_charset,
-
-/// String "UTF-8" continued by null characters.
-pub const default_charset = .{ 'U', 'T', 'F', '-', '8' } ++ .{0} ** 36;
-
-/// Mime with unknown Content-Type, empty params and empty charset.
-pub const unknown = Mime{ .content_type = .{ .unknown = {} } };
-
-pub const ContentTypeEnum = enum {
-    text_xml,
-    text_html,
-    text_javascript,
-    text_plain,
-    text_css,
-    application_json,
-    unknown,
-    other,
-};
-
-pub const ContentType = union(ContentTypeEnum) {
-    text_xml: void,
-    text_html: void,
-    text_javascript: void,
-    text_plain: void,
-    text_css: void,
-    application_json: void,
-    unknown: void,
-    other: struct { type: []const u8, sub_type: []const u8 },
-};
-
-/// Returns the null-terminated charset value.
-pub fn charsetString(mime: *const Mime) [:0]const u8 {
-    return @ptrCast(&mime.charset);
-}
-
-/// Removes quotes of value if quotes are given.
-///
-/// Currently we don't validate the charset.
-/// See section 2.3 Naming Requirements:
-/// https://datatracker.ietf.org/doc/rfc2978/
-fn parseCharset(value: []const u8) error{ CharsetTooBig, Invalid }![]const u8 {
-    // Cannot be larger than 40.
-    // https://datatracker.ietf.org/doc/rfc2978/
-    if (value.len > 40) return error.CharsetTooBig;
-
-    // If the first char is a quote, look for a pair.
-    if (value[0] == '"') {
-        if (value.len < 3 or value[value.len - 1] != '"') {
-            return error.Invalid;
-        }
-
-        return value[1 .. value.len - 1];
-    }
-
-    // No quotes.
-    return value;
-}
-
-pub fn parse(input: []u8) !Mime {
-    if (input.len > 255) {
-        return error.TooBig;
-    }
-
-    // Zig's trim API is broken. The return type is always `[]const u8`,
-    // even if the input type is `[]u8`. @constCast is safe here.
-    var normalized = @constCast(std.mem.trim(u8, input, &std.ascii.whitespace));
-    _ = std.ascii.lowerString(normalized, normalized);
-
-    const content_type, const type_len = try parseContentType(normalized);
-    if (type_len >= normalized.len) {
-        return .{ .content_type = content_type };
-    }
-
-    const params = trimLeft(normalized[type_len..]);
-
-    var charset: [41]u8 = undefined;
-
-    var it = std.mem.splitScalar(u8, params, ';');
-    while (it.next()) |attr| {
-        const i = std.mem.indexOfScalarPos(u8, attr, 0, '=') orelse return error.Invalid;
-        const name = trimLeft(attr[0..i]);
-
-        const value = trimRight(attr[i + 1 ..]);
-        if (value.len == 0) {
-            return error.Invalid;
-        }
-
-        const attribute_name = std.meta.stringToEnum(enum {
-            charset,
-        }, name) orelse continue;
-
-        switch (attribute_name) {
-            .charset => {
-                if (value.len == 0) {
-                    break;
-                }
-
-                const attribute_value = try parseCharset(value);
-                @memcpy(charset[0..attribute_value.len], attribute_value);
-                // Null-terminate right after attribute value.
-                charset[attribute_value.len] = 0;
-            },
-        }
-    }
-
-    return .{
-        .params = params,
-        .charset = charset,
-        .content_type = content_type,
-    };
-}
-
-pub fn sniff(body: []const u8) ?Mime {
-    // 0x0C is form feed
-    const content = std.mem.trimLeft(u8, body, &.{ ' ', '\t', '\n', '\r', 0x0C });
-    if (content.len == 0) {
-        return null;
-    }
-
-    if (content[0] != '<') {
-        if (std.mem.startsWith(u8, content, &.{ 0xEF, 0xBB, 0xBF })) {
-            // UTF-8 BOM
-            return .{ .content_type = .{ .text_plain = {} } };
-        }
-        if (std.mem.startsWith(u8, content, &.{ 0xFE, 0xFF })) {
-            // UTF-16 big-endian BOM
-            return .{ .content_type = .{ .text_plain = {} } };
-        }
-        if (std.mem.startsWith(u8, content, &.{ 0xFF, 0xFE })) {
-            // UTF-16 little-endian BOM
-            return .{ .content_type = .{ .text_plain = {} } };
-        }
-        return null;
-    }
-
-    // The longest prefix we have is "<!DOCTYPE HTML ", 15 bytes. If we're
-    // here, we already know content[0] == '<', so we can skip that. So 14
-    // bytes.
-
-    // +1 because we don't need the leading '<'
-    var buf: [14]u8 = undefined;
-
-    const stripped = content[1..];
-    const prefix_len = @min(stripped.len, buf.len);
-    const prefix = std.ascii.lowerString(&buf, stripped[0..prefix_len]);
-
-    // we already know it starts with a <
-    const known_prefixes = [_]struct { []const u8, ContentType }{
-        .{ "!doctype html", .{ .text_html = {} } },
-        .{ "html", .{ .text_html = {} } },
-        .{ "script", .{ .text_html = {} } },
-        .{ "iframe", .{ .text_html = {} } },
-        .{ "h1", .{ .text_html = {} } },
-        .{ "div", .{ .text_html = {} } },
-        .{ "font", .{ .text_html = {} } },
-        .{ "table", .{ .text_html = {} } },
-        .{ "a", .{ .text_html = {} } },
-        .{ "style", .{ .text_html = {} } },
-        .{ "title", .{ .text_html = {} } },
-        .{ "b", .{ .text_html = {} } },
-        .{ "body", .{ .text_html = {} } },
-        .{ "br", .{ .text_html = {} } },
-        .{ "p", .{ .text_html = {} } },
-        .{ "!--", .{ .text_html = {} } },
-        .{ "xml", .{ .text_xml = {} } },
-    };
-    inline for (known_prefixes) |kp| {
-        const known_prefix = kp.@"0";
-        if (std.mem.startsWith(u8, prefix, known_prefix) and prefix.len > known_prefix.len) {
-            const next = prefix[known_prefix.len];
-            // a "tag-terminating-byte"
-            if (next == ' ' or next == '>') {
-                return .{ .content_type = kp.@"1" };
-            }
-        }
-    }
-
-    return null;
-}
-
-pub fn isHTML(self: *const Mime) bool {
-    return self.content_type == .text_html;
-}
-
-// we expect value to be lowercase
-fn parseContentType(value: []const u8) !struct { ContentType, usize } {
-    const end = std.mem.indexOfScalarPos(u8, value, 0, ';') orelse value.len;
-    const type_name = trimRight(value[0..end]);
-    const attribute_start = end + 1;
-
-    if (std.meta.stringToEnum(enum {
-        @"text/xml",
-        @"text/html",
-        @"text/css",
-        @"text/plain",
-
-        @"text/javascript",
-        @"application/javascript",
-        @"application/x-javascript",
-
-        @"application/json",
-    }, type_name)) |known_type| {
-        const ct: ContentType = switch (known_type) {
-            .@"text/xml" => .{ .text_xml = {} },
-            .@"text/html" => .{ .text_html = {} },
-            .@"text/javascript", .@"application/javascript", .@"application/x-javascript" => .{ .text_javascript = {} },
-            .@"text/plain" => .{ .text_plain = {} },
-            .@"text/css" => .{ .text_css = {} },
-            .@"application/json" => .{ .application_json = {} },
-        };
-        return .{ ct, attribute_start };
-    }
-
-    const separator = std.mem.indexOfScalarPos(u8, type_name, 0, '/') orelse return error.Invalid;
-
-    const main_type = value[0..separator];
-    const sub_type = trimRight(value[separator + 1 .. end]);
-
-    if (main_type.len == 0 or validType(main_type) == false) {
-        return error.Invalid;
-    }
-    if (sub_type.len == 0 or validType(sub_type) == false) {
-        return error.Invalid;
-    }
-
-    return .{ .{ .other = .{
-        .type = main_type,
-        .sub_type = sub_type,
-    } }, attribute_start };
-}
-
-const T_SPECIAL = blk: {
-    var v = [_]bool{false} ** 256;
-    for ("()<>@,;:\\\"/[]?=") |b| {
-        v[b] = true;
-    }
-    break :blk v;
-};
-
-const VALID_CODEPOINTS = blk: {
-    var v: [256]bool = undefined;
-    for (0..256) |i| {
-        v[i] = std.ascii.isAlphanumeric(i);
-    }
-    for ("!#$%&\\*+-.^'_`|~") |b| {
-        v[b] = true;
-    }
-    break :blk v;
-};
-
-fn validType(value: []const u8) bool {
-    for (value) |b| {
-        if (VALID_CODEPOINTS[b] == false) {
-            return false;
-        }
-    }
-    return true;
-}
-
-fn trimLeft(s: []const u8) []const u8 {
-    return std.mem.trimLeft(u8, s, &std.ascii.whitespace);
-}
-
-fn trimRight(s: []const u8) []const u8 {
-    return std.mem.trimRight(u8, s, &std.ascii.whitespace);
-}
-
-const testing = @import("../testing.zig");
-test "Mime: invalid" {
-    defer testing.reset();
-
-    const invalids = [_][]const u8{
-        "",
-        "text",
-        "text /html",
-        "text/ html",
-        "text / html",
-        "text/html other",
-        "text/html; x",
-        "text/html; x=",
-        "text/html; x=  ",
-        "text/html; = ",
-        "text/html;=",
-        "text/html; charset=\"\"",
-        "text/html; charset=\"",
-        "text/html; charset=\"\\",
-    };
-
-    for (invalids) |invalid| {
-        const mutable_input = try testing.arena_allocator.dupe(u8, invalid);
-        try testing.expectError(error.Invalid, Mime.parse(mutable_input));
-    }
-}
-
-test "Mime: parse common" {
-    defer testing.reset();
-
-    try expect(.{ .content_type = .{ .text_xml = {} } }, "text/xml");
-    try expect(.{ .content_type = .{ .text_html = {} } }, "text/html");
-    try expect(.{ .content_type = .{ .text_plain = {} } }, "text/plain");
-
-    try expect(.{ .content_type = .{ .text_xml = {} } }, "text/xml;");
-    try expect(.{ .content_type = .{ .text_html = {} } }, "text/html;");
-    try expect(.{ .content_type = .{ .text_plain = {} } }, "text/plain;");
-
-    try expect(.{ .content_type = .{ .text_xml = {} } }, "  \ttext/xml");
-    try expect(.{ .content_type = .{ .text_html = {} } }, "text/html   ");
-    try expect(.{ .content_type = .{ .text_plain = {} } }, "text/plain \t\t");
-
-    try expect(.{ .content_type = .{ .text_xml = {} } }, "TEXT/xml");
-    try expect(.{ .content_type = .{ .text_html = {} } }, "text/Html");
-    try expect(.{ .content_type = .{ .text_plain = {} } }, "TEXT/PLAIN");
-
-    try expect(.{ .content_type = .{ .text_xml = {} } }, " TeXT/xml");
-    try expect(.{ .content_type = .{ .text_html = {} } }, "teXt/HtML  ;");
-    try expect(.{ .content_type = .{ .text_plain = {} } }, "tExT/PlAiN;");
-
-    try expect(.{ .content_type = .{ .text_javascript = {} } }, "text/javascript");
-    try expect(.{ .content_type = .{ .text_javascript = {} } }, "Application/JavaScript");
-    try expect(.{ .content_type = .{ .text_javascript = {} } }, "application/x-javascript");
-
-    try expect(.{ .content_type = .{ .application_json = {} } }, "application/json");
-    try expect(.{ .content_type = .{ .text_css = {} } }, "text/css");
-}
-
-test "Mime: parse uncommon" {
-    defer testing.reset();
-
-    const text_csv = Expectation{
-        .content_type = .{ .other = .{ .type = "text", .sub_type = "csv" } },
-    };
-    try expect(text_csv, "text/csv");
-    try expect(text_csv, "text/csv;");
-    try expect(text_csv, "  text/csv\t  ");
-    try expect(text_csv, "  text/csv\t  ;");
-
-    try expect(
-        .{ .content_type = .{ .other = .{ .type = "text", .sub_type = "csv" } } },
-        "Text/CSV",
-    );
-}
-
-test "Mime: parse charset" {
-    defer testing.reset();
-
-    try expect(.{
-        .content_type = .{ .text_xml = {} },
-        .charset = "utf-8",
-        .params = "charset=utf-8",
-    }, "text/xml; charset=utf-8");
-
-    try expect(.{
-        .content_type = .{ .text_xml = {} },
-        .charset = "utf-8",
-        .params = "charset=\"utf-8\"",
-    }, "text/xml;charset=\"UTF-8\"");
-
-    try expect(.{
-        .content_type = .{ .text_html = {} },
-        .charset = "iso-8859-1",
-        .params = "charset=\"iso-8859-1\"",
-    }, "text/html; charset=\"iso-8859-1\"");
-
-    try expect(.{
-        .content_type = .{ .text_html = {} },
-        .charset = "iso-8859-1",
-        .params = "charset=\"iso-8859-1\"",
-    }, "text/html; charset=\"ISO-8859-1\"");
-
-    try expect(.{
-        .content_type = .{ .text_xml = {} },
-        .charset = "custom-non-standard-charset-value",
-        .params = "charset=\"custom-non-standard-charset-value\"",
-    }, "text/xml;charset=\"custom-non-standard-charset-value\"");
-}
-
-test "Mime: isHTML" {
-    defer testing.reset();
-
-    const assert = struct {
-        fn assert(expected: bool, input: []const u8) !void {
-            const mutable_input = try testing.arena_allocator.dupe(u8, input);
-            var mime = try Mime.parse(mutable_input);
-            try testing.expectEqual(expected, mime.isHTML());
-        }
-    }.assert;
-    try assert(true, "text/html");
-    try assert(true, "text/html;");
-    try assert(true, "text/html; charset=utf-8");
-    try assert(false, "text/htm"); // htm not html
-    try assert(false, "text/plain");
-    try assert(false, "over/9000");
-}
-
-test "Mime: sniff" {
-    try testing.expectEqual(null, Mime.sniff(""));
-    try testing.expectEqual(null, Mime.sniff("<htm"));
-    try testing.expectEqual(null, Mime.sniff("<html!"));
-    try testing.expectEqual(null, Mime.sniff("<a_"));
-    try testing.expectEqual(null, Mime.sniff("<!doctype html"));
-    try testing.expectEqual(null, Mime.sniff("<!doctype  html>"));
-    try testing.expectEqual(null, Mime.sniff("\n  <!doctype  html>"));
-    try testing.expectEqual(null, Mime.sniff("\n \t <font/>"));
-
-    const expectHTML = struct {
-        fn expect(input: []const u8) !void {
-            try testing.expectEqual(.text_html, std.meta.activeTag(Mime.sniff(input).?.content_type));
-        }
-    }.expect;
-
-    try expectHTML("<!doctype html ");
-    try expectHTML("\n  \t    <!DOCTYPE HTML ");
-
-    try expectHTML("<html ");
-    try expectHTML("\n  \t    <HtmL> even more stufff");
-
-    try expectHTML("<script>");
-    try expectHTML("\n  \t    <SCRIpt >alert(document.cookies)</script>");
-
-    try expectHTML("<iframe>");
-    try expectHTML(" \t    <ifRAME >");
-
-    try expectHTML("<h1>");
-    try expectHTML("  <H1>");
-
-    try expectHTML("<div>");
-    try expectHTML("\n\r\r  <DiV>");
-
-    try expectHTML("<font>");
-    try expectHTML("  <fonT>");
-
-    try expectHTML("<table>");
-    try expectHTML("\t\t<TAblE>");
-
-    try expectHTML("<a>");
-    try expectHTML("\n\n<A>");
-
-    try expectHTML("<style>");
-    try expectHTML("    \n\t <STyLE>");
-
-    try expectHTML("<title>");
-    try expectHTML("    \n\t <TITLE>");
-
-    try expectHTML("<b>");
-    try expectHTML("    \n\t <B>");
-
-    try expectHTML("<body>");
-    try expectHTML("    \n\t <BODY>");
-
-    try expectHTML("<br>");
-    try expectHTML("    \n\t <BR>");
-
-    try expectHTML("<p>");
-    try expectHTML("    \n\t <P>");
-
-    try expectHTML("<!-->");
-    try expectHTML("    \n\t <!-->");
-}
-
-const Expectation = struct {
-    content_type: Mime.ContentType,
-    params: []const u8 = "",
-    charset: ?[]const u8 = null,
-};
-
-fn expect(expected: Expectation, input: []const u8) !void {
-    const mutable_input = try testing.arena_allocator.dupe(u8, input);
-
-    const actual = try Mime.parse(mutable_input);
-    try testing.expectEqual(
-        std.meta.activeTag(expected.content_type),
-        std.meta.activeTag(actual.content_type),
-    );
-
-    switch (expected.content_type) {
-        .other => |e| {
-            const a = actual.content_type.other;
-            try testing.expectEqual(e.type, a.type);
-            try testing.expectEqual(e.sub_type, a.sub_type);
-        },
-        else => {}, // already asserted above
-    }
-
-    try testing.expectEqual(expected.params, actual.params);
-
-    if (expected.charset) |ec| {
-        // We remove the null characters for testing purposes here.
-        try testing.expectEqual(ec, actual.charsetString()[0..ec.len]);
-    } else {
-        const m: Mime = .unknown;
-        try testing.expectEqual(m.charsetString(), actual.charsetString());
-    }
-}
--- a/src/browser/Page.zig
+++ b/src/browser/Page.zig
--- a/src/browser/Renderer.zig
+++ b/src/browser/Renderer.zig
@@ -1,109 +0,0 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const parser = @import("netsurf.zig");
-
-const Allocator = std.mem.Allocator;
-
-const Renderer = @This();
-
-allocator: Allocator,
-
-// key is a @ptrFromInt of the element
-// value is the index position
-positions: std.AutoHashMapUnmanaged(u64, u32),
-
-// given an index, get the element
-elements: std.ArrayListUnmanaged(u64),
-
-const Element = @import("dom/element.zig").Element;
-
-// we expect allocator to be an arena
-pub fn init(allocator: Allocator) Renderer {
-    return .{
-        .elements = .{},
-        .positions = .{},
-        .allocator = allocator,
-    };
-}
-
-// The DOMRect is always relative to the viewport, not the document the element belongs to.
-// Element that are not part of the main document, either detached or in a shadow DOM should not call this function.
-pub fn getRect(self: *Renderer, e: *parser.Element) !Element.DOMRect {
-    var elements = &self.elements;
-    const gop = try self.positions.getOrPut(self.allocator, @intFromPtr(e));
-    var x: u32 = gop.value_ptr.*;
-    if (gop.found_existing == false) {
-        x = @intCast(elements.items.len);
-        try elements.append(self.allocator, @intFromPtr(e));
-        gop.value_ptr.* = x;
-    }
-
-    const _x: f64 = @floatFromInt(x);
-    const y: f64 = 0.0;
-    const w: f64 = 1.0;
-    const h: f64 = 1.0;
-
-    return .{
-        .x = _x,
-        .y = y,
-        .width = w,
-        .height = h,
-        .left = _x,
-        .top = y,
-        .right = _x + w,
-        .bottom = y + h,
-    };
-}
-
-pub fn boundingRect(self: *const Renderer) Element.DOMRect {
-    const x: f64 = 0.0;
-    const y: f64 = 0.0;
-    const w: f64 = @floatFromInt(self.width());
-    const h: f64 = @floatFromInt(self.width());
-
-    return .{
-        .x = x,
-        .y = y,
-        .width = w,
-        .height = h,
-        .left = x,
-        .top = y,
-        .right = x + w,
-        .bottom = y + h,
-    };
-}
-
-pub fn width(self: *const Renderer) u32 {
-    return @max(@as(u32, @intCast(self.elements.items.len)), 1); // At least 1 pixel even if empty
-}
-
-pub fn height(_: *const Renderer) u32 {
-    return 1;
-}
-
-pub fn getElementAtPosition(self: *const Renderer, x: i32, y: i32) ?*parser.Element {
-    if (y != 0 or x < 0) {
-        return null;
-    }
-
-    const elements = self.elements.items;
-    return if (x < elements.len) @ptrFromInt(elements[@intCast(x)]) else null;
-}
--- a/src/browser/Scheduler.zig
+++ b/src/browser/Scheduler.zig
@@ -1,95 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-
-const log = @import("../log.zig");
-const timestamp = @import("../datetime.zig").milliTimestamp;
-
-const IS_DEBUG = builtin.mode == .Debug;
-
-const Queue = std.PriorityQueue(Task, void, struct {
-    fn compare(_: void, a: Task, b: Task) std.math.Order {
-        return std.math.order(a.run_at, b.run_at);
-    }
-}.compare);
-
-const Scheduler = @This();
-
-low_priority: Queue,
-high_priority: Queue,
-
-pub fn init(allocator: std.mem.Allocator) Scheduler {
-    return .{
-        .low_priority = Queue.init(allocator, {}),
-        .high_priority = Queue.init(allocator, {}),
-    };
-}
-
-pub fn reset(self: *Scheduler) void {
-    self.low_priority.cap = 0;
-    self.low_priority.items.len = 0;
-
-    self.high_priority.cap = 0;
-    self.high_priority.items.len = 0;
-}
-
-const AddOpts = struct {
-    name: []const u8 = "",
-    low_priority: bool = false,
-};
-pub fn add(self: *Scheduler, ctx: *anyopaque, cb: Callback, run_in_ms: u32, opts: AddOpts) !void {
-    if (comptime IS_DEBUG) {
-        log.debug(.scheduler, "scheduler.add", .{ .name = opts.name, .run_in_ms = run_in_ms, .low_priority = opts.low_priority });
-    }
-    var queue = if (opts.low_priority) &self.low_priority else &self.high_priority;
-    return queue.add(.{
-        .ctx = ctx,
-        .callback = cb,
-        .name = opts.name,
-        .run_at = timestamp(.monotonic) + run_in_ms,
-    });
-}
-
-pub fn run(self: *Scheduler) !?u64 {
-    _ = try self.runQueue(&self.low_priority);
-    return self.runQueue(&self.high_priority);
-}
-
-fn runQueue(self: *Scheduler, queue: *Queue) !?u64 {
-    if (queue.count() == 0) {
-        return null;
-    }
-
-    const now = timestamp(.monotonic);
-
-    while (queue.peek()) |*task_| {
-        if (task_.run_at > now) {
-            return @intCast(task_.run_at - now);
-        }
-        var task = queue.remove();
-        if (comptime IS_DEBUG) {
-            log.debug(.scheduler, "scheduler.runTask", .{ .name = task.name });
-        }
-
-        const repeat_in_ms = task.callback(task.ctx) catch |err| {
-            log.warn(.scheduler, "task.callback", .{ .name = task.name, .err = err });
-            continue;
-        };
-
-        if (repeat_in_ms) |ms| {
-            // Task cannot be repeated immediately, and they should know that
-            std.debug.assert(ms != 0);
-            task.run_at = now + ms;
-            try self.low_priority.add(task);
-        }
-    }
-    return null;
-}
-
-const Task = struct {
-    run_at: u64,
-    ctx: *anyopaque,
-    name: []const u8,
-    callback: Callback,
-};
-
-const Callback = *const fn (ctx: *anyopaque) anyerror!?u32;
--- a/src/browser/ScriptManager.zig
+++ b/src/browser/ScriptManager.zig
--- a/src/browser/Session.zig
+++ b/src/browser/Session.zig
@@ -1,197 +0,0 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-
-const log = @import("../log.zig");
-
-const js = @import("js/js.zig");
-const storage = @import("webapi/storage/storage.zig");
-
-const Page = @import("Page.zig");
-const Browser = @import("Browser.zig");
-
-const Allocator = std.mem.Allocator;
-const NavigateOpts = Page.NavigateOpts;
-
-// Session is like a browser's tab.
-// It owns the js env and the loader for all the pages of the session.
-// You can create successively multiple pages for a session, but you must
-// deinit a page before running another one.
-const Session = @This();
-
-browser: *Browser,
-
-// Used to create our Inspector and in the BrowserContext.
-arena: Allocator,
-
-// The page's arena is unsuitable for data that has to existing while
-// navigating from one page to another. For example, if we're clicking
-// on an HREF, the URL exists in the original page (where the click
-// originated) but also has to exist in the new page.
-// While we could use the Session's arena, this could accumulate a lot of
-// memory if we do many navigation events. The `transfer_arena` is meant to
-// bridge the gap: existing long enough to store any data needed to end one
-// page and start another.
-transfer_arena: Allocator,
-
-executor: js.ExecutionWorld,
-cookie_jar: storage.Jar,
-storage_shed: storage.Shed,
-
-page: ?*Page = null,
-
-// If the current page want to navigate to a new page
-//  (form submit, link click, top.location = xxx)
-// the details are stored here so that, on the next call to session.wait
-// we can destroy the current page and start a new one.
-queued_navigation: ?QueuedNavigation,
-
-pub fn init(self: *Session, browser: *Browser) !void {
-    var executor = try browser.env.newExecutionWorld();
-    errdefer executor.deinit();
-
-    const allocator = browser.app.allocator;
-    self.* = .{
-        .browser = browser,
-        .executor = executor,
-        .storage_shed = .{},
-        .queued_navigation = null,
-        .arena = browser.session_arena.allocator(),
-        .cookie_jar = storage.Jar.init(allocator),
-        .transfer_arena = browser.transfer_arena.allocator(),
-    };
-}
-
-pub fn deinit(self: *Session) void {
-    if (self.page != null) {
-        self.removePage();
-    }
-    self.cookie_jar.deinit();
-    self.storage_shed.deinit(self.browser.app.allocator);
-    self.executor.deinit();
-}
-
-// NOTE: the caller is not the owner of the returned value,
-// the pointer on Page is just returned as a convenience
-pub fn createPage(self: *Session) !*Page {
-    std.debug.assert(self.page == null);
-
-    const page_arena = &self.browser.page_arena;
-    _ = page_arena.reset(.{ .retain_with_limit = 1 * 1024 * 1024 });
-
-    self.page = try Page.init(page_arena.allocator(), self.browser.call_arena.allocator(), self);
-    const page = self.page.?;
-
-    log.debug(.browser, "create page", .{});
-    // start JS env
-    // Inform CDP the main page has been created such that additional context for other Worlds can be created as well
-    self.browser.notification.dispatch(.page_created, page);
-
-    return page;
-}
-
-pub fn removePage(self: *Session) void {
-    // Inform CDP the page is going to be removed, allowing other worlds to remove themselves before the main one
-    self.browser.notification.dispatch(.page_remove, .{});
-
-    std.debug.assert(self.page != null);
-
-    // RemoveJsContext() will execute the destructor of any type that
-    // registered a destructor (e.g. XMLHttpRequest).
-    // Should be called before we deinit the page, because these objects
-    // could be referencing it.
-    self.executor.removeContext();
-
-    self.page.?.deinit();
-    self.page = null;
-
-    log.debug(.browser, "remove page", .{});
-}
-
-pub fn currentPage(self: *Session) ?*Page {
-    return self.page orelse return null;
-}
-
-pub const WaitResult = enum {
-    done,
-    no_page,
-    extra_socket,
-};
-
-pub fn wait(self: *Session, wait_ms: u32) WaitResult {
-    _ = self.processQueuedNavigation() catch {
-        // There was an error processing the queue navigation. This already
-        // logged the error, just return.
-        return .done;
-    };
-
-    if (self.page) |page| {
-        return page.wait(wait_ms);
-    }
-    return .no_page;
-}
-
-pub fn fetchWait(self: *Session, wait_ms: u32) void {
-    while (true) {
-        const page = self.page orelse return;
-        _ = page.wait(wait_ms);
-        const navigated = self.processQueuedNavigation() catch {
-            // There was an error processing the queue navigation. This already
-            // logged the error, just return.
-            return;
-        };
-
-        if (navigated == false) {
-            return;
-        }
-    }
-}
-
-fn processQueuedNavigation(self: *Session) !bool {
-    const qn = self.queued_navigation orelse return false;
-    // This was already aborted on the page, but it would be pretty
-    // bad if old requests went to the new page, so let's make double sure
-    self.browser.http_client.abort();
-
-    // Page.navigateFromWebAPI terminatedExecution. If we don't resume
-    // it before doing a shutdown we'll get an error.
-    self.executor.resumeExecution();
-    self.removePage();
-    self.queued_navigation = null;
-
-    const page = self.createPage() catch |err| {
-        log.err(.browser, "queued navigation page error", .{
-            .err = err,
-            .url = qn.url,
-        });
-        return err;
-    };
-
-    page.navigate(qn.url, qn.opts) catch |err| {
-        log.err(.browser, "queued navigation error", .{ .err = err, .url = qn.url });
-        return err;
-    };
-
-    return true;
-}
-
-const QueuedNavigation = struct {
-    url: [:0]const u8,
-    opts: NavigateOpts,
-};
--- a/src/browser/State.zig
+++ b/src/browser/State.zig
@@ -0,0 +1,76 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// Sometimes we need to extend libdom. For example, its HTMLDocument doesn't
+// have a readyState. We have a couple different options, such as making the
+// correction in libdom directly. Another option stems from the fact that every
+// libdom node has an opaque embedder_data field. This is the struct that we
+// lazily load into that field.
+//
+// It didn't originally start off as a collection of every single extension, but
+// this quickly proved necessary, since different fields are needed on the same
+// data at different levels of the prototype chain. This isn't memory efficient.
+
+const Env = @import("env.zig").Env;
+const parser = @import("netsurf.zig");
+const DataSet = @import("html/DataSet.zig");
+const ShadowRoot = @import("dom/shadow_root.zig").ShadowRoot;
+const StyleSheet = @import("cssom/stylesheet.zig").StyleSheet;
+const CSSStyleDeclaration = @import("cssom/css_style_declaration.zig").CSSStyleDeclaration;
+
+// for HTMLScript (but probably needs to be added to more)
+onload: ?Env.Function = null,
+onerror: ?Env.Function = null,
+
+// for HTMLElement
+style: CSSStyleDeclaration = .empty,
+dataset: ?DataSet = null,
+template_content: ?*parser.DocumentFragment = null,
+
+// For dom/element
+shadow_root: ?*ShadowRoot = null,
+
+// for html/document
+ready_state: ReadyState = .loading,
+
+// for html/HTMLStyleElement
+style_sheet: ?*StyleSheet = null,
+
+// for dom/document
+active_element: ?*parser.Element = null,
+
+// for HTMLSelectElement
+// By default, if no option is explicitly selected, the first option should
+// be selected. However, libdom doesn't do this, and it sets the
+// selectedIndex to -1, which is a valid value for "nothing selected".
+// Therefore, when libdom says the selectedIndex == -1, we don't know if
+// it means that nothing is selected, or if the first option is selected by
+// default.
+// There are cases where this won't work, but when selectedIndex is
+// explicitly set, we set this boolean flag. Then, when we're getting then
+// selectedIndex, if this flag is == false, which is to say that if
+// selectedIndex hasn't been explicitly set AND if we have at least 1 option
+// AND if it isn't a multi select, we can make the 1st item selected by
+// default (by returning selectedIndex == 0).
+explicit_index_set: bool = false,
+
+const ReadyState = enum {
+    loading,
+    interactive,
+    complete,
+};
--- a/src/browser/URL.zig
+++ b/src/browser/URL.zig
@@ -1,393 +0,0 @@
-const std = @import("std");
-const Allocator = std.mem.Allocator;
-
-const ResolveOpts = struct {
-    always_dupe: bool = false,
-};
-// path is anytype, so that it can be used with both []const u8 and [:0]const u8
-pub fn resolve(allocator: Allocator, base: [:0]const u8, path: anytype, comptime opts: ResolveOpts) ![:0]const u8 {
-    const PT = @TypeOf(path);
-    if (base.len == 0 or isCompleteHTTPUrl(path)) {
-        if (comptime opts.always_dupe or !isNullTerminated(PT)) {
-            return allocator.dupeZ(u8, path);
-        }
-        return path;
-    }
-
-    if (path.len == 0) {
-        if (comptime opts.always_dupe) {
-            return allocator.dupeZ(u8, base);
-        }
-        return base;
-    }
-
-    if (path[0] == '?') {
-        const base_path_end = std.mem.indexOfAny(u8, base, "?#") orelse base.len;
-        return std.mem.joinZ(allocator, "", &.{ base[0..base_path_end], path });
-    }
-    if (path[0] == '#') {
-        const base_fragment_start = std.mem.indexOfScalar(u8, base, '#') orelse base.len;
-        return std.mem.joinZ(allocator, "", &.{ base[0..base_fragment_start], path });
-    }
-
-    if (std.mem.startsWith(u8, path, "//")) {
-        // network-path reference
-        const index = std.mem.indexOfScalar(u8, base, ':') orelse {
-            if (comptime isNullTerminated(PT)) {
-                return path;
-            }
-            return allocator.dupeZ(u8, path);
-        };
-        const protocol = base[0 .. index + 1];
-        return std.mem.joinZ(allocator, "", &.{ protocol, path });
-    }
-
-    const scheme_end = std.mem.indexOf(u8, base, "://");
-    const authority_start = if (scheme_end) |end| end + 3 else 0;
-    const path_start = std.mem.indexOfScalarPos(u8, base, authority_start, '/') orelse base.len;
-
-    if (path[0] == '/') {
-        return std.mem.joinZ(allocator, "", &.{ base[0..path_start], path });
-    }
-
-    var normalized_base: []const u8 = base;
-    if (std.mem.lastIndexOfScalar(u8, normalized_base[authority_start..], '/')) |pos| {
-        normalized_base = normalized_base[0 .. pos + authority_start];
-    }
-
-    // trailing space so that we always have space to append the null terminator
-    var out = try std.mem.join(allocator, "", &.{ normalized_base, "/", path, " " });
-    const end = out.len - 1;
-
-    const path_marker = path_start + 1;
-
-    // Strip out ./ and ../. This is done in-place, because doing so can
-    // only ever make `out` smaller. After this, `out` cannot be freed by
-    // an allocator, which is ok, because we expect allocator to be an arena.
-    var in_i: usize = 0;
-    var out_i: usize = 0;
-    while (in_i < end) {
-        if (std.mem.startsWith(u8, out[in_i..], "./")) {
-            in_i += 2;
-            continue;
-        }
-
-        if (std.mem.startsWith(u8, out[in_i..], "../")) {
-            std.debug.assert(out[out_i - 1] == '/');
-
-            if (out_i > path_marker) {
-                // go back before the /
-                out_i -= 2;
-                while (out_i > 1 and out[out_i - 1] != '/') {
-                    out_i -= 1;
-                }
-            } else {
-                // if out_i == path_marker, than we've reached the start of
-                // the path. We can't ../ any more. E.g.:
-                //    http://www.example.com/../hello.
-                // You might think that's an error, but, at least with
-                //     new URL('../hello', 'http://www.example.com/')
-                // it just ignores the extra ../
-            }
-            in_i += 3;
-            continue;
-        }
-
-        out[out_i] = out[in_i];
-        in_i += 1;
-        out_i += 1;
-    }
-
-    // we always have an extra space
-    out[out_i] = 0;
-    return out[0..out_i :0];
-}
-
-fn isNullTerminated(comptime value: type) bool {
-    return @typeInfo(value).pointer.sentinel_ptr != null;
-}
-
-pub fn isCompleteHTTPUrl(url: []const u8) bool {
-    if (url.len < 6) {
-        return false;
-    }
-
-    // very common case
-    if (url[0] == '/') {
-        return false;
-    }
-
-    return std.ascii.startsWithIgnoreCase(url, "https://") or
-        std.ascii.startsWithIgnoreCase(url, "http://") or
-        std.ascii.startsWithIgnoreCase(url, "ftp://");
-}
-
-pub fn getUsername(raw: [:0]const u8) []const u8 {
-    const user_info = getUserInfo(raw) orelse return "";
-    const pos = std.mem.indexOfScalarPos(u8, user_info, 0, ':') orelse return user_info;
-    return user_info[0..pos];
-}
-
-pub fn getPassword(raw: [:0]const u8) []const u8 {
-    const user_info = getUserInfo(raw) orelse return "";
-    const pos = std.mem.indexOfScalarPos(u8, user_info, 0, ':') orelse return "";
-    return user_info[pos + 1 ..];
-}
-
-pub fn getPathname(raw: [:0]const u8) []const u8 {
-    const protocol_end = std.mem.indexOf(u8, raw, "://") orelse 0;
-    const path_start = std.mem.indexOfScalarPos(u8, raw, if (protocol_end > 0) protocol_end + 3 else 0, '/') orelse raw.len;
-
-    const query_or_hash_start = std.mem.indexOfAnyPos(u8, raw, path_start, "?#") orelse raw.len;
-
-    if (path_start >= query_or_hash_start) {
-        if (std.mem.indexOf(u8, raw, "://") != null) return "/";
-        return "";
-    }
-
-    return raw[path_start..query_or_hash_start];
-}
-
-pub fn getProtocol(raw: [:0]const u8) []const u8 {
-    const pos = std.mem.indexOfScalarPos(u8, raw, 0, ':') orelse return "";
-    return raw[0 .. pos + 1];
-}
-
-pub fn getHostname(raw: [:0]const u8) []const u8 {
-    const host = getHost(raw);
-    const pos = std.mem.lastIndexOfScalar(u8, host, ':') orelse return host;
-    return host[0..pos];
-}
-
-pub fn getPort(raw: [:0]const u8) []const u8 {
-    const host = getHost(raw);
-    const pos = std.mem.lastIndexOfScalar(u8, host, ':') orelse return "";
-
-    if (pos + 1 >= host.len) {
-        return "";
-    }
-
-    for (host[pos + 1 ..]) |c| {
-        if (c < '0' or c > '9') {
-            return "";
-        }
-    }
-
-    return host[pos + 1 ..];
-}
-
-pub fn getSearch(raw: [:0]const u8) []const u8 {
-    const pos = std.mem.indexOfScalarPos(u8, raw, 0, '?') orelse return "";
-    const query_part = raw[pos..];
-
-    if (std.mem.indexOfScalarPos(u8, query_part, 0, '#')) |fragment_start| {
-        return query_part[0..fragment_start];
-    }
-
-    return query_part;
-}
-
-pub fn getHash(raw: [:0]const u8) []const u8 {
-    const start = std.mem.indexOfScalarPos(u8, raw, 0, '#') orelse return "";
-    return raw[start..];
-}
-
-pub fn getOrigin(allocator: Allocator, raw: [:0]const u8) !?[]const u8 {
-    const port = getPort(raw);
-    const protocol = getProtocol(raw);
-    const hostname = getHostname(raw);
-
-    const p = std.meta.stringToEnum(KnownProtocol, getProtocol(raw)) orelse return null;
-
-    const include_port = blk: {
-        if (port.len == 0) {
-            break :blk false;
-        }
-        if (p == .@"https:" and std.mem.eql(u8, port, "443")) {
-            break :blk false;
-        }
-        if (p == .@"http:" and std.mem.eql(u8, port, "80")) {
-            break :blk false;
-        }
-        break :blk true;
-    };
-
-    if (include_port) {
-        return try std.fmt.allocPrint(allocator, "{s}//{s}:{s}", .{ protocol, hostname, port });
-    }
-    return try std.fmt.allocPrint(allocator, "{s}//{s}", .{ protocol, hostname });
-}
-
-fn getUserInfo(raw: [:0]const u8) ?[]const u8 {
-    const scheme_end = std.mem.indexOf(u8, raw, "://") orelse return null;
-    const authority_start = scheme_end + 3;
-
-    const pos = std.mem.indexOfScalar(u8, raw[authority_start..], '@') orelse return null;
-    const path_start = std.mem.indexOfScalarPos(u8, raw, authority_start, '/') orelse raw.len;
-
-    const full_pos = authority_start + pos;
-    if (full_pos < path_start) {
-        return raw[authority_start..full_pos];
-    }
-
-    return null;
-}
-
-fn getHost(raw: [:0]const u8) []const u8 {
-    const scheme_end = std.mem.indexOf(u8, raw, "://") orelse return "";
-
-    var authority_start = scheme_end + 3;
-    if (std.mem.indexOf(u8, raw[authority_start..], "@")) |pos| {
-        authority_start += pos + 1;
-    }
-
-    const authority = raw[authority_start..];
-    const path_start = std.mem.indexOfAny(u8, authority, "/?#") orelse return authority;
-    return authority[0..path_start];
-}
-
-const KnownProtocol = enum {
-    @"http:",
-    @"https:",
-};
-
-const testing = @import("../testing.zig");
-test "URL: isCompleteHTTPUrl" {
-    try testing.expectEqual(true, isCompleteHTTPUrl("http://example.com/about"));
-    try testing.expectEqual(true, isCompleteHTTPUrl("HttP://example.com/about"));
-    try testing.expectEqual(true, isCompleteHTTPUrl("httpS://example.com/about"));
-    try testing.expectEqual(true, isCompleteHTTPUrl("HTTPs://example.com/about"));
-    try testing.expectEqual(true, isCompleteHTTPUrl("ftp://example.com/about"));
-
-    try testing.expectEqual(false, isCompleteHTTPUrl("/example.com"));
-    try testing.expectEqual(false, isCompleteHTTPUrl("../../about"));
-    try testing.expectEqual(false, isCompleteHTTPUrl("about"));
-}
-
-test "URL: resolve" {
-    defer testing.reset();
-
-    const Case = struct {
-        base: [:0]const u8,
-        path: [:0]const u8,
-        expected: [:0]const u8,
-    };
-
-    const cases = [_]Case{
-        .{
-            .base = "https://example/xyz/abc/123",
-            .path = "something.js",
-            .expected = "https://example/xyz/abc/something.js",
-        },
-        .{
-            .base = "https://example/xyz/abc/123",
-            .path = "/something.js",
-            .expected = "https://example/something.js",
-        },
-        .{
-            .base = "https://example/",
-            .path = "something.js",
-            .expected = "https://example/something.js",
-        },
-        .{
-            .base = "https://example/",
-            .path = "/something.js",
-            .expected = "https://example/something.js",
-        },
-        .{
-            .base = "https://example",
-            .path = "something.js",
-            .expected = "https://example/something.js",
-        },
-        .{
-            .base = "https://example",
-            .path = "abc/something.js",
-            .expected = "https://example/abc/something.js",
-        },
-        .{
-            .base = "https://example/nested",
-            .path = "abc/something.js",
-            .expected = "https://example/abc/something.js",
-        },
-        .{
-            .base = "https://example/nested/",
-            .path = "abc/something.js",
-            .expected = "https://example/nested/abc/something.js",
-        },
-        .{
-            .base = "https://example/nested/",
-            .path = "/abc/something.js",
-            .expected = "https://example/abc/something.js",
-        },
-        .{
-            .base = "https://example/nested/",
-            .path = "http://www.github.com/example/",
-            .expected = "http://www.github.com/example/",
-        },
-        .{
-            .base = "https://example/nested/",
-            .path = "",
-            .expected = "https://example/nested/",
-        },
-        .{
-            .base = "https://example/abc/aaa",
-            .path = "./hello/./world",
-            .expected = "https://example/abc/hello/world",
-        },
-        .{
-            .base = "https://example/abc/aaa/",
-            .path = "../hello",
-            .expected = "https://example/abc/hello",
-        },
-        .{
-            .base = "https://example/abc/aaa",
-            .path = "../hello",
-            .expected = "https://example/hello",
-        },
-        .{
-            .base = "https://example/abc/aaa/",
-            .path = "./.././.././hello",
-            .expected = "https://example/hello",
-        },
-        .{
-            .base = "some/page",
-            .path = "hello",
-            .expected = "some/hello",
-        },
-        .{
-            .base = "some/page/",
-            .path = "hello",
-            .expected = "some/page/hello",
-        },
-        .{
-            .base = "some/page/other",
-            .path = ".././hello",
-            .expected = "some/hello",
-        },
-        .{
-            .base = "https://www.example.com/hello/world",
-            .path = "//example/about",
-            .expected = "https://example/about",
-        },
-        .{
-            .base = "http:",
-            .path = "//example.com/over/9000",
-            .expected = "http://example.com/over/9000",
-        },
-        .{
-            .base = "https://example.com/",
-            .path = "../hello",
-            .expected = "https://example.com/hello",
-        },
-        .{
-            .base = "https://www.example.com/hello/world/",
-            .path = "../../../../example/about",
-            .expected = "https://www.example.com/example/about",
-        },
-    };
-
-    for (cases) |case| {
-        const result = try resolve(testing.arena_allocator, case.base, case.path, .{});
-        try testing.expectString(case.expected, result);
-    }
-}
--- a/src/browser/browser.zig
+++ b/src/browser/browser.zig
@@ -0,0 +1,120 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Allocator = std.mem.Allocator;
+const ArenaAllocator = std.heap.ArenaAllocator;
+
+const State = @import("State.zig");
+const Env = @import("env.zig").Env;
+const App = @import("../app.zig").App;
+const Session = @import("session.zig").Session;
+const Notification = @import("../notification.zig").Notification;
+
+const log = @import("../log.zig");
+
+const http = @import("../http/client.zig");
+
+// Browser is an instance of the browser.
+// You can create multiple browser instances.
+// A browser contains only one session.
+pub const Browser = struct {
+    env: *Env,
+    app: *App,
+    session: ?Session,
+    allocator: Allocator,
+    http_client: *http.Client,
+    page_arena: ArenaAllocator,
+    session_arena: ArenaAllocator,
+    transfer_arena: ArenaAllocator,
+    notification: *Notification,
+    state_pool: std.heap.MemoryPool(State),
+
+    pub fn init(app: *App) !Browser {
+        const allocator = app.allocator;
+
+        const env = try Env.init(allocator, app.platform, .{});
+        errdefer env.deinit();
+
+        const notification = try Notification.init(allocator, app.notification);
+        errdefer notification.deinit();
+
+        return .{
+            .app = app,
+            .env = env,
+            .session = null,
+            .allocator = allocator,
+            .notification = notification,
+            .http_client = &app.http_client,
+            .page_arena = ArenaAllocator.init(allocator),
+            .session_arena = ArenaAllocator.init(allocator),
+            .transfer_arena = ArenaAllocator.init(allocator),
+            .state_pool = std.heap.MemoryPool(State).init(allocator),
+        };
+    }
+
+    pub fn deinit(self: *Browser) void {
+        self.closeSession();
+        self.env.deinit();
+        self.page_arena.deinit();
+        self.session_arena.deinit();
+        self.transfer_arena.deinit();
+        self.notification.deinit();
+        self.state_pool.deinit();
+    }
+
+    pub fn newSession(self: *Browser) !*Session {
+        self.closeSession();
+        self.session = @as(Session, undefined);
+        const session = &self.session.?;
+        try Session.init(session, self);
+        return session;
+    }
+
+    pub fn closeSession(self: *Browser) void {
+        if (self.session) |*session| {
+            session.deinit();
+            self.session = null;
+            _ = self.session_arena.reset(.{ .retain_with_limit = 1 * 1024 * 1024 });
+            self.env.lowMemoryNotification();
+        }
+    }
+
+    pub fn runMicrotasks(self: *const Browser) void {
+        self.env.runMicrotasks();
+    }
+
+    pub fn runMessageLoop(self: *const Browser) void {
+        while (self.env.pumpMessageLoop()) {
+            log.debug(.browser, "pumpMessageLoop", .{});
+        }
+        self.env.runIdleTasks();
+    }
+};
+
+const testing = @import("../testing.zig");
+test "Browser" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    // this will crash if ICU isn't properly configured / ininitialized
+    try runner.testCases(&.{
+        .{ "new Intl.DateTimeFormat()", "[object Intl.DateTimeFormat]" },
+    }, .{});
+}
--- a/src/browser/console/console.zig
+++ b/src/browser/console/console.zig
@@ -0,0 +1,329 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const builtin = @import("builtin");
+
+const Allocator = std.mem.Allocator;
+const Page = @import("../page.zig").Page;
+const JsObject = @import("../env.zig").Env.JsObject;
+
+const log = if (builtin.is_test) &test_capture else @import("../../log.zig");
+
+pub const Console = struct {
+    // TODO: configurable writer
+    timers: std.StringHashMapUnmanaged(u32) = .{},
+    counts: std.StringHashMapUnmanaged(u32) = .{},
+
+    pub fn _lp(values: []JsObject, page: *Page) !void {
+        if (values.len == 0) {
+            return;
+        }
+        log.fatal(.console, "lightpanda", .{ .args = try serializeValues(values, page) });
+    }
+
+    pub fn _log(values: []JsObject, page: *Page) !void {
+        if (values.len == 0) {
+            return;
+        }
+        log.info(.console, "info", .{ .args = try serializeValues(values, page) });
+    }
+
+    pub fn _info(values: []JsObject, page: *Page) !void {
+        return _log(values, page);
+    }
+
+    pub fn _debug(values: []JsObject, page: *Page) !void {
+        if (values.len == 0) {
+            return;
+        }
+        log.debug(.console, "debug", .{ .args = try serializeValues(values, page) });
+    }
+
+    pub fn _warn(values: []JsObject, page: *Page) !void {
+        if (values.len == 0) {
+            return;
+        }
+        log.warn(.console, "warn", .{ .args = try serializeValues(values, page) });
+    }
+
+    pub fn _error(values: []JsObject, page: *Page) !void {
+        if (values.len == 0) {
+            return;
+        }
+
+        log.info(.console, "error", .{
+            .args = try serializeValues(values, page),
+            .stack = page.stackTrace() catch "???",
+        });
+    }
+
+    pub fn _clear() void {}
+
+    pub fn _count(self: *Console, label_: ?[]const u8, page: *Page) !void {
+        const label = label_ orelse "default";
+        const gop = try self.counts.getOrPut(page.arena, label);
+
+        var current: u32 = 0;
+        if (gop.found_existing) {
+            current = gop.value_ptr.*;
+        } else {
+            gop.key_ptr.* = try page.arena.dupe(u8, label);
+        }
+
+        const count = current + 1;
+        gop.value_ptr.* = count;
+
+        log.info(.console, "count", .{ .label = label, .count = count });
+    }
+
+    pub fn _countReset(self: *Console, label_: ?[]const u8) !void {
+        const label = label_ orelse "default";
+        const kv = self.counts.fetchRemove(label) orelse {
+            log.info(.console, "invalid counter", .{ .label = label });
+            return;
+        };
+        log.info(.console, "count reset", .{ .label = label, .count = kv.value });
+    }
+
+    pub fn _time(self: *Console, label_: ?[]const u8, page: *Page) !void {
+        const label = label_ orelse "default";
+        const gop = try self.timers.getOrPut(page.arena, label);
+
+        if (gop.found_existing) {
+            log.info(.console, "duplicate timer", .{ .label = label });
+            return;
+        }
+        gop.key_ptr.* = try page.arena.dupe(u8, label);
+        gop.value_ptr.* = timestamp();
+    }
+
+    pub fn _timeLog(self: *Console, label_: ?[]const u8) void {
+        const elapsed = timestamp();
+        const label = label_ orelse "default";
+        const start = self.timers.get(label) orelse {
+            log.info(.console, "invalid timer", .{ .label = label });
+            return;
+        };
+        log.info(.console, "timer", .{ .label = label, .elapsed = elapsed - start });
+    }
+
+    pub fn _timeStop(self: *Console, label_: ?[]const u8) void {
+        const elapsed = timestamp();
+        const label = label_ orelse "default";
+        const kv = self.timers.fetchRemove(label) orelse {
+            log.info(.console, "invalid timer", .{ .label = label });
+            return;
+        };
+
+        log.warn(.console, "timer stop", .{ .label = label, .elapsed = elapsed - kv.value });
+    }
+
+    pub fn _assert(assertion: JsObject, values: []JsObject, page: *Page) !void {
+        if (assertion.isTruthy()) {
+            return;
+        }
+        var serialized_values: []const u8 = "";
+        if (values.len > 0) {
+            serialized_values = try serializeValues(values, page);
+        }
+        log.info(.console, "assertion failed", .{ .values = serialized_values });
+    }
+
+    fn serializeValues(values: []JsObject, page: *Page) ![]const u8 {
+        if (values.len == 0) {
+            return "";
+        }
+
+        const arena = page.call_arena;
+        const separator = log.separator();
+        var arr: std.ArrayListUnmanaged(u8) = .{};
+
+        for (values, 1..) |value, i| {
+            try arr.appendSlice(arena, separator);
+            try arr.writer(arena).print("{d}: ", .{i});
+            const serialized = if (builtin.mode == .Debug) value.toDetailString() else value.toString();
+            try arr.appendSlice(arena, try serialized);
+        }
+        return arr.items;
+    }
+};
+
+fn timestamp() u32 {
+    const ts = std.posix.clock_gettime(std.posix.CLOCK.MONOTONIC) catch unreachable;
+    return @intCast(ts.sec);
+}
+
+var test_capture = TestCapture{};
+const testing = @import("../../testing.zig");
+test "Browser.Console" {
+    defer testing.reset();
+
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    {
+        try runner.testCases(&.{
+            .{ "console.log('a')", "undefined" },
+            .{ "console.warn('hello world', 23, true, new Object())", "undefined" },
+        }, .{});
+
+        const captured = test_capture.captured.items;
+        try testing.expectEqual("[info] args= 1: a", captured[0]);
+        try testing.expectEqual("[warn] args= 1: hello world 2: 23 3: true 4: #<Object>", captured[1]);
+    }
+
+    {
+        test_capture.reset();
+        try runner.testCases(&.{
+            .{ "console.countReset()", "undefined" },
+            .{ "console.count()", "undefined" },
+            .{ "console.count('teg')", "undefined" },
+            .{ "console.count('teg')", "undefined" },
+            .{ "console.count('teg')", "undefined" },
+            .{ "console.count()", "undefined" },
+            .{ "console.countReset('teg')", "undefined" },
+            .{ "console.countReset()", "undefined" },
+            .{ "console.count()", "undefined" },
+        }, .{});
+
+        const captured = test_capture.captured.items;
+        try testing.expectEqual("[invalid counter] label=default", captured[0]);
+        try testing.expectEqual("[count] label=default count=1", captured[1]);
+        try testing.expectEqual("[count] label=teg count=1", captured[2]);
+        try testing.expectEqual("[count] label=teg count=2", captured[3]);
+        try testing.expectEqual("[count] label=teg count=3", captured[4]);
+        try testing.expectEqual("[count] label=default count=2", captured[5]);
+        try testing.expectEqual("[count reset] label=teg count=3", captured[6]);
+        try testing.expectEqual("[count reset] label=default count=2", captured[7]);
+        try testing.expectEqual("[count] label=default count=1", captured[8]);
+    }
+
+    {
+        test_capture.reset();
+        try runner.testCases(&.{
+            .{ "console.assert(true)", "undefined" },
+            .{ "console.assert('a', 2, 3, 4)", "undefined" },
+            .{ "console.assert('')", "undefined" },
+            .{ "console.assert('', 'x', true)", "undefined" },
+            .{ "console.assert(false, 'x')", "undefined" },
+        }, .{});
+
+        const captured = test_capture.captured.items;
+        try testing.expectEqual("[assertion failed] values=", captured[0]);
+        try testing.expectEqual("[assertion failed] values= 1: x 2: true", captured[1]);
+        try testing.expectEqual("[assertion failed] values= 1: x", captured[2]);
+    }
+
+    {
+        test_capture.reset();
+        try runner.testCases(&.{
+            .{ "[1].forEach(console.log)", null },
+        }, .{});
+
+        const captured = test_capture.captured.items;
+        try testing.expectEqual("[info] args= 1: 1 2: 0 3: [1]", captured[0]);
+    }
+}
+
+const TestCapture = struct {
+    captured: std.ArrayListUnmanaged([]const u8) = .{},
+
+    fn separator(_: *const TestCapture) []const u8 {
+        return " ";
+    }
+
+    fn reset(self: *TestCapture) void {
+        self.captured = .{};
+    }
+
+    fn debug(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self.capture(scope, msg, args);
+    }
+
+    fn info(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self.capture(scope, msg, args);
+    }
+
+    fn warn(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self.capture(scope, msg, args);
+    }
+
+    fn err(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self.capture(scope, msg, args);
+    }
+
+    fn fatal(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self.capture(scope, msg, args);
+    }
+
+    fn capture(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) void {
+        self._capture(scope, msg, args) catch unreachable;
+    }
+
+    fn _capture(
+        self: *TestCapture,
+        comptime scope: @Type(.enum_literal),
+        comptime msg: []const u8,
+        args: anytype,
+    ) !void {
+        std.debug.assert(scope == .console);
+
+        const allocator = testing.arena_allocator;
+        var buf: std.ArrayListUnmanaged(u8) = .empty;
+        try buf.appendSlice(allocator, "[" ++ msg ++ "] ");
+
+        inline for (@typeInfo(@TypeOf(args)).@"struct".fields) |f| {
+            try buf.appendSlice(allocator, f.name);
+            try buf.append(allocator, '=');
+            try @import("../../log.zig").writeValue(.pretty, @field(args, f.name), buf.writer(allocator));
+            try buf.append(allocator, ' ');
+        }
+        self.captured.append(testing.arena_allocator, std.mem.trimRight(u8, buf.items, " ")) catch unreachable;
+    }
+};
--- a/src/browser/crypto/crypto.zig
+++ b/src/browser/crypto/crypto.zig
@@ -0,0 +1,97 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Env = @import("../env.zig").Env;
+const uuidv4 = @import("../../id.zig").uuidv4;
+
+// https://w3c.github.io/webcrypto/#crypto-interface
+pub const Crypto = struct {
+    _not_empty: bool = true,
+
+    pub fn _getRandomValues(_: *const Crypto, js_obj: Env.JsObject) !Env.JsObject {
+        var into = try js_obj.toZig(Crypto, "getRandomValues", RandomValues);
+        const buf = into.asBuffer();
+        if (buf.len > 65_536) {
+            return error.QuotaExceededError;
+        }
+        std.crypto.random.bytes(buf);
+        return js_obj;
+    }
+
+    pub fn _randomUUID(_: *const Crypto) [36]u8 {
+        var hex: [36]u8 = undefined;
+        uuidv4(&hex);
+        return hex;
+    }
+};
+
+const RandomValues = union(enum) {
+    int8: []i8,
+    uint8: []u8,
+    int16: []i16,
+    uint16: []u16,
+    int32: []i32,
+    uint32: []u32,
+    int64: []i64,
+    uint64: []u64,
+
+    fn asBuffer(self: RandomValues) []u8 {
+        return switch (self) {
+            .int8 => |b| (@as([]u8, @ptrCast(b)))[0..b.len],
+            .uint8 => |b| (@as([]u8, @ptrCast(b)))[0..b.len],
+            .int16 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 2],
+            .uint16 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 2],
+            .int32 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 4],
+            .uint32 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 4],
+            .int64 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 8],
+            .uint64 => |b| (@as([]u8, @ptrCast(b)))[0 .. b.len * 8],
+        };
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.Crypto" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "const a = crypto.randomUUID();", "undefined" },
+        .{ "const b = crypto.randomUUID();", "undefined" },
+        .{ "a.length;", "36" },
+        .{ "b.length;", "36" },
+        .{ "a == b;", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "try { crypto.getRandomValues(new BigUint64Array(8193)) } catch(e) { e.message == 'QuotaExceededError' }", "true" },
+        .{ "let r1 = new Int32Array(5)", "undefined" },
+        .{ "let r2 = crypto.getRandomValues(r1)", "undefined" },
+        .{ "new Set(r1).size", "5" },
+        .{ "new Set(r2).size", "5" },
+        .{ "r1.every((v, i) => v === r2[i])", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var r3 = new Uint8Array(16)", null },
+        .{ "let r4 = crypto.getRandomValues(r3)", "undefined" },
+        .{ "r4[6] = 10", null },
+        .{ "r4[6]", "10" },
+        .{ "r3[6]", "10" },
+    }, .{});
+}
--- a/src/browser/css/README.md
+++ b/src/browser/css/README.md
@@ -0,0 +1,218 @@
+# css
+
+Lightpanda css implements CSS selectors parsing and matching in Zig.
+This package is a port of the Go lib [andybalholm/cascadia](https://github.com/andybalholm/cascadia).
+
+## Usage
+
+### Query parser
+
+```zig
+const css = @import("css.zig");
+
+const selector = try css.parse(alloc, "h1", .{});
+defer selector.deinit(alloc);
+```
+
+### DOM tree match
+
+The lib expects a `Node` interface implementation to match your DOM tree.
+
+```zig
+pub const Node = struct {
+    pub fn firstChild(_: Node) !?Node {
+        return error.TODO;
+    }
+
+    pub fn lastChild(_: Node) !?Node {
+        return error.TODO;
+    }
+
+    pub fn nextSibling(_: Node) !?Node {
+        return error.TODO;
+    }
+
+    pub fn prevSibling(_: Node) !?Node {
+        return error.TODO;
+    }
+
+    pub fn parent(_: Node) !?Node {
+        return error.TODO;
+    }
+
+    pub fn isElement(_: Node) bool {
+        return false;
+    }
+
+    pub fn isDocument(_: Node) bool {
+        return false;
+    }
+
+    pub fn isComment(_: Node) bool {
+        return false;
+    }
+
+    pub fn isText(_: Node) bool {
+        return false;
+    }
+
+    pub fn isEmptyText(_: Node) !bool {
+        return error.TODO;
+    }
+
+    pub fn tag(_: Node) ![]const u8 {
+        return error.TODO;
+    }
+
+    pub fn attr(_: Node, _: []const u8) !?[]const u8 {
+        return error.TODO;
+    }
+
+    pub fn eql(_: Node, _: Node) bool {
+        return false;
+    }
+};
+```
+
+You also need do define a `Matcher` implementing a `match` function to
+accumulate the results.
+
+```zig
+const Matcher = struct {
+    const Nodes = std.ArrayList(Node);
+
+    nodes: Nodes,
+
+    fn init(alloc: std.mem.Allocator) Matcher {
+        return .{ .nodes = Nodes.init(alloc) };
+    }
+
+    fn deinit(m: *Matcher) void {
+        m.nodes.deinit();
+    }
+
+    pub fn match(m: *Matcher, n: Node) !void {
+        try m.nodes.append(n);
+    }
+};
+```
+
+Then you can use the lib itself.
+
+```zig
+var matcher = Matcher.init(alloc);
+defer matcher.deinit();
+
+try css.matchAll(selector, node, &matcher);
+_ = try css.matchFirst(selector, node, &matcher); // returns true if a node matched.
+```
+
+## Features
+
+* [x] parse query selector
+* [x] `matchAll`
+* [x] `matchFirst`
+* [ ] specificity
+
+### Selectors implemented
+
+#### Selectors
+
+* [x] Class selectors
+* [x] Id selectors
+* [x] Type selectors
+* [x] Universal selectors
+* [ ] Nesting selectors
+
+#### Combinators
+
+* [x] Child combinator
+* [ ] Column combinator
+* [x] Descendant combinator
+* [ ] Namespace combinator
+* [x] Next-sibling combinator
+* [x] Selector list combinator
+* [x] Subsequent-sibling combinator
+
+#### Attribute
+
+* [x] `[attr]`
+* [x] `[attr=value]`
+* [x] `[attr|=value]`
+* [x] `[attr^=value]`
+* [x] `[attr$=value]`
+* [ ] `[attr*=value]`
+* [x] `[attr operator value i]`
+* [ ] `[attr operator value s]`
+
+#### Pseudo classes
+
+* [ ] `:active`
+* [ ] `:any-link`
+* [ ] `:autofill`
+* [ ] `:blank Experimental`
+* [x] `:checked`
+* [ ] `:current Experimental`
+* [ ] `:default`
+* [ ] `:defined`
+* [ ] `:dir() Experimental`
+* [x] `:disabled`
+* [x] `:empty`
+* [x] `:enabled`
+* [ ] `:first`
+* [x] `:first-child`
+* [x] `:first-of-type`
+* [ ] `:focus`
+* [ ] `:focus-visible`
+* [ ] `:focus-within`
+* [ ] `:fullscreen`
+* [ ] `:future Experimental`
+* [x] `:has() Experimental`
+* [ ] `:host`
+* [ ] `:host()`
+* [ ] `:host-context() Experimental`
+* [ ] `:hover`
+* [ ] `:indeterminate`
+* [ ] `:in-range`
+* [ ] `:invalid`
+* [ ] `:is()`
+* [x] `:lang()`
+* [x] `:last-child`
+* [x] `:last-of-type`
+* [ ] `:left`
+* [x] `:link`
+* [ ] `:local-link Experimental`
+* [ ] `:modal`
+* [x] `:not()`
+* [x] `:nth-child()`
+* [x] `:nth-last-child()`
+* [x] `:nth-last-of-type()`
+* [x] `:nth-of-type()`
+* [x] `:only-child`
+* [x] `:only-of-type`
+* [ ] `:optional`
+* [ ] `:out-of-range`
+* [ ] `:past Experimental`
+* [ ] `:paused`
+* [ ] `:picture-in-picture`
+* [ ] `:placeholder-shown`
+* [ ] `:playing`
+* [ ] `:read-only`
+* [ ] `:read-write`
+* [ ] `:required`
+* [ ] `:right`
+* [x] `:root`
+* [ ] `:scope`
+* [ ] `:state() Experimental`
+* [ ] `:target`
+* [ ] `:target-within Experimental`
+* [ ] `:user-invalid Experimental`
+* [ ] `:valid`
+* [ ] `:visited`
+* [ ] `:where()`
+* [ ] `:contains()`
+* [ ] `:containsown()`
+* [ ] `:matched()`
+* [ ] `:matchesown()`
+* [x] `:root`
+
--- a/src/browser/css/css.zig
+++ b/src/browser/css/css.zig
@@ -0,0 +1,201 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// CSS Selector parser and query
+// This package is a rewrite in Zig of Cascadia CSS Selector parser.
+// see https://github.com/andybalholm/cascadia
+const std = @import("std");
+const Selector = @import("selector.zig").Selector;
+const parser = @import("parser.zig");
+
+pub const Interfaces = .{
+    Css,
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/CSS
+pub const Css = struct {
+    _not_empty: bool = true,
+
+    pub fn _supports(_: *Css, _: []const u8, _: ?[]const u8) bool {
+        // TODO: Actually respond with which CSS features we support.
+        return true;
+    }
+};
+
+// parse parse a selector string and returns the parsed result or an error.
+pub fn parse(alloc: std.mem.Allocator, s: []const u8, opts: parser.ParseOptions) parser.ParseError!Selector {
+    var p = parser.Parser{ .s = s, .i = 0, .opts = opts };
+    return p.parse(alloc);
+}
+
+// matchFirst call m.match with the first node that matches the selector s, from the
+// descendants of n and returns true. If none matches, it returns false.
+pub fn matchFirst(s: Selector, node: anytype, m: anytype) !bool {
+    var c = try node.firstChild();
+    while (true) {
+        if (c == null) break;
+
+        if (try s.match(c.?)) {
+            try m.match(c.?);
+            return true;
+        }
+
+        if (try matchFirst(s, c.?, m)) return true;
+        c = try c.?.nextSibling();
+    }
+    return false;
+}
+
+// matchAll call m.match with the all the nodes that matches the selector s, from the
+// descendants of n.
+pub fn matchAll(s: Selector, node: anytype, m: anytype) !void {
+    var c = try node.firstChild();
+    while (true) {
+        if (c == null) break;
+
+        if (try s.match(c.?)) try m.match(c.?);
+        try matchAll(s, c.?, m);
+        c = try c.?.nextSibling();
+    }
+}
+
+test "parse" {
+    const alloc = std.testing.allocator;
+
+    const testcases = [_][]const u8{
+        "address",
+        "*",
+        "#foo",
+        "li#t1",
+        "*#t4",
+        ".t1",
+        "p.t1",
+        "div.teST",
+        ".t1.fail",
+        "p.t1.t2",
+        "p.--t1",
+        "p.--t1.--t2",
+        "p[title]",
+        "div[class=\"red\" i]",
+        "address[title=\"foo\"]",
+        "address[title=\"FoOIgnoRECaSe\" i]",
+        "address[title!=\"foo\"]",
+        "address[title!=\"foo\" i]",
+        "p[title!=\"FooBarUFoo\" i]",
+        "[  \t title        ~=       foo    ]",
+        "p[title~=\"FOO\" i]",
+        "p[title~=toofoo i]",
+        "[title~=\"hello world\"]",
+        "[title~=\"hello\" i]",
+        "[title~=\"hello\"          I]",
+        "[lang|=\"en\"]",
+        "[lang|=\"EN\" i]",
+        "[lang|=\"EN\"     i]",
+        "[title^=\"foo\"]",
+        "[title^=\"foo\" i]",
+        "[title$=\"bar\"]",
+        "[title$=\"BAR\" i]",
+        "[title*=\"bar\"]",
+        "[title*=\"BaRu\" i]",
+        "[title*=\"BaRu\" I]",
+        "p[class$=\" \"]",
+        "p[class$=\"\"]",
+        "p[class^=\" \"]",
+        "p[class^=\"\"]",
+        "p[class*=\" \"]",
+        "p[class*=\"\"]",
+        "input[name=Sex][value=F]",
+        "table[border=\"0\"][cellpadding=\"0\"][cellspacing=\"0\"]",
+        ".t1:not(.t2)",
+        "div:not(.t1)",
+        "div:not([class=\"t2\"])",
+        "li:nth-child(odd)",
+        "li:nth-child(even)",
+        "li:nth-child(-n+2)",
+        "li:nth-child(3n+1)",
+        "li:nth-last-child(odd)",
+        "li:nth-last-child(even)",
+        "li:nth-last-child(-n+2)",
+        "li:nth-last-child(3n+1)",
+        "span:first-child",
+        "span:last-child",
+        "p:nth-of-type(2)",
+        "p:nth-last-of-type(2)",
+        "p:last-of-type",
+        "p:first-of-type",
+        "p:only-child",
+        "p:only-of-type",
+        ":empty",
+        "div p",
+        "div table p",
+        "div > p",
+        "p ~ p",
+        "p + p",
+        "li, p",
+        "p +/*This is a comment*/ p",
+        "p:contains(\"that wraps\")",
+        "p:containsOwn(\"that wraps\")",
+        ":containsOwn(\"inner\")",
+        "p:containsOwn(\"block\")",
+        "div:has(#p1)",
+        "div:has(:containsOwn(\"2\"))",
+        "body :has(:containsOwn(\"2\"))",
+        "body :haschild(:containsOwn(\"2\"))",
+        "p:matches([\\d])",
+        "p:matches([a-z])",
+        "p:matches([a-zA-Z])",
+        "p:matches([^\\d])",
+        "p:matches(^(0|a))",
+        "p:matches(^\\d+$)",
+        "p:not(:matches(^\\d+$))",
+        "div :matchesOwn(^\\d+$)",
+        "[href#=(fina)]:not([href#=(\\/\\/[^\\/]+untrusted)])",
+        "[href#=(^https:\\/\\/[^\\/]*\\/?news)]",
+        ":input",
+        ":root",
+        "*:root",
+        "html:nth-child(1)",
+        "*:root:first-child",
+        "*:root:nth-child(1)",
+        "a:not(:root)",
+        "body > *:nth-child(3n+2)",
+        "input:disabled",
+        ":disabled",
+        ":enabled",
+        "div.class1, div.class2",
+    };
+
+    for (testcases) |tc| {
+        const s = parse(alloc, tc, .{}) catch |e| {
+            std.debug.print("query {s}", .{tc});
+            return e;
+        };
+        defer s.deinit(alloc);
+    }
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.CSS" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "CSS.supports('display: flex')", "true" },
+        .{ "CSS.supports('text-decoration-style', 'blink')", "true" },
+    }, .{});
+}
--- a/src/browser/css/libdom.zig
+++ b/src/browser/css/libdom.zig
@@ -0,0 +1,102 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+
+// Node implementation with Netsurf Libdom C lib.
+pub const Node = struct {
+    node: *parser.Node,
+
+    pub fn firstChild(n: Node) !?Node {
+        const c = try parser.nodeFirstChild(n.node);
+        if (c) |cc| return .{ .node = cc };
+
+        return null;
+    }
+
+    pub fn lastChild(n: Node) !?Node {
+        const c = try parser.nodeLastChild(n.node);
+        if (c) |cc| return .{ .node = cc };
+
+        return null;
+    }
+
+    pub fn nextSibling(n: Node) !?Node {
+        const c = try parser.nodeNextSibling(n.node);
+        if (c) |cc| return .{ .node = cc };
+
+        return null;
+    }
+
+    pub fn prevSibling(n: Node) !?Node {
+        const c = try parser.nodePreviousSibling(n.node);
+        if (c) |cc| return .{ .node = cc };
+
+        return null;
+    }
+
+    pub fn parent(n: Node) !?Node {
+        const c = try parser.nodeParentNode(n.node);
+        if (c) |cc| return .{ .node = cc };
+
+        return null;
+    }
+
+    pub fn isElement(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .element;
+    }
+
+    pub fn isDocument(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .document;
+    }
+
+    pub fn isComment(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .comment;
+    }
+
+    pub fn isText(n: Node) bool {
+        const t = parser.nodeType(n.node) catch return false;
+        return t == .text;
+    }
+
+    pub fn isEmptyText(n: Node) !bool {
+        const data = try parser.nodeTextContent(n.node);
+        if (data == null) return true;
+        if (data.?.len == 0) return true;
+
+        return std.mem.trim(u8, data.?, &std.ascii.whitespace).len == 0;
+    }
+
+    pub fn tag(n: Node) ![]const u8 {
+        return try parser.nodeName(n.node);
+    }
+
+    pub fn attr(n: Node, key: []const u8) !?[]const u8 {
+        if (!n.isElement()) return null;
+        return try parser.elementGetAttribute(parser.nodeToElement(n.node), key);
+    }
+
+    pub fn eql(a: Node, b: Node) bool {
+        return a.node == b.node;
+    }
+};
--- a/src/browser/css/libdom_test.zig
+++ b/src/browser/css/libdom_test.zig
@@ -0,0 +1,325 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const css = @import("css.zig");
+const Node = @import("libdom.zig").Node;
+const parser = @import("../netsurf.zig");
+
+const Matcher = struct {
+    const Nodes = std.ArrayList(Node);
+
+    nodes: Nodes,
+
+    fn init(alloc: std.mem.Allocator) Matcher {
+        return .{ .nodes = Nodes.init(alloc) };
+    }
+
+    fn deinit(m: *Matcher) void {
+        m.nodes.deinit();
+    }
+
+    fn reset(m: *Matcher) void {
+        m.nodes.clearRetainingCapacity();
+    }
+
+    pub fn match(m: *Matcher, n: Node) !void {
+        try m.nodes.append(n);
+    }
+};
+
+test "matchFirst" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    const testcases = [_]struct {
+        q: []const u8,
+        html: []const u8,
+        exp: usize,
+    }{
+        .{ .q = "address", .html = "<body><address>This address...</address></body>", .exp = 1 },
+        .{ .q = "*", .html = "<!-- comment --><html><head></head><body>text</body></html>", .exp = 1 },
+        .{ .q = "*", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "#foo", .html = "<p id=\"foo\"><p id=\"bar\">", .exp = 1 },
+        .{ .q = "li#t1", .html = "<ul><li id=\"t1\"><p id=\"t1\">", .exp = 1 },
+        .{ .q = ".t3", .html = "<ul><li class=\"t1\"><li class=\"t2 t3\">", .exp = 1 },
+        .{ .q = "*#t4", .html = "<ol><li id=\"t4\"><li id=\"t44\">", .exp = 1 },
+        .{ .q = ".t1", .html = "<ul><li class=\"t1\"><li class=\"t2\">", .exp = 1 },
+        .{ .q = "p.t1", .html = "<p class=\"t1 t2\">", .exp = 1 },
+        .{ .q = "div.teST", .html = "<div class=\"test\">", .exp = 0 },
+        .{ .q = ".t1.fail", .html = "<p class=\"t1 t2\">", .exp = 0 },
+        .{ .q = "p.t1.t2", .html = "<p class=\"t1 t2\">", .exp = 1 },
+        .{ .q = "p.--t1", .html = "<p class=\"--t1 --t2\">", .exp = 1 },
+        .{ .q = "p.--t1.--t2", .html = "<p class=\"--t1 --t2\">", .exp = 1 },
+        .{ .q = "p[title]", .html = "<p><p title=\"title\">", .exp = 1 },
+        .{ .q = "div[class=\"red\" i]", .html = "<div><div class=\"Red\">", .exp = 1 },
+        .{ .q = "address[title=\"foo\"]", .html = "<address><address title=\"foo\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "address[title=\"FoOIgnoRECaSe\" i]", .html = "<address><address title=\"fooIgnoreCase\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "address[title!=\"foo\"]", .html = "<address><address title=\"foo\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "address[title!=\"foo\" i]", .html = "<address><address title=\"FOO\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "p[title!=\"FooBarUFoo\" i]", .html = "<p title=\"fooBARuFOO\"><p title=\"varfoo\">", .exp = 1 },
+        .{ .q = "[   title        ~=       foo    ]", .html = "<p title=\"tot foo bar\">", .exp = 1 },
+        .{ .q = "p[title~=\"FOO\" i]", .html = "<p title=\"tot foo bar\">", .exp = 1 },
+        .{ .q = "p[title~=toofoo i]", .html = "<p title=\"tot foo bar\">", .exp = 0 },
+        .{ .q = "[title~=\"hello world\"]", .html = "<p title=\"hello world\">", .exp = 0 },
+        .{ .q = "[title~=\"hello\" i]", .html = "<p title=\"HELLO world\">", .exp = 1 },
+        .{ .q = "[title~=\"hello\"          I]", .html = "<p title=\"HELLO world\">", .exp = 1 },
+        .{ .q = "[lang|=\"en\"]", .html = "<p lang=\"en\"><p lang=\"en-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 1 },
+        .{ .q = "[lang|=\"EN\" i]", .html = "<p lang=\"en\"><p lang=\"En-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 1 },
+        .{ .q = "[lang|=\"EN\"     i]", .html = "<p lang=\"en\"><p lang=\"En-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 1 },
+        .{ .q = "[title^=\"foo\"]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title^=\"foo\" i]", .html = "<p title=\"FooBAR\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title$=\"bar\"]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title$=\"BAR\" i]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title*=\"bar\"]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "[title*=\"BaRu\" i]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "[title*=\"BaRu\" I]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "p[class$=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class$=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class^=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class^=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class*=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class*=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "input[name=Sex][value=F]", .html = "<input type=\"radio\" name=\"Sex\" value=\"F\"/>", .exp = 1 },
+        .{ .q = "table[border=\"0\"][cellpadding=\"0\"][cellspacing=\"0\"]", .html = "<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" style=\"table-layout: fixed; width: 100%; border: 0 dashed; border-color: #FFFFFF\"><tr style=\"height:64px\">aaa</tr></table>", .exp = 1 },
+        .{ .q = ".t1:not(.t2)", .html = "<p class=\"t1 t2\">", .exp = 0 },
+        .{ .q = "div:not(.t1)", .html = "<div class=\"t3\">", .exp = 1 },
+        .{ .q = "div:not([class=\"t2\"])", .html = "<div><div class=\"t2\"><div class=\"t3\">", .exp = 1 },
+        .{ .q = "li:nth-child(odd)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-child(even)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-child(-n+2)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-child(3n+1)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-last-child(odd)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 1 },
+        .{ .q = "li:nth-last-child(even)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 1 },
+        .{ .q = "li:nth-last-child(-n+2)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 1 },
+        .{ .q = "li:nth-last-child(3n+1)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 1 },
+        .{ .q = "span:first-child", .html = "<p>some text <span id=\"1\">and a span</span><span id=\"2\"> and another</span></p>", .exp = 1 },
+        .{ .q = "span:last-child", .html = "<span>a span</span> and some text", .exp = 1 },
+        .{ .q = "p:nth-of-type(2)", .html = "<address></address><p id=1><p id=2>", .exp = 1 },
+        .{ .q = "p:nth-last-of-type(2)", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:last-of-type", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:first-of-type", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:only-child", .html = "<div><p id=\"1\"></p><a></a></div><div><p id=\"2\"></p></div>", .exp = 1 },
+        .{ .q = "p:only-of-type", .html = "<div><p id=\"1\"></p><a></a></div><div><p id=\"2\"></p><p id=\"3\"></p></div>", .exp = 1 },
+        .{ .q = ":empty", .html = "<p id=\"1\"><!-- --><p id=\"2\">Hello<p id=\"3\"><span>", .exp = 1 },
+        .{ .q = "div p", .html = "<div><p id=\"1\"><table><tr><td><p id=\"2\"></table></div><p id=\"3\">", .exp = 1 },
+        .{ .q = "div table p", .html = "<div><p id=\"1\"><table><tr><td><p id=\"2\"></table></div><p id=\"3\">", .exp = 1 },
+        .{ .q = "div > p", .html = "<div><p id=\"1\"><div><p id=\"2\"></div><table><tr><td><p id=\"3\"></table></div>", .exp = 1 },
+        .{ .q = "p ~ p", .html = "<p id=\"1\"><p id=\"2\"></p><address></address><p id=\"3\">", .exp = 1 },
+        .{ .q = "p + p", .html = "<p id=\"1\"></p> <!--comment--> <p id=\"2\"></p><address></address><p id=\"3\">", .exp = 1 },
+        .{ .q = "li, p", .html = "<ul><li></li><li></li></ul><p>", .exp = 1 },
+        .{ .q = "p +/*This is a comment*/ p", .html = "<p id=\"1\"><p id=\"2\"></p><address></address><p id=\"3\">", .exp = 1 },
+        // .{ .q = "p:contains(\"that wraps\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        // .{ .q = "p:containsOwn(\"that wraps\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 0 },
+        // .{ .q = ":containsOwn(\"inner\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        // .{ .q = "p:containsOwn(\"block\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        // .{ .q = "div:has(#p1)", .html = "<div id=\"d1\"><p id=\"p1\"><span>text content</span></p></div><div id=\"d2\"/>", .exp = 1 },
+        // .{ .q = "div:has(:containsOwn(\"2\"))", .html = "<div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p>contents <em>2</em></p></div>", .exp = 1 },
+        // .{ .q = "body :has(:containsOwn(\"2\"))", .html = "<body><div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p id=\"p2\">contents <em>2</em></p></div></body>", .exp = 1 },
+        // .{ .q = "body :haschild(:containsOwn(\"2\"))", .html = "<body><div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p id=\"p2\">contents <em>2</em></p></div></body>", .exp = 1 },
+        // .{ .q = "p:matches([\\d])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches([a-z])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches([a-zA-Z])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches([^\\d])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches(^(0|a))", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches(^\\d+$)", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:not(:matches(^\\d+$))", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "div :matchesOwn(^\\d+$)", .html = "<div><p id=\"p1\">01234<em>567</em>89</p><div>", .exp = 1 },
+        // .{ .q = "[href#=(fina)]:not([href#=(\\/\\/[^\\/]+untrusted)])", .html = "<ul> <li><a id=\"a1\" href=\"http://www.google.com/finance\"></a> <li><a id=\"a2\" href=\"http://finance.yahoo.com/\"></a> <li><a id=\"a2\" href=\"http://finance.untrusted.com/\"/> <li><a id=\"a3\" href=\"https://www.google.com/news\"/> <li><a id=\"a4\" href=\"http://news.yahoo.com\"/> </ul>", .exp = 1 },
+        // .{ .q = "[href#=(^https:\\/\\/[^\\/]*\\/?news)]", .html = "<ul> <li><a id=\"a1\" href=\"http://www.google.com/finance\"/> <li><a id=\"a2\" href=\"http://finance.yahoo.com/\"/> <li><a id=\"a3\" href=\"https://www.google.com/news\"></a> <li><a id=\"a4\" href=\"http://news.yahoo.com\"/> </ul>", .exp = 1 },
+        .{ .q = ":input", .html = "<form> <label>Username <input type=\"text\" name=\"username\" /></label> <label>Password <input type=\"password\" name=\"password\" /></label> <label>Country <select name=\"country\"> <option value=\"ca\">Canada</option> <option value=\"us\">United States</option> </select> </label> <label>Bio <textarea name=\"bio\"></textarea></label> <button>Sign up</button> </form>", .exp = 1 },
+        .{ .q = ":root", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "html:nth-child(1)", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root:first-child", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root:nth-child(1)", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "a:not(:root)", .html = "<html><head></head><body><a href=\"http://www.foo.com\"></a></body></html>", .exp = 1 },
+        .{ .q = "body > *:nth-child(3n+2)", .html = "<html><head></head><body><p></p><div></div><span></span><a></a><form></form></body></html>", .exp = 1 },
+        .{ .q = "input:disabled", .html = "<html><head></head><body><fieldset disabled><legend id=\"1\"><input id=\"i1\"/></legend><legend id=\"2\"><input id=\"i2\"/></legend></fieldset></body></html>", .exp = 1 },
+        .{ .q = ":disabled", .html = "<html><head></head><body><fieldset disabled></fieldset></body></html>", .exp = 1 },
+        .{ .q = ":enabled", .html = "<html><head></head><body><fieldset></fieldset></body></html>", .exp = 1 },
+        .{ .q = "div.class1, div.class2", .html = "<div class=class1></div><div class=class2></div><div class=class3></div>", .exp = 1 },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const doc = try parser.documentHTMLParseFromStr(tc.html);
+        defer parser.documentHTMLClose(doc) catch {};
+
+        const s = css.parse(alloc, tc.q, .{}) catch |e| {
+            std.debug.print("parse, query: {s}\n", .{tc.q});
+            return e;
+        };
+
+        defer s.deinit(alloc);
+
+        const node = Node{ .node = parser.documentHTMLToNode(doc) };
+
+        _ = css.matchFirst(s, node, &matcher) catch |e| {
+            std.debug.print("match, query: {s}\n", .{tc.q});
+            return e;
+        };
+        std.testing.expectEqual(tc.exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("expectation, query: {s}\n", .{tc.q});
+            return e;
+        };
+    }
+}
+
+test "matchAll" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    const testcases = [_]struct {
+        q: []const u8,
+        html: []const u8,
+        exp: usize,
+    }{
+        .{ .q = "address", .html = "<body><address>This address...</address></body>", .exp = 1 },
+        .{ .q = "*", .html = "<!-- comment --><html><head></head><body>text</body></html>", .exp = 3 },
+        .{ .q = "*", .html = "<html><head></head><body></body></html>", .exp = 3 },
+        .{ .q = "#foo", .html = "<p id=\"foo\"><p id=\"bar\">", .exp = 1 },
+        .{ .q = "li#t1", .html = "<ul><li id=\"t1\"><p id=\"t1\">", .exp = 1 },
+        .{ .q = ".t3", .html = "<ul><li class=\"t1\"><li class=\"t2 t3\">", .exp = 1 },
+        .{ .q = "*#t4", .html = "<ol><li id=\"t4\"><li id=\"t44\">", .exp = 1 },
+        .{ .q = ".t1", .html = "<ul><li class=\"t1\"><li class=\"t2\">", .exp = 1 },
+        .{ .q = "p.t1", .html = "<p class=\"t1 t2\">", .exp = 1 },
+        .{ .q = "div.teST", .html = "<div class=\"test\">", .exp = 0 },
+        .{ .q = ".t1.fail", .html = "<p class=\"t1 t2\">", .exp = 0 },
+        .{ .q = "p.t1.t2", .html = "<p class=\"t1 t2\">", .exp = 1 },
+        .{ .q = "p.--t1", .html = "<p class=\"--t1 --t2\">", .exp = 1 },
+        .{ .q = "p.--t1.--t2", .html = "<p class=\"--t1 --t2\">", .exp = 1 },
+        .{ .q = "p[title]", .html = "<p><p title=\"title\">", .exp = 1 },
+        .{ .q = "div[class=\"red\" i]", .html = "<div><div class=\"Red\">", .exp = 1 },
+        .{ .q = "address[title=\"foo\"]", .html = "<address><address title=\"foo\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "address[title=\"FoOIgnoRECaSe\" i]", .html = "<address><address title=\"fooIgnoreCase\"><address title=\"bar\">", .exp = 1 },
+        .{ .q = "address[title!=\"foo\"]", .html = "<address><address title=\"foo\"><address title=\"bar\">", .exp = 2 },
+        .{ .q = "address[title!=\"foo\" i]", .html = "<address><address title=\"FOO\"><address title=\"bar\">", .exp = 2 },
+        .{ .q = "p[title!=\"FooBarUFoo\" i]", .html = "<p title=\"fooBARuFOO\"><p title=\"varfoo\">", .exp = 1 },
+        .{ .q = "[   title        ~=       foo    ]", .html = "<p title=\"tot foo bar\">", .exp = 1 },
+        .{ .q = "p[title~=\"FOO\" i]", .html = "<p title=\"tot foo bar\">", .exp = 1 },
+        .{ .q = "p[title~=toofoo i]", .html = "<p title=\"tot foo bar\">", .exp = 0 },
+        .{ .q = "[title~=\"hello world\"]", .html = "<p title=\"hello world\">", .exp = 0 },
+        .{ .q = "[title~=\"hello\" i]", .html = "<p title=\"HELLO world\">", .exp = 1 },
+        .{ .q = "[title~=\"hello\"          I]", .html = "<p title=\"HELLO world\">", .exp = 1 },
+        .{ .q = "[lang|=\"en\"]", .html = "<p lang=\"en\"><p lang=\"en-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 2 },
+        .{ .q = "[lang|=\"EN\" i]", .html = "<p lang=\"en\"><p lang=\"En-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 2 },
+        .{ .q = "[lang|=\"EN\"     i]", .html = "<p lang=\"en\"><p lang=\"En-gb\"><p lang=\"enough\"><p lang=\"fr-en\">", .exp = 2 },
+        .{ .q = "[title^=\"foo\"]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title^=\"foo\" i]", .html = "<p title=\"FooBAR\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title$=\"bar\"]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title$=\"BAR\" i]", .html = "<p title=\"foobar\"><p title=\"barfoo\">", .exp = 1 },
+        .{ .q = "[title*=\"bar\"]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "[title*=\"BaRu\" i]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "[title*=\"BaRu\" I]", .html = "<p title=\"foobarufoo\">", .exp = 1 },
+        .{ .q = "p[class$=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class$=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class^=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class^=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class*=\" \"]", .html = "<p class=\" \">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "p[class*=\"\"]", .html = "<p class=\"\">This text should be green.</p><p>This text should be green.</p>", .exp = 0 },
+        .{ .q = "input[name=Sex][value=F]", .html = "<input type=\"radio\" name=\"Sex\" value=\"F\"/>", .exp = 1 },
+        .{ .q = "table[border=\"0\"][cellpadding=\"0\"][cellspacing=\"0\"]", .html = "<table border=\"0\" cellpadding=\"0\" cellspacing=\"0\" style=\"table-layout: fixed; width: 100%; border: 0 dashed; border-color: #FFFFFF\"><tr style=\"height:64px\">aaa</tr></table>", .exp = 1 },
+        .{ .q = ".t1:not(.t2)", .html = "<p class=\"t1 t2\">", .exp = 0 },
+        .{ .q = "div:not(.t1)", .html = "<div class=\"t3\">", .exp = 1 },
+        .{ .q = "div:not([class=\"t2\"])", .html = "<div><div class=\"t2\"><div class=\"t3\">", .exp = 2 },
+        .{ .q = "li:nth-child(odd)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 2 },
+        .{ .q = "li:nth-child(even)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-child(-n+2)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 2 },
+        .{ .q = "li:nth-child(3n+1)", .html = "<ol><li id=1><li id=2><li id=3></ol>", .exp = 1 },
+        .{ .q = "li:nth-last-child(odd)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 2 },
+        .{ .q = "li:nth-last-child(even)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 2 },
+        .{ .q = "li:nth-last-child(-n+2)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 2 },
+        .{ .q = "li:nth-last-child(3n+1)", .html = "<ol><li id=1><li id=2><li id=3><li id=4></ol>", .exp = 2 },
+        .{ .q = "span:first-child", .html = "<p>some text <span id=\"1\">and a span</span><span id=\"2\"> and another</span></p>", .exp = 1 },
+        .{ .q = "span:last-child", .html = "<span>a span</span> and some text", .exp = 1 },
+        .{ .q = "p:nth-of-type(2)", .html = "<address></address><p id=1><p id=2>", .exp = 1 },
+        .{ .q = "p:nth-last-of-type(2)", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:last-of-type", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:first-of-type", .html = "<address></address><p id=1><p id=2></p><a>", .exp = 1 },
+        .{ .q = "p:only-child", .html = "<div><p id=\"1\"></p><a></a></div><div><p id=\"2\"></p></div>", .exp = 1 },
+        .{ .q = "p:only-of-type", .html = "<div><p id=\"1\"></p><a></a></div><div><p id=\"2\"></p><p id=\"3\"></p></div>", .exp = 1 },
+        .{ .q = ":empty", .html = "<p id=\"1\"><!-- --><p id=\"2\">Hello<p id=\"3\"><span>", .exp = 3 },
+        .{ .q = "div p", .html = "<div><p id=\"1\"><table><tr><td><p id=\"2\"></table></div><p id=\"3\">", .exp = 2 },
+        .{ .q = "div table p", .html = "<div><p id=\"1\"><table><tr><td><p id=\"2\"></table></div><p id=\"3\">", .exp = 1 },
+        .{ .q = "div > p", .html = "<div><p id=\"1\"><div><p id=\"2\"></div><table><tr><td><p id=\"3\"></table></div>", .exp = 2 },
+        .{ .q = "p ~ p", .html = "<p id=\"1\"><p id=\"2\"></p><address></address><p id=\"3\">", .exp = 2 },
+        .{ .q = "p + p", .html = "<p id=\"1\"></p> <!--comment--> <p id=\"2\"></p><address></address><p id=\"3\">", .exp = 1 },
+        .{ .q = "li, p", .html = "<ul><li></li><li></li></ul><p>", .exp = 3 },
+        .{ .q = "p +/*This is a comment*/ p", .html = "<p id=\"1\"><p id=\"2\"></p><address></address><p id=\"3\">", .exp = 1 },
+        // .{ .q = "p:contains(\"that wraps\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        // .{ .q = "p:containsOwn(\"that wraps\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 0 },
+        // .{ .q = ":containsOwn(\"inner\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        // .{ .q = "p:containsOwn(\"block\")", .html = "<p>Text block that <span>wraps inner text</span> and continues</p>", .exp = 1 },
+        .{ .q = "div:has(#p1)", .html = "<div id=\"d1\"><p id=\"p1\"><span>text content</span></p></div><div id=\"d2\"/>", .exp = 1 },
+        // .{ .q = "div:has(:containsOwn(\"2\"))", .html = "<div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p>contents <em>2</em></p></div>", .exp = 1 },
+        // .{ .q = "body :has(:containsOwn(\"2\"))", .html = "<body><div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p id=\"p2\">contents <em>2</em></p></div></body>", .exp = 2 },
+        // .{ .q = "body :haschild(:containsOwn(\"2\"))", .html = "<body><div id=\"d1\"><p id=\"p1\"><span>contents 1</span></p></div> <div id=\"d2\"><p id=\"p2\">contents <em>2</em></p></div></body>", .exp = 1 },
+        // .{ .q = "p:matches([\\d])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 2 },
+        // .{ .q = "p:matches([a-z])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:matches([a-zA-Z])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 2 },
+        // .{ .q = "p:matches([^\\d])", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 2 },
+        // .{ .q = "p:matches(^(0|a))", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 3 },
+        // .{ .q = "p:matches(^\\d+$)", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 1 },
+        // .{ .q = "p:not(:matches(^\\d+$))", .html = "<p id=\"p1\">0123456789</p><p id=\"p2\">abcdef</p><p id=\"p3\">0123ABCD</p>", .exp = 2 },
+        // .{ .q = "div :matchesOwn(^\\d+$)", .html = "<div><p id=\"p1\">01234<em>567</em>89</p><div>", .exp = 2 },
+        // .{ .q = "[href#=(fina)]:not([href#=(\\/\\/[^\\/]+untrusted)])", .html = "<ul> <li><a id=\"a1\" href=\"http://www.google.com/finance\"></a> <li><a id=\"a2\" href=\"http://finance.yahoo.com/\"></a> <li><a id=\"a2\" href=\"http://finance.untrusted.com/\"/> <li><a id=\"a3\" href=\"https://www.google.com/news\"/> <li><a id=\"a4\" href=\"http://news.yahoo.com\"/> </ul>", .exp = 2 },
+        // .{ .q = "[href#=(^https:\\/\\/[^\\/]*\\/?news)]", .html = "<ul> <li><a id=\"a1\" href=\"http://www.google.com/finance\"/> <li><a id=\"a2\" href=\"http://finance.yahoo.com/\"/> <li><a id=\"a3\" href=\"https://www.google.com/news\"></a> <li><a id=\"a4\" href=\"http://news.yahoo.com\"/> </ul>", .exp = 1 },
+        .{ .q = ":input", .html = "<form> <label>Username <input type=\"text\" name=\"username\" /></label> <label>Password <input type=\"password\" name=\"password\" /></label> <label>Country <select name=\"country\"> <option value=\"ca\">Canada</option> <option value=\"us\">United States</option> </select> </label> <label>Bio <textarea name=\"bio\"></textarea></label> <button>Sign up</button> </form>", .exp = 5 },
+        .{ .q = ":root", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "html:nth-child(1)", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root:first-child", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "*:root:nth-child(1)", .html = "<html><head></head><body></body></html>", .exp = 1 },
+        .{ .q = "a:not(:root)", .html = "<html><head></head><body><a href=\"http://www.foo.com\"></a></body></html>", .exp = 1 },
+        .{ .q = "body > *:nth-child(3n+2)", .html = "<html><head></head><body><p></p><div></div><span></span><a></a><form></form></body></html>", .exp = 2 },
+        .{ .q = "input:disabled", .html = "<html><head></head><body><fieldset disabled><legend id=\"1\"><input id=\"i1\"/></legend><legend id=\"2\"><input id=\"i2\"/></legend></fieldset></body></html>", .exp = 1 },
+        .{ .q = ":disabled", .html = "<html><head></head><body><fieldset disabled></fieldset></body></html>", .exp = 1 },
+        .{ .q = ":enabled", .html = "<html><head></head><body><fieldset></fieldset></body></html>", .exp = 1 },
+        .{ .q = "div.class1, div.class2", .html = "<div class=class1></div><div class=class2></div><div class=class3></div>", .exp = 2 },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const doc = try parser.documentHTMLParseFromStr(tc.html);
+        defer parser.documentHTMLClose(doc) catch {};
+
+        const s = css.parse(alloc, tc.q, .{}) catch |e| {
+            std.debug.print("parse, query: {s}\n", .{tc.q});
+            return e;
+        };
+        defer s.deinit(alloc);
+
+        const node = Node{ .node = parser.documentHTMLToNode(doc) };
+
+        _ = css.matchAll(s, node, &matcher) catch |e| {
+            std.debug.print("match, query: {s}\n", .{tc.q});
+            return e;
+        };
+        std.testing.expectEqual(tc.exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("expectation, query: {s}\n", .{tc.q});
+            return e;
+        };
+    }
+}
--- a/src/browser/css/match_test.zig
+++ b/src/browser/css/match_test.zig
@@ -0,0 +1,587 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const css = @import("css.zig");
+
+// Node mock implementation for test only.
+pub const Node = struct {
+    child: ?*const Node = null,
+    last: ?*const Node = null,
+    sibling: ?*const Node = null,
+    prev: ?*const Node = null,
+    par: ?*const Node = null,
+
+    name: []const u8 = "",
+    att: ?[]const u8 = null,
+
+    pub fn firstChild(n: *const Node) !?*const Node {
+        return n.child;
+    }
+
+    pub fn lastChild(n: *const Node) !?*const Node {
+        return n.last;
+    }
+
+    pub fn nextSibling(n: *const Node) !?*const Node {
+        return n.sibling;
+    }
+
+    pub fn prevSibling(n: *const Node) !?*const Node {
+        return n.prev;
+    }
+
+    pub fn parent(n: *const Node) !?*const Node {
+        return n.par;
+    }
+
+    pub fn isElement(_: *const Node) bool {
+        return true;
+    }
+
+    pub fn isDocument(_: *const Node) bool {
+        return false;
+    }
+
+    pub fn isComment(_: *const Node) bool {
+        return false;
+    }
+
+    pub fn isText(_: *const Node) bool {
+        return false;
+    }
+
+    pub fn isEmptyText(_: *const Node) !bool {
+        return false;
+    }
+
+    pub fn tag(n: *const Node) ![]const u8 {
+        return n.name;
+    }
+
+    pub fn attr(n: *const Node, _: []const u8) !?[]const u8 {
+        return n.att;
+    }
+
+    pub fn eql(a: *const Node, b: *const Node) bool {
+        return a == b;
+    }
+};
+
+const Matcher = struct {
+    const Nodes = std.ArrayList(*const Node);
+
+    nodes: Nodes,
+
+    fn init(alloc: std.mem.Allocator) Matcher {
+        return .{ .nodes = Nodes.init(alloc) };
+    }
+
+    fn deinit(m: *Matcher) void {
+        m.nodes.deinit();
+    }
+
+    fn reset(m: *Matcher) void {
+        m.nodes.clearRetainingCapacity();
+    }
+
+    pub fn match(m: *Matcher, n: *const Node) !void {
+        try m.nodes.append(n);
+    }
+};
+
+test "matchFirst" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    const testcases = [_]struct {
+        q: []const u8,
+        n: Node,
+        exp: usize,
+    }{
+        .{
+            .q = "address",
+            .n = .{ .child = &.{ .name = "body", .child = &.{ .name = "address" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "#foo",
+            .n = .{ .child = &.{ .name = "p", .att = "foo", .child = &.{ .name = "p" } } },
+            .exp = 1,
+        },
+        .{
+            .q = ".t1",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "t1" } } },
+            .exp = 1,
+        },
+        .{
+            .q = ".t1",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "foo t1" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo!=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo!=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo~=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "baz bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo~=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo^=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo$=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo*=rb]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar-baz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "ba" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "strong, a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a", .par = &.{ .name = "p" } }, .sibling = &.{ .name = "a" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "span", .child = &.{
+                .name = "a",
+                .par = &.{ .name = "span", .par = &.{ .name = "p" } },
+            } } } },
+            .exp = 1,
+        },
+        .{
+            .q = ":not(p)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p:has(a)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p:has(strong)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "p:haschild(a)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p:haschild(strong)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "p:lang(en)",
+            .n = .{ .child = &.{ .name = "p", .att = "en-US", .child = &.{ .name = "a" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "a:lang(en)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a", .par = &.{ .att = "en-US" } } } },
+            .exp = 1,
+        },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const s = try css.parse(alloc, tc.q, .{});
+        defer s.deinit(alloc);
+
+        _ = css.matchFirst(s, &tc.n, &matcher) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+
+        std.testing.expectEqual(tc.exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+    }
+}
+
+test "matchAll" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    const testcases = [_]struct {
+        q: []const u8,
+        n: Node,
+        exp: usize,
+    }{
+        .{
+            .q = "address",
+            .n = .{ .child = &.{ .name = "body", .child = &.{ .name = "address" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "#foo",
+            .n = .{ .child = &.{ .name = "p", .att = "foo", .child = &.{ .name = "p" } } },
+            .exp = 1,
+        },
+        .{
+            .q = ".t1",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "t1" } } },
+            .exp = 1,
+        },
+        .{
+            .q = ".t1",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "foo t1" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo!=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo!=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 2,
+        },
+        .{
+            .q = "[foo~=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "baz bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo~=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "[foo^=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo$=baz]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo*=rb]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "barbaz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "bar-baz" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "[foo|=bar]",
+            .n = .{ .child = &.{ .name = "p", .sibling = &.{ .name = "p", .att = "ba" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "strong, a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 2,
+        },
+        .{
+            .q = "p a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a", .par = &.{ .name = "p" } }, .sibling = &.{ .name = "a" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p a",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "span", .child = &.{
+                .name = "a",
+                .par = &.{ .name = "span", .par = &.{ .name = "p" } },
+            } } } },
+            .exp = 1,
+        },
+        .{
+            .q = ":not(p)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 2,
+        },
+        .{
+            .q = "p:has(a)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p:has(strong)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "p:haschild(a)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "p:haschild(strong)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a" }, .sibling = &.{ .name = "strong" } } },
+            .exp = 0,
+        },
+        .{
+            .q = "p:lang(en)",
+            .n = .{ .child = &.{ .name = "p", .att = "en-US", .child = &.{ .name = "a" } } },
+            .exp = 1,
+        },
+        .{
+            .q = "a:lang(en)",
+            .n = .{ .child = &.{ .name = "p", .child = &.{ .name = "a", .par = &.{ .att = "en-US" } } } },
+            .exp = 1,
+        },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const s = try css.parse(alloc, tc.q, .{});
+        defer s.deinit(alloc);
+
+        css.matchAll(s, &tc.n, &matcher) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+
+        std.testing.expectEqual(tc.exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+    }
+}
+
+test "pseudo class" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    var p1: Node = .{ .name = "p" };
+    var p2: Node = .{ .name = "p" };
+    var a1: Node = .{ .name = "a" };
+
+    p1.sibling = &p2;
+    p2.prev = &p1;
+
+    p2.sibling = &a1;
+    a1.prev = &p2;
+
+    var root: Node = .{ .child = &p1, .last = &a1 };
+    p1.par = &root;
+    p2.par = &root;
+    a1.par = &root;
+
+    const testcases = [_]struct {
+        q: []const u8,
+        n: Node,
+        exp: ?*const Node,
+    }{
+        .{ .q = "p:only-child", .n = root, .exp = null },
+        .{ .q = "a:only-of-type", .n = root, .exp = &a1 },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const s = try css.parse(alloc, tc.q, .{});
+        defer s.deinit(alloc);
+
+        css.matchAll(s, &tc.n, &matcher) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+
+        if (tc.exp) |exp_n| {
+            const exp: usize = 1;
+            std.testing.expectEqual(exp, matcher.nodes.items.len) catch |e| {
+                std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+                return e;
+            };
+
+            std.testing.expectEqual(exp_n, matcher.nodes.items[0]) catch |e| {
+                std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+                return e;
+            };
+
+            continue;
+        }
+
+        const exp: usize = 0;
+        std.testing.expectEqual(exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+    }
+}
+
+test "nth pseudo class" {
+    const alloc = std.testing.allocator;
+
+    var matcher = Matcher.init(alloc);
+    defer matcher.deinit();
+
+    var p1: Node = .{ .name = "p" };
+    var p2: Node = .{ .name = "p" };
+
+    p1.sibling = &p2;
+    p2.prev = &p1;
+
+    var root: Node = .{ .child = &p1, .last = &p2 };
+    p1.par = &root;
+    p2.par = &root;
+
+    const testcases = [_]struct {
+        q: []const u8,
+        n: Node,
+        exp: ?*const Node,
+    }{
+        .{ .q = "a:nth-of-type(1)", .n = root, .exp = null },
+        .{ .q = "p:nth-of-type(1)", .n = root, .exp = &p1 },
+        .{ .q = "p:nth-of-type(2)", .n = root, .exp = &p2 },
+        .{ .q = "p:nth-of-type(0)", .n = root, .exp = null },
+        .{ .q = "p:nth-of-type(2n)", .n = root, .exp = &p2 },
+        .{ .q = "p:nth-last-child(1)", .n = root, .exp = &p2 },
+        .{ .q = "p:nth-last-child(2)", .n = root, .exp = &p1 },
+        .{ .q = "p:nth-child(1)", .n = root, .exp = &p1 },
+        .{ .q = "p:nth-child(2)", .n = root, .exp = &p2 },
+        .{ .q = "p:nth-child(odd)", .n = root, .exp = &p1 },
+        .{ .q = "p:nth-child(even)", .n = root, .exp = &p2 },
+        .{ .q = "p:nth-child(n+2)", .n = root, .exp = &p2 },
+    };
+
+    for (testcases) |tc| {
+        matcher.reset();
+
+        const s = try css.parse(alloc, tc.q, .{});
+        defer s.deinit(alloc);
+
+        css.matchAll(s, &tc.n, &matcher) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+
+        if (tc.exp) |exp_n| {
+            const exp: usize = 1;
+            std.testing.expectEqual(exp, matcher.nodes.items.len) catch |e| {
+                std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+                return e;
+            };
+
+            std.testing.expectEqual(exp_n, matcher.nodes.items[0]) catch |e| {
+                std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+                return e;
+            };
+
+            continue;
+        }
+
+        const exp: usize = 0;
+        std.testing.expectEqual(exp, matcher.nodes.items.len) catch |e| {
+            std.debug.print("query: {s}, parsed selector: {any}\n", .{ tc.q, s });
+            return e;
+        };
+    }
+}
--- a/src/browser/css/parser.zig
+++ b/src/browser/css/parser.zig
@@ -0,0 +1,985 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// CSS Selector parser
+// This file is a rewrite in Zig of Cascadia CSS Selector parser.
+// see https://github.com/andybalholm/cascadia
+// see https://github.com/andybalholm/cascadia/blob/master/parser.go
+const std = @import("std");
+const ascii = std.ascii;
+
+const selector = @import("selector.zig");
+const Selector = selector.Selector;
+const PseudoClass = selector.PseudoClass;
+const AttributeOP = selector.AttributeOP;
+const Combinator = selector.Combinator;
+
+const REPLACEMENT_CHARACTER = &.{ 239, 191, 189 };
+
+pub const ParseError = error{
+    ExpectedSelector,
+    ExpectedIdentifier,
+    ExpectedName,
+    ExpectedIDSelector,
+    ExpectedClassSelector,
+    ExpectedAttributeSelector,
+    ExpectedString,
+    ExpectedRegexp,
+    ExpectedPseudoClassSelector,
+    ExpectedParenthesis,
+    ExpectedParenthesisClose,
+    ExpectedNthExpression,
+    ExpectedInteger,
+    InvalidEscape,
+    EscapeLineEndingOutsideString,
+    InvalidUnicode,
+    UnicodeIsNotHandled,
+    WriteError,
+    PseudoElementNotAtSelectorEnd,
+    PseudoElementNotUnique,
+    PseudoElementDisabled,
+    InvalidAttributeOperator,
+    InvalidAttributeSelector,
+    InvalidString,
+    InvalidRegexp,
+    InvalidPseudoClassSelector,
+    EmptyPseudoClassSelector,
+    InvalidPseudoClass,
+    InvalidPseudoElement,
+    UnmatchParenthesis,
+    NotHandled,
+    UnknownPseudoSelector,
+    InvalidNthExpression,
+} || PseudoClass.Error || Combinator.Error || std.mem.Allocator.Error;
+
+pub const ParseOptions = struct {
+    accept_pseudo_elts: bool = true,
+};
+
+pub const Parser = struct {
+    s: []const u8, // string to parse
+    i: usize = 0, // current position
+
+    opts: ParseOptions,
+
+    pub fn parse(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        return p.parseSelectorGroup(alloc);
+    }
+
+    // skipWhitespace consumes whitespace characters and comments.
+    // It returns true if there was actually anything to skip.
+    fn skipWhitespace(p: *Parser) bool {
+        var i = p.i;
+        while (i < p.s.len) {
+            const c = p.s[i];
+            // Whitespaces.
+            if (ascii.isWhitespace(c)) {
+                i += 1;
+                continue;
+            }
+
+            // Comments.
+            if (c == '/') {
+                if (std.mem.startsWith(u8, p.s[i..], "/*")) {
+                    if (std.mem.indexOf(u8, p.s[i..], "*/")) |end| {
+                        i += end + "*/".len;
+                        continue;
+                    }
+                }
+            }
+            break;
+        }
+
+        if (i > p.i) {
+            p.i = i;
+            return true;
+        }
+
+        return false;
+    }
+
+    // parseSimpleSelectorSequence parses a selector sequence that applies to
+    // a single element.
+    fn parseSimpleSelectorSequence(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        if (p.i >= p.s.len) {
+            return ParseError.ExpectedSelector;
+        }
+
+        var buf = std.ArrayList(Selector).init(alloc);
+        defer buf.deinit();
+
+        switch (p.s[p.i]) {
+            '*' => {
+                // It's the universal selector. Just skip over it, since it
+                // doesn't affect the meaning.
+                p.i += 1;
+
+                // other version of universal selector
+                if (p.i + 2 < p.s.len and std.mem.eql(u8, "|*", p.s[p.i .. p.i + 2])) {
+                    p.i += 2;
+                }
+            },
+            '#', '.', '[', ':' => {
+                // There's no type selector. Wait to process the other till the
+                // main loop.
+            },
+            else => try buf.append(try p.parseTypeSelector(alloc)),
+        }
+
+        var pseudo_elt: ?PseudoClass = null;
+
+        loop: while (p.i < p.s.len) {
+            var ns: Selector = switch (p.s[p.i]) {
+                '#' => try p.parseIDSelector(alloc),
+                '.' => try p.parseClassSelector(alloc),
+                '[' => try p.parseAttributeSelector(alloc),
+                ':' => try p.parsePseudoclassSelector(alloc),
+                else => break :loop,
+            };
+            errdefer ns.deinit(alloc);
+
+            // From https://drafts.csswg.org/selectors-3/#pseudo-elements :
+            // "Only one pseudo-element may appear per selector, and if present
+            // it must appear after the sequence of simple selectors that
+            // represents the subjects of the selector.""
+            switch (ns) {
+                .pseudo_element => |e| {
+                    //  We found a pseudo-element.
+                    //  Only one pseudo-element is accepted per selector.
+                    if (pseudo_elt != null) return ParseError.PseudoElementNotUnique;
+                    if (!p.opts.accept_pseudo_elts) return ParseError.PseudoElementDisabled;
+
+                    pseudo_elt = e;
+                    ns.deinit(alloc);
+                },
+                else => {
+                    if (pseudo_elt != null) return ParseError.PseudoElementNotAtSelectorEnd;
+                    try buf.append(ns);
+                },
+            }
+        }
+
+        // no need wrap the selectors in compoundSelector
+        if (buf.items.len == 1 and pseudo_elt == null) return buf.items[0];
+
+        return .{ .compound = .{ .selectors = try buf.toOwnedSlice(), .pseudo_elt = pseudo_elt } };
+    }
+
+    // parseTypeSelector parses a type selector (one that matches by tag name).
+    fn parseTypeSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        var buf = std.ArrayList(u8).init(alloc);
+        defer buf.deinit();
+        try p.parseIdentifier(buf.writer());
+
+        return .{ .tag = try buf.toOwnedSlice() };
+    }
+
+    // parseIdentifier parses an identifier.
+    fn parseIdentifier(p: *Parser, w: anytype) ParseError!void {
+        const prefix = '-';
+        var numPrefix: usize = 0;
+
+        while (p.s.len > p.i and p.s[p.i] == prefix) {
+            p.i += 1;
+            numPrefix += 1;
+        }
+
+        if (p.s.len <= p.i) {
+            return ParseError.ExpectedSelector;
+        }
+
+        const c = p.s[p.i];
+        if (!(nameStart(c) or c == '\\')) {
+            return ParseError.ExpectedSelector;
+        }
+
+        var ii: usize = 0;
+        while (ii < numPrefix) {
+            w.writeByte(prefix) catch return ParseError.WriteError;
+            ii += 1;
+        }
+        try parseName(p, w);
+    }
+
+    // parseName parses a name (which is like an identifier, but doesn't have
+    // extra restrictions on the first character).
+    fn parseName(p: *Parser, w: anytype) ParseError!void {
+        const sel = p.s;
+        const sel_len = sel.len;
+
+        var i = p.i;
+        var ok = false;
+
+        while (i < sel_len) {
+            const c = sel[i];
+
+            if (nameChar(c)) {
+                const start = i;
+                while (i < sel_len and nameChar(sel[i])) i += 1;
+                w.writeAll(sel[start..i]) catch return ParseError.WriteError;
+                ok = true;
+            } else if (c == '\\') {
+                p.i = i;
+                try p.parseEscape(w);
+                i = p.i;
+                ok = true;
+            } else if (c == 0) {
+                w.writeAll(REPLACEMENT_CHARACTER) catch return ParseError.WriteError;
+                i += 1;
+                if (i == sel_len) {
+                    ok = true;
+                }
+            } else {
+                // default:
+                break;
+            }
+        }
+
+        if (!ok) return ParseError.ExpectedName;
+        p.i = i;
+    }
+
+    // parseEscape parses a backslash escape.
+    // The returned string is owned by the caller.
+    fn parseEscape(p: *Parser, w: anytype) ParseError!void {
+        const sel = p.s;
+        const sel_len = sel.len;
+
+        if (sel_len < p.i + 2 or sel[p.i] != '\\') {
+            p.i += 1;
+            w.writeAll(REPLACEMENT_CHARACTER) catch return ParseError.WriteError;
+            return;
+        }
+
+        const start = p.i + 1;
+        const c = sel[start];
+
+        // unicode escape (hex)
+        if (ascii.isHex(c)) {
+            var i: usize = start;
+            while (i < start + 6 and i < sel_len and ascii.isHex(sel[i])) {
+                i += 1;
+            }
+
+            const v = std.fmt.parseUnsigned(u21, sel[start..i], 16) catch {
+                p.i = i;
+                w.writeAll(REPLACEMENT_CHARACTER) catch return ParseError.WriteError;
+                return;
+            };
+
+            if (sel_len >= i) {
+                if (sel_len > i) {
+                    switch (sel[i]) {
+                        '\r' => {
+                            i += 1;
+                            if (sel_len > i and sel[i] == '\n') i += 1;
+                        },
+                        ' ', '\t', '\n', std.ascii.control_code.ff => i += 1,
+                        else => {},
+                    }
+                }
+                p.i = i;
+                if (v == 0) {
+                    w.writeAll(REPLACEMENT_CHARACTER) catch return ParseError.WriteError;
+                    return;
+                }
+                var buf: [4]u8 = undefined;
+                const ln = std.unicode.utf8Encode(v, &buf) catch {
+                    w.writeAll(REPLACEMENT_CHARACTER) catch return ParseError.WriteError;
+                    return;
+                };
+                w.writeAll(buf[0..ln]) catch return ParseError.WriteError;
+                return;
+            }
+        }
+
+        // Return the literal character after the backslash.
+        p.i += 2;
+        w.writeByte(sel[start]) catch return ParseError.WriteError;
+    }
+
+    // parseIDSelector parses a selector that matches by id attribute.
+    fn parseIDSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        if (p.i >= p.s.len) return ParseError.ExpectedIDSelector;
+        if (p.s[p.i] != '#') return ParseError.ExpectedIDSelector;
+
+        p.i += 1;
+
+        var buf = std.ArrayList(u8).init(alloc);
+        defer buf.deinit();
+
+        try p.parseName(buf.writer());
+        return .{ .id = try buf.toOwnedSlice() };
+    }
+
+    // parseClassSelector parses a selector that matches by class attribute.
+    fn parseClassSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        if (p.i >= p.s.len) return ParseError.ExpectedClassSelector;
+        if (p.s[p.i] != '.') return ParseError.ExpectedClassSelector;
+
+        p.i += 1;
+
+        var buf = std.ArrayList(u8).init(alloc);
+        defer buf.deinit();
+
+        try p.parseIdentifier(buf.writer());
+        return .{ .class = try buf.toOwnedSlice() };
+    }
+
+    // parseAttributeSelector parses a selector that matches by attribute value.
+    fn parseAttributeSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        if (p.i >= p.s.len) return ParseError.ExpectedAttributeSelector;
+        if (p.s[p.i] != '[') return ParseError.ExpectedAttributeSelector;
+
+        p.i += 1;
+        _ = p.skipWhitespace();
+
+        var buf = std.ArrayList(u8).init(alloc);
+        defer buf.deinit();
+
+        try p.parseIdentifier(buf.writer());
+        const key = try buf.toOwnedSlice();
+        errdefer alloc.free(key);
+
+        lowerstr(key);
+
+        _ = p.skipWhitespace();
+        if (p.i >= p.s.len) return ParseError.ExpectedAttributeSelector;
+        if (p.s[p.i] == ']') {
+            p.i += 1;
+            return .{ .attribute = .{ .key = key } };
+        }
+
+        if (p.i + 2 >= p.s.len) return ParseError.ExpectedAttributeSelector;
+
+        const op = try parseAttributeOP(p.s[p.i .. p.i + 2]);
+        p.i += op.len();
+
+        _ = p.skipWhitespace();
+        if (p.i >= p.s.len) return ParseError.ExpectedAttributeSelector;
+
+        buf.clearRetainingCapacity();
+        var is_val: bool = undefined;
+        if (op == .regexp) {
+            is_val = false;
+            try p.parseRegex(buf.writer());
+        } else {
+            is_val = true;
+            switch (p.s[p.i]) {
+                '\'', '"' => try p.parseString(buf.writer()),
+                else => try p.parseIdentifier(buf.writer()),
+            }
+        }
+
+        _ = p.skipWhitespace();
+        if (p.i >= p.s.len) return ParseError.ExpectedAttributeSelector;
+
+        // check if the attribute contains an ignore case flag
+        var ci = false;
+        if (p.s[p.i] == 'i' or p.s[p.i] == 'I') {
+            ci = true;
+            p.i += 1;
+        }
+
+        _ = p.skipWhitespace();
+        if (p.i >= p.s.len) return ParseError.ExpectedAttributeSelector;
+
+        if (p.s[p.i] != ']') return ParseError.InvalidAttributeSelector;
+        p.i += 1;
+
+        return .{ .attribute = .{
+            .key = key,
+            .val = if (is_val) try buf.toOwnedSlice() else null,
+            .regexp = if (!is_val) try buf.toOwnedSlice() else null,
+            .op = op,
+            .ci = ci,
+        } };
+    }
+
+    // parseString parses a single- or double-quoted string.
+    fn parseString(p: *Parser, writer: anytype) ParseError!void {
+        const sel = p.s;
+        const sel_len = sel.len;
+
+        var i = p.i;
+        if (sel_len < i + 2) return ParseError.ExpectedString;
+
+        const quote = sel[i];
+        i += 1;
+
+        loop: while (i < sel_len) {
+            switch (sel[i]) {
+                '\\' => {
+                    if (sel_len > i + 1) {
+                        const c = sel[i + 1];
+                        switch (c) {
+                            '\r' => {
+                                if (sel_len > i + 2 and sel[i + 2] == '\n') {
+                                    i += 3;
+                                    continue :loop;
+                                }
+                                i += 2;
+                                continue :loop;
+                            },
+                            '\n', std.ascii.control_code.ff => {
+                                i += 2;
+                                continue :loop;
+                            },
+                            else => {},
+                        }
+                    }
+                    p.i = i;
+                    try p.parseEscape(writer);
+                    i = p.i;
+                },
+                '\r', '\n', std.ascii.control_code.ff => return ParseError.InvalidString,
+                else => |c| {
+                    if (c == quote) break :loop;
+                    const start = i;
+                    while (i < sel_len) {
+                        const cc = sel[i];
+                        if (cc == quote or cc == '\\' or c == '\r' or c == '\n' or c == std.ascii.control_code.ff) break;
+                        i += 1;
+                    }
+                    writer.writeAll(sel[start..i]) catch return ParseError.WriteError;
+                },
+            }
+        }
+
+        if (i >= sel_len) return ParseError.InvalidString;
+
+        // Consume the final quote.
+        i += 1;
+        p.i = i;
+    }
+
+    // parseRegex parses a regular expression; the end is defined by encountering an
+    // unmatched closing ')' or ']' which is not consumed
+    fn parseRegex(p: *Parser, writer: anytype) ParseError!void {
+        var i = p.i;
+        if (p.s.len < i + 2) return ParseError.ExpectedRegexp;
+
+        // number of open parens or brackets;
+        // when it becomes negative, finished parsing regex
+        var open: isize = 0;
+
+        loop: while (i < p.s.len) {
+            switch (p.s[i]) {
+                '(', '[' => open += 1,
+                ')', ']' => {
+                    open -= 1;
+                    if (open < 0) break :loop;
+                },
+                else => {},
+            }
+            i += 1;
+        }
+
+        if (i >= p.s.len) return ParseError.InvalidRegexp;
+        writer.writeAll(p.s[p.i..i]) catch return ParseError.WriteError;
+        p.i = i;
+    }
+
+    // parsePseudoclassSelector parses a pseudoclass selector like :not(p) or a pseudo-element
+    // For backwards compatibility, both ':' and '::' prefix are allowed for pseudo-elements.
+    // https://drafts.csswg.org/selectors-3/#pseudo-elements
+    fn parsePseudoclassSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        if (p.i >= p.s.len) return ParseError.ExpectedPseudoClassSelector;
+        if (p.s[p.i] != ':') return ParseError.ExpectedPseudoClassSelector;
+
+        p.i += 1;
+
+        var must_pseudo_elt: bool = false;
+        if (p.i >= p.s.len) return ParseError.EmptyPseudoClassSelector;
+        if (p.s[p.i] == ':') { // we found a pseudo-element
+            must_pseudo_elt = true;
+            p.i += 1;
+        }
+
+        var buf = std.ArrayList(u8).init(alloc);
+        defer buf.deinit();
+
+        try p.parseIdentifier(buf.writer());
+
+        const pseudo_class = try PseudoClass.parse(buf.items);
+
+        // reset the buffer to reuse it.
+        buf.clearRetainingCapacity();
+
+        if (must_pseudo_elt and !pseudo_class.isPseudoElement()) return ParseError.InvalidPseudoElement;
+
+        switch (pseudo_class) {
+            .not, .has, .haschild => {
+                if (!p.consumeParenthesis()) return ParseError.ExpectedParenthesis;
+
+                const sel = try p.parseSelectorGroup(alloc);
+                if (!p.consumeClosingParenthesis()) return ParseError.ExpectedParenthesisClose;
+
+                const s = try alloc.create(Selector);
+                errdefer alloc.destroy(s);
+                s.* = sel;
+
+                return .{ .pseudo_class_relative = .{ .pseudo_class = pseudo_class, .match = s } };
+            },
+            .contains, .containsown => {
+                if (!p.consumeParenthesis()) return ParseError.ExpectedParenthesis;
+                if (p.i == p.s.len) return ParseError.UnmatchParenthesis;
+
+                switch (p.s[p.i]) {
+                    '\'', '"' => try p.parseString(buf.writer()),
+                    else => try p.parseString(buf.writer()),
+                }
+
+                _ = p.skipWhitespace();
+                if (p.i >= p.s.len) return ParseError.InvalidPseudoClass;
+                if (!p.consumeClosingParenthesis()) return ParseError.ExpectedParenthesisClose;
+
+                const val = try buf.toOwnedSlice();
+                errdefer alloc.free(val);
+
+                lowerstr(val);
+
+                return .{ .pseudo_class_contains = .{ .own = pseudo_class == .containsown, .val = val } };
+            },
+            .matches, .matchesown => {
+                if (!p.consumeParenthesis()) return ParseError.ExpectedParenthesis;
+
+                try p.parseRegex(buf.writer());
+                if (p.i >= p.s.len) return ParseError.InvalidPseudoClassSelector;
+                if (!p.consumeClosingParenthesis()) return ParseError.ExpectedParenthesisClose;
+
+                return .{ .pseudo_class_regexp = .{ .own = pseudo_class == .matchesown, .regexp = try buf.toOwnedSlice() } };
+            },
+            .nth_child, .nth_last_child, .nth_of_type, .nth_last_of_type => {
+                if (!p.consumeParenthesis()) return ParseError.ExpectedParenthesis;
+                const nth = try p.parseNth(alloc);
+                if (!p.consumeClosingParenthesis()) return ParseError.ExpectedParenthesisClose;
+
+                const last = pseudo_class == .nth_last_child or pseudo_class == .nth_last_of_type;
+                const of_type = pseudo_class == .nth_of_type or pseudo_class == .nth_last_of_type;
+                return .{ .pseudo_class_nth = .{ .a = nth[0], .b = nth[1], .of_type = of_type, .last = last } };
+            },
+            .first_child => return .{ .pseudo_class_nth = .{ .a = 0, .b = 1, .of_type = false, .last = false } },
+            .last_child => return .{ .pseudo_class_nth = .{ .a = 0, .b = 1, .of_type = false, .last = true } },
+            .first_of_type => return .{ .pseudo_class_nth = .{ .a = 0, .b = 1, .of_type = true, .last = false } },
+            .last_of_type => return .{ .pseudo_class_nth = .{ .a = 0, .b = 1, .of_type = true, .last = true } },
+            .only_child => return .{ .pseudo_class_only_child = false },
+            .only_of_type => return .{ .pseudo_class_only_child = true },
+            .input, .empty, .root, .link => return .{ .pseudo_class = pseudo_class },
+            .enabled, .disabled, .checked => return .{ .pseudo_class = pseudo_class },
+            .visible => return .{ .pseudo_class = pseudo_class },
+            .lang => {
+                if (!p.consumeParenthesis()) return ParseError.ExpectedParenthesis;
+                if (p.i == p.s.len) return ParseError.UnmatchParenthesis;
+
+                try p.parseIdentifier(buf.writer());
+
+                _ = p.skipWhitespace();
+                if (p.i >= p.s.len) return ParseError.InvalidPseudoClass;
+                if (!p.consumeClosingParenthesis()) return ParseError.ExpectedParenthesisClose;
+
+                const val = try buf.toOwnedSlice();
+                errdefer alloc.free(val);
+                lowerstr(val);
+
+                return .{ .pseudo_class_lang = val };
+            },
+            .visited, .hover, .active, .focus, .target => {
+                // Not applicable in a static context: never match.
+                return .{ .never_match = pseudo_class };
+            },
+            .after, .backdrop, .before, .cue, .first_letter => return .{ .pseudo_element = pseudo_class },
+            .first_line, .grammar_error, .marker, .placeholder => return .{ .pseudo_element = pseudo_class },
+            .selection, .spelling_error => return .{ .pseudo_element = pseudo_class },
+            .modal, .popover_open => return .{ .pseudo_element = pseudo_class },
+        }
+    }
+
+    // consumeParenthesis consumes an opening parenthesis and any following
+    // whitespace. It returns true if there was actually a parenthesis to skip.
+    fn consumeParenthesis(p: *Parser) bool {
+        if (p.i < p.s.len and p.s[p.i] == '(') {
+            p.i += 1;
+            _ = p.skipWhitespace();
+            return true;
+        }
+        return false;
+    }
+
+    // parseSelectorGroup parses a group of selectors, separated by commas.
+    fn parseSelectorGroup(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        const s = try p.parseSelector(alloc);
+
+        var buf = std.ArrayList(Selector).init(alloc);
+        defer buf.deinit();
+
+        try buf.append(s);
+
+        while (p.i < p.s.len) {
+            if (p.s[p.i] != ',') break;
+            p.i += 1;
+            const ss = try p.parseSelector(alloc);
+            try buf.append(ss);
+        }
+
+        if (buf.items.len == 1) return buf.items[0];
+
+        return .{ .group = try buf.toOwnedSlice() };
+    }
+
+    // parseSelector parses a selector that may include combinators.
+    fn parseSelector(p: *Parser, alloc: std.mem.Allocator) ParseError!Selector {
+        _ = p.skipWhitespace();
+        var s = try p.parseSimpleSelectorSequence(alloc);
+
+        while (true) {
+            var combinator: Combinator = .empty;
+            if (p.skipWhitespace()) {
+                combinator = .descendant;
+            }
+            if (p.i >= p.s.len) {
+                return s;
+            }
+
+            switch (p.s[p.i]) {
+                '+', '>', '~' => {
+                    combinator = try Combinator.parse(p.s[p.i]);
+                    p.i += 1;
+                    _ = p.skipWhitespace();
+                },
+                // These characters can't begin a selector, but they can legally occur after one.
+                ',', ')' => {
+                    return s;
+                },
+                else => {},
+            }
+
+            if (combinator == .empty) {
+                return s;
+            }
+
+            const c = try p.parseSimpleSelectorSequence(alloc);
+
+            const first = try alloc.create(Selector);
+            errdefer alloc.destroy(first);
+            first.* = s;
+
+            const second = try alloc.create(Selector);
+            errdefer alloc.destroy(second);
+            second.* = c;
+
+            s = Selector{ .combined = .{ .first = first, .second = second, .combinator = combinator } };
+        }
+
+        return s;
+    }
+
+    // consumeClosingParenthesis consumes a closing parenthesis and any preceding
+    // whitespace. It returns true if there was actually a parenthesis to skip.
+    fn consumeClosingParenthesis(p: *Parser) bool {
+        const i = p.i;
+        _ = p.skipWhitespace();
+        if (p.i < p.s.len and p.s[p.i] == ')') {
+            p.i += 1;
+            return true;
+        }
+        p.i = i;
+        return false;
+    }
+
+    // parseInteger parses a  decimal integer.
+    fn parseInteger(p: *Parser) ParseError!isize {
+        var i = p.i;
+        const start = i;
+        while (i < p.s.len and '0' <= p.s[i] and p.s[i] <= '9') i += 1;
+        if (i == start) return ParseError.ExpectedInteger;
+        p.i = i;
+
+        return std.fmt.parseUnsigned(isize, p.s[start..i], 10) catch ParseError.ExpectedInteger;
+    }
+
+    fn parseNthReadN(p: *Parser, a: isize) ParseError![2]isize {
+        _ = p.skipWhitespace();
+        if (p.i >= p.s.len) return ParseError.ExpectedNthExpression;
+
+        return switch (p.s[p.i]) {
+            '+' => {
+                p.i += 1;
+                _ = p.skipWhitespace();
+                const b = try p.parseInteger();
+                return .{ a, b };
+            },
+            '-' => {
+                p.i += 1;
+                _ = p.skipWhitespace();
+                const b = try p.parseInteger();
+                return .{ a, -b };
+            },
+            else => .{ a, 0 },
+        };
+    }
+
+    fn parseNthReadA(p: *Parser, a: isize) ParseError![2]isize {
+        if (p.i >= p.s.len) return ParseError.ExpectedNthExpression;
+        return switch (p.s[p.i]) {
+            'n', 'N' => {
+                p.i += 1;
+                return p.parseNthReadN(a);
+            },
+            else => .{ 0, a },
+        };
+    }
+
+    fn parseNthNegativeA(p: *Parser) ParseError![2]isize {
+        if (p.i >= p.s.len) return ParseError.ExpectedNthExpression;
+        const c = p.s[p.i];
+        if (std.ascii.isDigit(c)) {
+            const a = try p.parseInteger() * -1;
+            return p.parseNthReadA(a);
+        }
+        if (c == 'n' or c == 'N') {
+            p.i += 1;
+            return p.parseNthReadN(-1);
+        }
+
+        return ParseError.InvalidNthExpression;
+    }
+
+    fn parseNthPositiveA(p: *Parser) ParseError![2]isize {
+        if (p.i >= p.s.len) return ParseError.ExpectedNthExpression;
+        const c = p.s[p.i];
+        if (std.ascii.isDigit(c)) {
+            const a = try p.parseInteger();
+            return p.parseNthReadA(a);
+        }
+        if (c == 'n' or c == 'N') {
+            p.i += 1;
+            return p.parseNthReadN(1);
+        }
+
+        return ParseError.InvalidNthExpression;
+    }
+
+    // parseNth parses the argument for :nth-child (normally of the form an+b).
+    fn parseNth(p: *Parser, alloc: std.mem.Allocator) ParseError![2]isize {
+        // initial state
+        if (p.i >= p.s.len) return ParseError.ExpectedNthExpression;
+        return switch (p.s[p.i]) {
+            '-' => {
+                p.i += 1;
+                return p.parseNthNegativeA();
+            },
+            '+' => {
+                p.i += 1;
+                return p.parseNthPositiveA();
+            },
+            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' => p.parseNthPositiveA(),
+            'n', 'N' => {
+                p.i += 1;
+                return p.parseNthReadN(1);
+            },
+            'o', 'O', 'e', 'E' => {
+                var buf = std.ArrayList(u8).init(alloc);
+                defer buf.deinit();
+
+                try p.parseName(buf.writer());
+
+                if (std.ascii.eqlIgnoreCase("odd", buf.items)) return .{ 2, 1 };
+                if (std.ascii.eqlIgnoreCase("even", buf.items)) return .{ 2, 0 };
+
+                return ParseError.InvalidNthExpression;
+            },
+            else => ParseError.InvalidNthExpression,
+        };
+    }
+};
+
+// nameStart returns whether c can be the first character of an identifier
+// (not counting an initial hyphen, or an escape sequence).
+fn nameStart(c: u8) bool {
+    return 'a' <= c and c <= 'z' or 'A' <= c and c <= 'Z' or c == '_' or c > 127;
+}
+
+// nameChar returns whether c can be a character within an identifier
+// (not counting an escape sequence).
+fn nameChar(c: u8) bool {
+    return 'a' <= c and c <= 'z' or 'A' <= c and c <= 'Z' or c == '_' or c > 127 or
+        c == '-' or '0' <= c and c <= '9';
+}
+
+fn lowerstr(str: []u8) void {
+    for (str, 0..) |c, i| {
+        str[i] = std.ascii.toLower(c);
+    }
+}
+
+// parseAttributeOP parses an AttributeOP from a string of 1 or 2 bytes.
+fn parseAttributeOP(s: []const u8) ParseError!AttributeOP {
+    if (s.len < 1 or s.len > 2) return ParseError.InvalidAttributeOperator;
+
+    // if the first sign is equal, we don't check anything else.
+    if (s[0] == '=') return .eql;
+
+    if (s.len != 2 or s[1] != '=') return ParseError.InvalidAttributeOperator;
+
+    return switch (s[0]) {
+        '=' => .eql,
+        '!' => .not_eql,
+        '~' => .one_of,
+        '|' => .prefix_hyphen,
+        '^' => .prefix,
+        '$' => .suffix,
+        '*' => .contains,
+        '#' => .regexp,
+        else => ParseError.InvalidAttributeOperator,
+    };
+}
+
+test "parser.skipWhitespace" {
+    const testcases = [_]struct {
+        s: []const u8,
+        i: usize,
+        r: bool,
+    }{
+        .{ .s = "", .i = 0, .r = false },
+        .{ .s = "foo", .i = 0, .r = false },
+        .{ .s = " ", .i = 1, .r = true },
+        .{ .s = " foo", .i = 1, .r = true },
+        .{ .s = "/* foo */ bar", .i = 10, .r = true },
+        .{ .s = "/* foo", .i = 0, .r = false },
+    };
+
+    for (testcases) |tc| {
+        var p = Parser{ .s = tc.s, .opts = .{} };
+        const res = p.skipWhitespace();
+        try std.testing.expectEqual(tc.r, res);
+        try std.testing.expectEqual(tc.i, p.i);
+    }
+}
+
+test "parser.parseIdentifier" {
+    const alloc = std.testing.allocator;
+
+    const testcases = [_]struct {
+        s: []const u8, // given value
+        exp: []const u8, // expected value
+        err: bool = false,
+    }{
+        .{ .s = "x", .exp = "x" },
+        .{ .s = "96", .exp = "", .err = true },
+        .{ .s = "-x", .exp = "-x" },
+        .{ .s = "r\\e9 sumé", .exp = "résumé" },
+        .{ .s = "r\\0000e9 sumé", .exp = "résumé" },
+        .{ .s = "r\\0000e9sumé", .exp = "résumé" },
+        .{ .s = "a\\\"b", .exp = "a\"b" },
+    };
+
+    var buf = std.ArrayList(u8).init(alloc);
+    defer buf.deinit();
+
+    for (testcases) |tc| {
+        buf.clearRetainingCapacity();
+
+        var p = Parser{ .s = tc.s, .opts = .{} };
+        p.parseIdentifier(buf.writer()) catch |e| {
+            // if error was expected, continue.
+            if (tc.err) continue;
+
+            std.debug.print("test case {s}\n", .{tc.s});
+            return e;
+        };
+        std.testing.expectEqualDeep(tc.exp, buf.items) catch |e| {
+            std.debug.print("test case {s} : {s}\n", .{ tc.s, buf.items });
+            return e;
+        };
+    }
+}
+
+test "parser.parseString" {
+    const alloc = std.testing.allocator;
+
+    const testcases = [_]struct {
+        s: []const u8, // given value
+        exp: []const u8, // expected value
+        err: bool = false,
+    }{
+        .{ .s = "\"x\"", .exp = "x" },
+        .{ .s = "'x'", .exp = "x" },
+        .{ .s = "'x", .exp = "", .err = true },
+        .{ .s = "'x\\\r\nx'", .exp = "xx" },
+        .{ .s = "\"r\\e9 sumé\"", .exp = "résumé" },
+        .{ .s = "\"r\\0000e9 sumé\"", .exp = "résumé" },
+        .{ .s = "\"r\\0000e9sumé\"", .exp = "résumé" },
+        .{ .s = "\"a\\\"b\"", .exp = "a\"b" },
+        .{ .s = "\"\\\n\"", .exp = "" },
+        .{ .s = "\"hello world\"", .exp = "hello world" },
+    };
+
+    var buf = std.ArrayList(u8).init(alloc);
+    defer buf.deinit();
+
+    for (testcases) |tc| {
+        buf.clearRetainingCapacity();
+
+        var p = Parser{ .s = tc.s, .opts = .{} };
+        p.parseString(buf.writer()) catch |e| {
+            // if error was expected, continue.
+            if (tc.err) continue;
+
+            std.debug.print("test case {s}\n", .{tc.s});
+            return e;
+        };
+        std.testing.expectEqualDeep(tc.exp, buf.items) catch |e| {
+            std.debug.print("test case {s} : {s}\n", .{ tc.s, buf.items });
+            return e;
+        };
+    }
+}
+
+test "parser.parse" {
+    var arena = std.heap.ArenaAllocator.init(std.testing.allocator);
+    defer arena.deinit();
+    const alloc = arena.allocator();
+
+    const testcases = [_]struct {
+        s: []const u8, // given value
+        exp: Selector, // expected value
+        err: bool = false,
+    }{
+        .{ .s = "root", .exp = .{ .tag = "root" } },
+        .{ .s = ".root", .exp = .{ .class = "root" } },
+        .{ .s = ":root", .exp = .{ .pseudo_class = .root } },
+        .{ .s = ".\\:bar", .exp = .{ .class = ":bar" } },
+        .{ .s = ".foo\\:bar", .exp = .{ .class = "foo:bar" } },
+    };
+
+    for (testcases) |tc| {
+        var p = Parser{ .s = tc.s, .opts = .{} };
+        const sel = p.parse(alloc) catch |e| {
+            // if error was expected, continue.
+            if (tc.err) continue;
+
+            std.debug.print("test case {s}\n", .{tc.s});
+            return e;
+        };
+        std.testing.expectEqualDeep(tc.exp, sel) catch |e| {
+            std.debug.print("test case {s} : {}\n", .{ tc.s, sel });
+            return e;
+        };
+    }
+}
--- a/src/browser/css/selector.zig
+++ b/src/browser/css/selector.zig
@@ -0,0 +1,829 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+pub const AttributeOP = enum {
+    eql, // =
+    not_eql, // !=
+    one_of, // ~=
+    prefix_hyphen, // |=
+    prefix, // ^=
+    suffix, // $=
+    contains, // *=
+    regexp, // #=
+
+    pub fn len(op: AttributeOP) u2 {
+        if (op == .eql) return 1;
+        return 2;
+    }
+};
+
+pub const Combinator = enum {
+    empty,
+    descendant, // space
+    child, // >
+    next_sibling, // +
+    subsequent_sibling, // ~
+
+    pub const Error = error{
+        InvalidCombinator,
+    };
+
+    pub fn parse(c: u8) Error!Combinator {
+        return switch (c) {
+            ' ' => .descendant,
+            '>' => .child,
+            '+' => .next_sibling,
+            '~' => .subsequent_sibling,
+            else => Error.InvalidCombinator,
+        };
+    }
+};
+
+pub const PseudoClass = enum {
+    not,
+    has,
+    haschild,
+    contains,
+    containsown,
+    matches,
+    matchesown,
+    nth_child,
+    nth_last_child,
+    nth_of_type,
+    nth_last_of_type,
+    first_child,
+    last_child,
+    first_of_type,
+    last_of_type,
+    only_child,
+    only_of_type,
+    input,
+    empty,
+    root,
+    link,
+    lang,
+    enabled,
+    disabled,
+    checked,
+    visited,
+    hover,
+    active,
+    focus,
+    target,
+    after,
+    backdrop,
+    before,
+    cue,
+    first_letter,
+    first_line,
+    grammar_error,
+    marker,
+    placeholder,
+    selection,
+    spelling_error,
+    modal,
+    popover_open,
+    visible,
+
+    pub const Error = error{
+        InvalidPseudoClass,
+    };
+
+    pub fn isPseudoElement(pc: PseudoClass) bool {
+        return switch (pc) {
+            .after, .backdrop, .before, .cue, .first_letter => true,
+            .first_line, .grammar_error, .marker, .placeholder => true,
+            .selection, .spelling_error => true,
+            else => false,
+        };
+    }
+
+    pub fn parse(s: []const u8) Error!PseudoClass {
+        const longest_selector = "nth-last-of-type";
+        if (s.len > longest_selector.len) {
+            return Error.InvalidPseudoClass;
+        }
+
+        var buf: [longest_selector.len]u8 = undefined;
+        const selector = std.ascii.lowerString(&buf, s);
+
+        switch (selector.len) {
+            3 => switch (@as(u24, @bitCast(selector[0..3].*))) {
+                asUint(u24, "cue") => return .cue,
+                asUint(u24, "has") => return .has,
+                asUint(u24, "not") => return .not,
+                else => {},
+            },
+            4 => switch (@as(u32, @bitCast(selector[0..4].*))) {
+                asUint(u32, "lang") => return .lang,
+                asUint(u32, "link") => return .link,
+                asUint(u32, "root") => return .root,
+                else => {},
+            },
+            5 => switch (@as(u40, @bitCast(selector[0..5].*))) {
+                asUint(u40, "after") => return .after,
+                asUint(u40, "empty") => return .empty,
+                asUint(u40, "focus") => return .focus,
+                asUint(u40, "hover") => return .hover,
+                asUint(u40, "input") => return .input,
+                asUint(u40, "modal") => return .modal,
+                else => {},
+            },
+            6 => switch (@as(u48, @bitCast(selector[0..6].*))) {
+                asUint(u48, "active") => return .active,
+                asUint(u48, "before") => return .before,
+                asUint(u48, "marker") => return .marker,
+                asUint(u48, "target") => return .target,
+                else => {},
+            },
+            7 => switch (@as(u56, @bitCast(selector[0..7].*))) {
+                asUint(u56, "checked") => return .checked,
+                asUint(u56, "enabled") => return .enabled,
+                asUint(u56, "matches") => return .matches,
+                asUint(u56, "visited") => return .visited,
+                asUint(u56, "visible") => return .visible,
+                else => {},
+            },
+            8 => switch (@as(u64, @bitCast(selector[0..8].*))) {
+                asUint(u64, "backdrop") => return .backdrop,
+                asUint(u64, "contains") => return .contains,
+                asUint(u64, "disabled") => return .disabled,
+                asUint(u64, "haschild") => return .haschild,
+                else => {},
+            },
+            9 => switch (@as(u72, @bitCast(selector[0..9].*))) {
+                asUint(u72, "nth-child") => return .nth_child,
+                asUint(u72, "selection") => return .selection,
+                else => {},
+            },
+            10 => switch (@as(u80, @bitCast(selector[0..10].*))) {
+                asUint(u80, "first-line") => return .first_line,
+                asUint(u80, "last-child") => return .last_child,
+                asUint(u80, "matchesown") => return .matchesown,
+                asUint(u80, "only-child") => return .only_child,
+                else => {},
+            },
+            11 => switch (@as(u88, @bitCast(selector[0..11].*))) {
+                asUint(u88, "containsown") => return .containsown,
+                asUint(u88, "first-child") => return .first_child,
+                asUint(u88, "nth-of-type") => return .nth_of_type,
+                asUint(u88, "placeholder") => return .placeholder,
+                else => {},
+            },
+            12 => switch (@as(u96, @bitCast(selector[0..12].*))) {
+                asUint(u96, "first-letter") => return .first_letter,
+                asUint(u96, "last-of-type") => return .last_of_type,
+                asUint(u96, "only-of-type") => return .only_of_type,
+                asUint(u96, "popover-open") => return .popover_open,
+                else => {},
+            },
+            13 => switch (@as(u104, @bitCast(selector[0..13].*))) {
+                asUint(u104, "first-of-type") => return .first_of_type,
+                asUint(u104, "grammar-error") => return .grammar_error,
+                else => {},
+            },
+            14 => switch (@as(u112, @bitCast(selector[0..14].*))) {
+                asUint(u112, "nth-last-child") => return .nth_last_child,
+                asUint(u112, "spelling-error") => return .spelling_error,
+                else => {},
+            },
+            16 => switch (@as(u128, @bitCast(selector[0..16].*))) {
+                asUint(u128, "nth-last-of-type") => return .nth_last_of_type,
+                else => {},
+            },
+            else => {},
+        }
+        return Error.InvalidPseudoClass;
+    }
+};
+
+fn asUint(comptime T: type, comptime string: []const u8) T {
+    return @bitCast(string[0..string.len].*);
+}
+
+pub const Selector = union(enum) {
+    pub const Error = error{
+        UnknownCombinedCombinator,
+        UnsupportedRelativePseudoClass,
+        UnsupportedContainsPseudoClass,
+        UnsupportedPseudoClass,
+        UnsupportedPseudoElement,
+        UnsupportedRegexpPseudoClass,
+        UnsupportedAttrRegexpOperator,
+    };
+
+    compound: struct {
+        selectors: []Selector,
+        pseudo_elt: ?PseudoClass,
+    },
+    group: []Selector,
+    tag: []const u8,
+    id: []const u8,
+    class: []const u8,
+    attribute: struct {
+        key: []const u8,
+        val: ?[]const u8 = null,
+        op: ?AttributeOP = null,
+        regexp: ?[]const u8 = null,
+        ci: bool = false,
+    },
+    combined: struct {
+        first: *Selector,
+        second: *Selector,
+        combinator: Combinator,
+    },
+
+    never_match: PseudoClass,
+
+    pseudo_class: PseudoClass,
+    pseudo_class_only_child: bool,
+    pseudo_class_lang: []const u8,
+    pseudo_class_relative: struct {
+        pseudo_class: PseudoClass,
+        match: *Selector,
+    },
+    pseudo_class_contains: struct {
+        own: bool,
+        val: []const u8,
+    },
+    pseudo_class_regexp: struct {
+        own: bool,
+        regexp: []const u8,
+    },
+    pseudo_class_nth: struct {
+        a: isize,
+        b: isize,
+        of_type: bool,
+        last: bool,
+    },
+    pseudo_element: PseudoClass,
+
+    // returns true if s is a whitespace-separated list that includes val.
+    fn word(haystack: []const u8, needle: []const u8, ci: bool) bool {
+        if (haystack.len == 0) return false;
+        var it = std.mem.splitAny(u8, haystack, " \t\r\n"); // TODO add \f
+        while (it.next()) |part| {
+            if (eql(part, needle, ci)) return true;
+        }
+        return false;
+    }
+
+    fn eql(a: []const u8, b: []const u8, ci: bool) bool {
+        if (ci) return std.ascii.eqlIgnoreCase(a, b);
+        return std.mem.eql(u8, a, b);
+    }
+
+    fn starts(haystack: []const u8, needle: []const u8, ci: bool) bool {
+        if (ci) return std.ascii.startsWithIgnoreCase(haystack, needle);
+        return std.mem.startsWith(u8, haystack, needle);
+    }
+
+    fn ends(haystack: []const u8, needle: []const u8, ci: bool) bool {
+        if (ci) return std.ascii.endsWithIgnoreCase(haystack, needle);
+        return std.mem.endsWith(u8, haystack, needle);
+    }
+
+    fn contains(haystack: []const u8, needle: []const u8, ci: bool) bool {
+        if (ci) return std.ascii.indexOfIgnoreCase(haystack, needle) != null;
+        return std.mem.indexOf(u8, haystack, needle) != null;
+    }
+
+    // match returns true if the node matches the selector query.
+    pub fn match(s: Selector, n: anytype) !bool {
+        return switch (s) {
+            .tag => |v| n.isElement() and std.ascii.eqlIgnoreCase(v, try n.tag()),
+            .id => |v| return n.isElement() and std.mem.eql(u8, v, try n.attr("id") orelse return false),
+            .class => |v| return n.isElement() and word(try n.attr("class") orelse return false, v, false),
+            .group => |v| {
+                for (v) |sel| {
+                    if (try sel.match(n)) return true;
+                }
+                return false;
+            },
+            .compound => |v| {
+                if (v.selectors.len == 0) return n.isElement();
+
+                for (v.selectors) |sel| {
+                    if (!try sel.match(n)) return false;
+                }
+                return true;
+            },
+            .combined => |v| {
+                return switch (v.combinator) {
+                    .empty => try v.first.match(n),
+                    .descendant => {
+                        if (!try v.second.match(n)) return false;
+
+                        // The first must match a ascendent.
+                        var p = try n.parent();
+                        while (p != null) {
+                            if (try v.first.match(p.?)) {
+                                return true;
+                            }
+                            p = try p.?.parent();
+                        }
+
+                        return false;
+                    },
+                    .child => {
+                        const p = try n.parent();
+                        if (p == null) return false;
+
+                        return try v.second.match(n) and try v.first.match(p.?);
+                    },
+                    .next_sibling => {
+                        if (!try v.second.match(n)) return false;
+                        var c = try n.prevSibling();
+                        while (c != null) {
+                            if (c.?.isText() or c.?.isComment()) {
+                                c = try c.?.prevSibling();
+                                continue;
+                            }
+                            return try v.first.match(c.?);
+                        }
+                        return false;
+                    },
+                    .subsequent_sibling => {
+                        if (!try v.second.match(n)) return false;
+
+                        var c = try n.prevSibling();
+                        while (c != null) {
+                            if (try v.first.match(c.?)) return true;
+                            c = try c.?.prevSibling();
+                        }
+                        return false;
+                    },
+                };
+            },
+            .attribute => |v| {
+                var attr = try n.attr(v.key);
+
+                if (v.op == null) return attr != null;
+                if (v.val == null or v.val.?.len == 0) return false;
+
+                const val = v.val.?;
+
+                return switch (v.op.?) {
+                    .eql => attr != null and eql(attr.?, val, v.ci),
+                    .not_eql => attr == null or !eql(attr.?, val, v.ci),
+                    .one_of => attr != null and word(attr.?, val, v.ci),
+                    .prefix => {
+                        if (attr == null) return false;
+                        attr.? = std.mem.trim(u8, attr.?, &std.ascii.whitespace);
+
+                        if (attr.?.len == 0) return false;
+
+                        return starts(attr.?, val, v.ci);
+                    },
+                    .suffix => {
+                        if (attr == null) return false;
+                        attr.? = std.mem.trim(u8, attr.?, &std.ascii.whitespace);
+
+                        if (attr.?.len == 0) return false;
+
+                        return ends(attr.?, val, v.ci);
+                    },
+                    .contains => {
+                        if (attr == null) return false;
+                        attr.? = std.mem.trim(u8, attr.?, &std.ascii.whitespace);
+
+                        if (attr.?.len == 0) return false;
+
+                        return contains(attr.?, val, v.ci);
+                    },
+                    .prefix_hyphen => {
+                        if (attr == null) return false;
+                        if (eql(attr.?, val, v.ci)) return true;
+
+                        if (attr.?.len <= val.len) return false;
+
+                        if (!starts(attr.?, val, v.ci)) return false;
+
+                        return attr.?[val.len] == '-';
+                    },
+                    .regexp => return Error.UnsupportedAttrRegexpOperator, // TODO handle regexp attribute operator.
+                };
+            },
+            .never_match => return false,
+            .pseudo_class_relative => |v| {
+                if (!n.isElement()) return false;
+
+                return switch (v.pseudo_class) {
+                    .not => !try v.match.match(n),
+                    .has => try hasDescendantMatch(v.match, n),
+                    .haschild => try hasChildMatch(v.match, n),
+                    else => Error.UnsupportedRelativePseudoClass,
+                };
+            },
+            .pseudo_class_contains => return Error.UnsupportedContainsPseudoClass, // TODO, need mem allocation.
+            .pseudo_class_regexp => return Error.UnsupportedRegexpPseudoClass, // TODO need mem allocation.
+            .pseudo_class_nth => |v| {
+                if (v.a == 0) {
+                    if (v.last) {
+                        return simpleNthLastChildMatch(v.b, v.of_type, n);
+                    }
+                    return simpleNthChildMatch(v.b, v.of_type, n);
+                }
+                return nthChildMatch(v.a, v.b, v.last, v.of_type, n);
+            },
+            .pseudo_class => |v| {
+                return switch (v) {
+                    .input => {
+                        if (!n.isElement()) return false;
+                        const ntag = try n.tag();
+
+                        return std.ascii.eqlIgnoreCase("input", ntag) or
+                            std.ascii.eqlIgnoreCase("select", ntag) or
+                            std.ascii.eqlIgnoreCase("button", ntag) or
+                            std.ascii.eqlIgnoreCase("textarea", ntag);
+                    },
+                    .empty => {
+                        if (!n.isElement()) return false;
+
+                        var c = try n.firstChild();
+                        while (c != null) {
+                            if (c.?.isElement()) return false;
+
+                            if (c.?.isText()) {
+                                if (try c.?.isEmptyText()) continue;
+                                return false;
+                            }
+
+                            c = try c.?.nextSibling();
+                        }
+
+                        return true;
+                    },
+                    .root => {
+                        if (!n.isElement()) return false;
+
+                        const p = try n.parent();
+                        return (p != null and p.?.isDocument());
+                    },
+                    .link => {
+                        const ntag = try n.tag();
+
+                        return std.ascii.eqlIgnoreCase("a", ntag) or
+                            std.ascii.eqlIgnoreCase("area", ntag) or
+                            std.ascii.eqlIgnoreCase("link", ntag);
+                    },
+                    .enabled => {
+                        if (!n.isElement()) return false;
+
+                        const ntag = try n.tag();
+
+                        if (std.ascii.eqlIgnoreCase("a", ntag) or
+                            std.ascii.eqlIgnoreCase("area", ntag) or
+                            std.ascii.eqlIgnoreCase("link", ntag))
+                        {
+                            return try n.attr("href") != null;
+                        }
+
+                        if (std.ascii.eqlIgnoreCase("optgroup", ntag) or
+                            std.ascii.eqlIgnoreCase("menuitem", ntag) or
+                            std.ascii.eqlIgnoreCase("fieldset", ntag))
+                        {
+                            return try n.attr("disabled") == null;
+                        }
+
+                        if (std.ascii.eqlIgnoreCase("input", ntag) or
+                            std.ascii.eqlIgnoreCase("button", ntag) or
+                            std.ascii.eqlIgnoreCase("select", ntag) or
+                            std.ascii.eqlIgnoreCase("textarea", ntag) or
+                            std.ascii.eqlIgnoreCase("option", ntag))
+                        {
+                            return try n.attr("disabled") == null and
+                                !try inDisabledFieldset(n);
+                        }
+
+                        return false;
+                    },
+                    .disabled => {
+                        if (!n.isElement()) return false;
+
+                        const ntag = try n.tag();
+
+                        if (std.ascii.eqlIgnoreCase("optgroup", ntag) or
+                            std.ascii.eqlIgnoreCase("menuitem", ntag) or
+                            std.ascii.eqlIgnoreCase("fieldset", ntag))
+                        {
+                            return try n.attr("disabled") != null;
+                        }
+
+                        if (std.ascii.eqlIgnoreCase("input", ntag) or
+                            std.ascii.eqlIgnoreCase("button", ntag) or
+                            std.ascii.eqlIgnoreCase("select", ntag) or
+                            std.ascii.eqlIgnoreCase("textarea", ntag) or
+                            std.ascii.eqlIgnoreCase("option", ntag))
+                        {
+                            return try n.attr("disabled") != null or
+                                try inDisabledFieldset(n);
+                        }
+
+                        return false;
+                    },
+                    .checked => {
+                        if (!n.isElement()) return false;
+
+                        const ntag = try n.tag();
+
+                        if (std.ascii.eqlIgnoreCase("intput", ntag)) {
+                            const ntype = try n.attr("type");
+                            if (ntype == null) return false;
+
+                            if (std.mem.eql(u8, ntype.?, "checkbox") or
+                                std.mem.eql(u8, ntype.?, "radio"))
+                            {
+                                return try n.attr("checked") != null;
+                            }
+
+                            return false;
+                        }
+                        if (std.ascii.eqlIgnoreCase("option", ntag)) {
+                            return try n.attr("selected") != null;
+                        }
+
+                        return false;
+                    },
+                    .visited => return false,
+                    .hover => return false,
+                    .active => return false,
+                    .focus => return false,
+                    // TODO implement using the url fragment.
+                    // see https://developer.mozilla.org/en-US/docs/Web/CSS/:target
+                    .target => return false,
+                    // visible always returns true.
+                    .visible => return true,
+
+                    // all others pseudo class are handled by specialized
+                    // pseudo_class_X selectors.
+                    else => return Error.UnsupportedPseudoClass,
+                };
+            },
+            .pseudo_class_only_child => |v| onlyChildMatch(v, n),
+            .pseudo_class_lang => |v| langMatch(v, n),
+
+            // pseudo elements doesn't make sense in the matching process.
+            // > A CSS pseudo-element is a keyword added to a selector that
+            // > lets you style a specific part of the selected element(s).
+            // https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-elements
+            .pseudo_element => return Error.UnsupportedPseudoElement,
+        };
+    }
+
+    fn hasLegendInPreviousSiblings(n: anytype) anyerror!bool {
+        var c = try n.prevSibling();
+        while (c != null) {
+            const ctag = try c.?.tag();
+            if (std.ascii.eqlIgnoreCase("legend", ctag)) return true;
+            c = try c.?.prevSibling();
+        }
+        return false;
+    }
+
+    fn inDisabledFieldset(n: anytype) anyerror!bool {
+        const p = try n.parent();
+        if (p == null) return false;
+
+        const ntag = try n.tag();
+        const ptag = try p.?.tag();
+
+        if (std.ascii.eqlIgnoreCase("fieldset", ptag) and
+            try p.?.attr("disabled") != null and
+            (!std.ascii.eqlIgnoreCase("legend", ntag) or try hasLegendInPreviousSiblings(n)))
+        {
+            return true;
+        }
+
+        // TODO should we handle legend like cascadia does?
+        // The implemention below looks suspicious, I didn't find a test case
+        // in cascadia and I didn't find the reference about legend in the
+        // specs. For now I do prefer ignoring this part.
+        //
+        // ```
+        // (n.DataAtom != atom.Legend || hasLegendInPreviousSiblings(n)) {
+        // ```
+        // https://github.com/andybalholm/cascadia/blob/master/pseudo_classes.go#L434
+
+        return try inDisabledFieldset(p.?);
+    }
+
+    fn langMatch(lang: []const u8, n: anytype) anyerror!bool {
+        if (try n.attr("lang")) |own| {
+            if (std.mem.eql(u8, own, lang)) return true;
+
+            // check if the lang attr starts with lang+'-'
+            if (std.mem.startsWith(u8, own, lang)) {
+                if (own.len > lang.len and own[lang.len] == '-') return true;
+            }
+        }
+
+        // if the tag doesn't match, try the parent.
+        const p = try n.parent();
+        if (p == null) return false;
+
+        return langMatch(lang, p.?);
+    }
+
+    // onlyChildMatch implements :only-child
+    //  If `ofType` is true, it implements :only-of-type instead.
+    fn onlyChildMatch(of_type: bool, n: anytype) anyerror!bool {
+        if (!n.isElement()) return false;
+
+        const p = try n.parent();
+        if (p == null) return false;
+
+        const ntag = try n.tag();
+
+        var count: usize = 0;
+        var c = try p.?.firstChild();
+        // loop hover all n siblings.
+        while (c != null) {
+            // ignore non elements or others tags if of-type is true.
+            if (!c.?.isElement() or (of_type and !std.mem.eql(u8, ntag, try c.?.tag()))) {
+                c = try c.?.nextSibling();
+                continue;
+            }
+
+            count += 1;
+            if (count > 1) return false;
+
+            c = try c.?.nextSibling();
+        }
+
+        return count == 1;
+    }
+
+    // simpleNthLastChildMatch implements :nth-last-child(b).
+    // If ofType is true, implements :nth-last-of-type instead.
+    fn simpleNthLastChildMatch(b: isize, of_type: bool, n: anytype) anyerror!bool {
+        if (!n.isElement()) return false;
+
+        const p = try n.parent();
+        if (p == null) return false;
+
+        const ntag = try n.tag();
+
+        var count: isize = 0;
+        var c = try p.?.lastChild();
+        // loop hover all n siblings.
+        while (c != null) {
+            // ignore non elements or others tags if of-type is true.
+            if (!c.?.isElement() or (of_type and !std.mem.eql(u8, ntag, try c.?.tag()))) {
+                c = try c.?.prevSibling();
+                continue;
+            }
+
+            count += 1;
+
+            if (n.eql(c.?)) return count == b;
+            if (count >= b) return false;
+
+            c = try c.?.prevSibling();
+        }
+
+        return false;
+    }
+
+    // simpleNthChildMatch implements :nth-child(b).
+    // If ofType is true, implements :nth-of-type instead.
+    fn simpleNthChildMatch(b: isize, of_type: bool, n: anytype) anyerror!bool {
+        if (!n.isElement()) return false;
+
+        const p = try n.parent();
+        if (p == null) return false;
+
+        const ntag = try n.tag();
+
+        var count: isize = 0;
+        var c = try p.?.firstChild();
+        // loop hover all n siblings.
+        while (c != null) {
+            // ignore non elements or others tags if of-type is true.
+            if (!c.?.isElement() or (of_type and !std.mem.eql(u8, ntag, try c.?.tag()))) {
+                c = try c.?.nextSibling();
+                continue;
+            }
+
+            count += 1;
+
+            if (n.eql(c.?)) return count == b;
+            if (count >= b) return false;
+
+            c = try c.?.nextSibling();
+        }
+
+        return false;
+    }
+
+    // nthChildMatch implements :nth-child(an+b).
+    // If last is true, implements :nth-last-child instead.
+    // If ofType is true, implements :nth-of-type instead.
+    fn nthChildMatch(a: isize, b: isize, last: bool, of_type: bool, n: anytype) anyerror!bool {
+        if (!n.isElement()) return false;
+
+        const p = try n.parent();
+        if (p == null) return false;
+
+        const ntag = try n.tag();
+
+        var i: isize = -1;
+        var count: isize = 0;
+        var c = try p.?.firstChild();
+        // loop hover all n siblings.
+        while (c != null) {
+            // ignore non elements or others tags if of-type is true.
+            if (!c.?.isElement() or (of_type and !std.mem.eql(u8, ntag, try c.?.tag()))) {
+                c = try c.?.nextSibling();
+                continue;
+            }
+            count += 1;
+
+            if (n.eql(c.?)) {
+                i = count;
+                if (!last) break;
+            }
+
+            c = try c.?.nextSibling();
+        }
+
+        if (i == -1) return false;
+
+        if (last) i = count - i + 1;
+
+        i -= b;
+        if (a == 0) return i == 0;
+        return @mod(i, a) == 0 and @divTrunc(i, a) >= 0;
+    }
+
+    fn hasDescendantMatch(s: *const Selector, n: anytype) anyerror!bool {
+        var c = try n.firstChild();
+        while (c != null) {
+            if (try s.match(c.?)) return true;
+            if (c.?.isElement() and try hasDescendantMatch(s, c.?)) return true;
+            c = try c.?.nextSibling();
+        }
+
+        return false;
+    }
+
+    fn hasChildMatch(s: *const Selector, n: anytype) anyerror!bool {
+        var c = try n.firstChild();
+        while (c != null) {
+            if (try s.match(c.?)) return true;
+            c = try c.?.nextSibling();
+        }
+
+        return false;
+    }
+
+    pub fn deinit(sel: Selector, alloc: std.mem.Allocator) void {
+        switch (sel) {
+            .group => |v| {
+                for (v) |vv| vv.deinit(alloc);
+                alloc.free(v);
+            },
+            .compound => |v| {
+                for (v.selectors) |vv| vv.deinit(alloc);
+                alloc.free(v.selectors);
+            },
+            .tag, .id, .class, .pseudo_class_lang => |v| alloc.free(v),
+            .attribute => |att| {
+                alloc.free(att.key);
+                if (att.val) |v| alloc.free(v);
+                if (att.regexp) |v| alloc.free(v);
+            },
+            .combined => |c| {
+                c.first.deinit(alloc);
+                alloc.destroy(c.first);
+                c.second.deinit(alloc);
+                alloc.destroy(c.second);
+            },
+            .pseudo_class_relative => |v| {
+                v.match.deinit(alloc);
+                alloc.destroy(v.match);
+            },
+            .pseudo_class_contains => |v| alloc.free(v.val),
+            .pseudo_class_regexp => |v| alloc.free(v.regexp),
+            .pseudo_class, .pseudo_element, .never_match => {},
+            .pseudo_class_nth, .pseudo_class_only_child => {},
+        }
+    }
+};
--- a/src/browser/cssom/css_parser.zig
+++ b/src/browser/cssom/css_parser.zig
@@ -0,0 +1,291 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const CSSConstants = struct {
+    const IMPORTANT = "!important";
+    const URL_PREFIX = "url(";
+};
+
+pub const CSSParserState = enum {
+    seek_name,
+    in_name,
+    seek_colon,
+    seek_value,
+    in_value,
+    in_quoted_value,
+    in_single_quoted_value,
+    in_url,
+    in_important,
+};
+
+pub const CSSDeclaration = struct {
+    name: []const u8,
+    value: []const u8,
+    is_important: bool,
+};
+
+pub const CSSParser = struct {
+    state: CSSParserState,
+    name_start: usize,
+    name_end: usize,
+    value_start: usize,
+    position: usize,
+    paren_depth: usize,
+    escape_next: bool,
+
+    pub fn init() CSSParser {
+        return .{
+            .state = .seek_name,
+            .name_start = 0,
+            .name_end = 0,
+            .value_start = 0,
+            .position = 0,
+            .paren_depth = 0,
+            .escape_next = false,
+        };
+    }
+
+    pub fn parseDeclarations(arena: Allocator, text: []const u8) ![]CSSDeclaration {
+        var parser = init();
+        var declarations: std.ArrayListUnmanaged(CSSDeclaration) = .empty;
+
+        while (parser.position < text.len) {
+            const c = text[parser.position];
+
+            switch (parser.state) {
+                .seek_name => {
+                    if (!std.ascii.isWhitespace(c)) {
+                        parser.name_start = parser.position;
+                        parser.state = .in_name;
+                        continue;
+                    }
+                },
+                .in_name => {
+                    if (c == ':') {
+                        parser.name_end = parser.position;
+                        parser.state = .seek_value;
+                    } else if (std.ascii.isWhitespace(c)) {
+                        parser.name_end = parser.position;
+                        parser.state = .seek_colon;
+                    }
+                },
+                .seek_colon => {
+                    if (c == ':') {
+                        parser.state = .seek_value;
+                    } else if (!std.ascii.isWhitespace(c)) {
+                        parser.state = .seek_name;
+                        continue;
+                    }
+                },
+                .seek_value => {
+                    if (!std.ascii.isWhitespace(c)) {
+                        parser.value_start = parser.position;
+                        if (c == '"') {
+                            parser.state = .in_quoted_value;
+                        } else if (c == '\'') {
+                            parser.state = .in_single_quoted_value;
+                        } else if (c == 'u' and parser.position + CSSConstants.URL_PREFIX.len <= text.len and std.mem.startsWith(u8, text[parser.position..], CSSConstants.URL_PREFIX)) {
+                            parser.state = .in_url;
+                            parser.paren_depth = 1;
+                            parser.position += 3;
+                        } else {
+                            parser.state = .in_value;
+                            continue;
+                        }
+                    }
+                },
+                .in_value => {
+                    if (parser.escape_next) {
+                        parser.escape_next = false;
+                    } else if (c == '\\') {
+                        parser.escape_next = true;
+                    } else if (c == '(') {
+                        parser.paren_depth += 1;
+                    } else if (c == ')' and parser.paren_depth > 0) {
+                        parser.paren_depth -= 1;
+                    } else if (c == ';' and parser.paren_depth == 0) {
+                        try parser.finishDeclaration(arena, &declarations, text);
+                        parser.state = .seek_name;
+                    }
+                },
+                .in_quoted_value => {
+                    if (parser.escape_next) {
+                        parser.escape_next = false;
+                    } else if (c == '\\') {
+                        parser.escape_next = true;
+                    } else if (c == '"') {
+                        parser.state = .in_value;
+                    }
+                },
+                .in_single_quoted_value => {
+                    if (parser.escape_next) {
+                        parser.escape_next = false;
+                    } else if (c == '\\') {
+                        parser.escape_next = true;
+                    } else if (c == '\'') {
+                        parser.state = .in_value;
+                    }
+                },
+                .in_url => {
+                    if (parser.escape_next) {
+                        parser.escape_next = false;
+                    } else if (c == '\\') {
+                        parser.escape_next = true;
+                    } else if (c == '(') {
+                        parser.paren_depth += 1;
+                    } else if (c == ')') {
+                        parser.paren_depth -= 1;
+                        if (parser.paren_depth == 0) {
+                            parser.state = .in_value;
+                        }
+                    }
+                },
+                .in_important => {},
+            }
+
+            parser.position += 1;
+        }
+
+        try parser.finalize(arena, &declarations, text);
+
+        return declarations.items;
+    }
+
+    fn finishDeclaration(self: *CSSParser, arena: Allocator, declarations: *std.ArrayListUnmanaged(CSSDeclaration), text: []const u8) !void {
+        const name = std.mem.trim(u8, text[self.name_start..self.name_end], &std.ascii.whitespace);
+        if (name.len == 0) return;
+
+        const raw_value = text[self.value_start..self.position];
+        const value = std.mem.trim(u8, raw_value, &std.ascii.whitespace);
+
+        var final_value = value;
+        var is_important = false;
+
+        if (std.mem.endsWith(u8, value, CSSConstants.IMPORTANT)) {
+            is_important = true;
+            final_value = std.mem.trimRight(u8, value[0 .. value.len - CSSConstants.IMPORTANT.len], &std.ascii.whitespace);
+        }
+
+        try declarations.append(arena, .{
+            .name = name,
+            .value = final_value,
+            .is_important = is_important,
+        });
+    }
+
+    fn finalize(self: *CSSParser, arena: Allocator, declarations: *std.ArrayListUnmanaged(CSSDeclaration), text: []const u8) !void {
+        if (self.state != .in_value) {
+            return;
+        }
+        return self.finishDeclaration(arena, declarations, text);
+    }
+};
+
+const testing = @import("../../testing.zig");
+
+test "CSSParser - Simple property" {
+    defer testing.reset();
+
+    const text = "color: red;";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expectEqual(1, declarations.len);
+    try testing.expectEqual("color", declarations[0].name);
+    try testing.expectEqual("red", declarations[0].value);
+    try testing.expectEqual(false, declarations[0].is_important);
+}
+
+test "CSSParser - Property with !important" {
+    defer testing.reset();
+    const text = "margin: 10px !important;";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expectEqual(1, declarations.len);
+    try testing.expectEqual("margin", declarations[0].name);
+    try testing.expectEqual("10px", declarations[0].value);
+    try testing.expectEqual(true, declarations[0].is_important);
+}
+
+test "CSSParser - Multiple properties" {
+    defer testing.reset();
+    const text = "color: red; font-size: 12px; margin: 5px !important;";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expect(declarations.len == 3);
+
+    try testing.expectEqual("color", declarations[0].name);
+    try testing.expectEqual("red", declarations[0].value);
+    try testing.expectEqual(false, declarations[0].is_important);
+
+    try testing.expectEqual("font-size", declarations[1].name);
+    try testing.expectEqual("12px", declarations[1].value);
+    try testing.expectEqual(false, declarations[1].is_important);
+
+    try testing.expectEqual("margin", declarations[2].name);
+    try testing.expectEqual("5px", declarations[2].value);
+    try testing.expectEqual(true, declarations[2].is_important);
+}
+
+test "CSSParser - Quoted value with semicolon" {
+    defer testing.reset();
+    const text = "content: \"Hello; world!\";";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expectEqual(1, declarations.len);
+    try testing.expectEqual("content", declarations[0].name);
+    try testing.expectEqual("\"Hello; world!\"", declarations[0].value);
+    try testing.expectEqual(false, declarations[0].is_important);
+}
+
+test "CSSParser - URL value" {
+    defer testing.reset();
+    const text = "background-image: url(\"test.png\");";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expectEqual(1, declarations.len);
+    try testing.expectEqual("background-image", declarations[0].name);
+    try testing.expectEqual("url(\"test.png\")", declarations[0].value);
+    try testing.expectEqual(false, declarations[0].is_important);
+}
+
+test "CSSParser - Whitespace handling" {
+    defer testing.reset();
+    const text = "  color  :  purple  ;  margin  :  10px  ;  ";
+    const allocator = testing.arena_allocator;
+
+    const declarations = try CSSParser.parseDeclarations(allocator, text);
+
+    try testing.expectEqual(2, declarations.len);
+    try testing.expectEqual("color", declarations[0].name);
+    try testing.expectEqual("purple", declarations[0].value);
+    try testing.expectEqual("margin", declarations[1].name);
+    try testing.expectEqual("10px", declarations[1].value);
+}
--- a/src/browser/cssom/css_rule.zig
+++ b/src/browser/cssom/css_rule.zig
@@ -0,0 +1,42 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const CSSStyleSheet = @import("css_stylesheet.zig").CSSStyleSheet;
+
+pub const Interfaces = .{
+    CSSRule,
+    CSSImportRule,
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/CSSRule
+pub const CSSRule = struct {
+    css_text: []const u8,
+    parent_rule: ?*CSSRule = null,
+    parent_stylesheet: ?*CSSStyleSheet = null,
+};
+
+pub const CSSImportRule = struct {
+    pub const prototype = *CSSRule;
+    href: []const u8,
+    layer_name: ?[]const u8,
+    media: void,
+    style_sheet: CSSStyleSheet,
+    supports_text: ?[]const u8,
+};
--- a/src/browser/cssom/css_rule_list.zig
+++ b/src/browser/cssom/css_rule_list.zig
@@ -0,0 +1,60 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const StyleSheet = @import("stylesheet.zig").StyleSheet;
+const CSSRule = @import("css_rule.zig").CSSRule;
+const CSSImportRule = @import("css_rule.zig").CSSImportRule;
+
+pub const CSSRuleList = struct {
+    list: std.ArrayListUnmanaged([]const u8),
+
+    pub fn constructor() CSSRuleList {
+        return .{ .list = .empty };
+    }
+
+    pub fn _item(self: *CSSRuleList, _index: u32) ?CSSRule {
+        const index: usize = @intCast(_index);
+
+        if (index > self.list.items.len) {
+            return null;
+        }
+
+        // todo: for now, just return null.
+        // this depends on properly parsing CSSRule
+        return null;
+    }
+
+    pub fn get_length(self: *CSSRuleList) u32 {
+        return @intCast(self.list.items.len);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.CSS.CSSRuleList" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let list = new CSSRuleList()", "undefined" },
+        .{ "list instanceof CSSRuleList", "true" },
+        .{ "list.length", "0" },
+        .{ "list.item(0)", "null" },
+    }, .{});
+}
--- a/src/browser/cssom/css_style_declaration.zig
+++ b/src/browser/cssom/css_style_declaration.zig
@@ -0,0 +1,241 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const CSSParser = @import("./css_parser.zig").CSSParser;
+const CSSValueAnalyzer = @import("./css_value_analyzer.zig").CSSValueAnalyzer;
+const CSSRule = @import("css_rule.zig").CSSRule;
+const Page = @import("../page.zig").Page;
+
+pub const CSSStyleDeclaration = struct {
+    store: std.StringHashMapUnmanaged(Property),
+    order: std.ArrayListUnmanaged([]const u8),
+
+    pub const empty: CSSStyleDeclaration = .{
+        .store = .empty,
+        .order = .empty,
+    };
+
+    const Property = struct {
+        value: []const u8,
+        priority: bool,
+    };
+
+    pub fn get_cssFloat(self: *const CSSStyleDeclaration) []const u8 {
+        return self._getPropertyValue("float");
+    }
+
+    pub fn set_cssFloat(self: *CSSStyleDeclaration, value: ?[]const u8, page: *Page) !void {
+        const final_value = value orelse "";
+        return self._setProperty("float", final_value, null, page);
+    }
+
+    pub fn get_cssText(self: *const CSSStyleDeclaration, page: *Page) ![]const u8 {
+        var buffer: std.ArrayListUnmanaged(u8) = .empty;
+        const writer = buffer.writer(page.call_arena);
+        for (self.order.items) |name| {
+            const prop = self.store.get(name).?;
+            const escaped = try CSSValueAnalyzer.escapeCSSValue(page.call_arena, prop.value);
+            try writer.print("{s}: {s}", .{ name, escaped });
+            if (prop.priority) try writer.writeAll(" !important");
+            try writer.writeAll("; ");
+        }
+        return buffer.items;
+    }
+
+    // TODO Propagate also upward to parent node
+    pub fn set_cssText(self: *CSSStyleDeclaration, text: []const u8, page: *Page) !void {
+        self.store.clearRetainingCapacity();
+        self.order.clearRetainingCapacity();
+
+        // call_arena is safe here, because _setProperty will dupe the name
+        // using the page's longer-living arena.
+        const declarations = try CSSParser.parseDeclarations(page.call_arena, text);
+
+        for (declarations) |decl| {
+            if (!CSSValueAnalyzer.isValidPropertyName(decl.name)) continue;
+            const priority: ?[]const u8 = if (decl.is_important) "important" else null;
+            try self._setProperty(decl.name, decl.value, priority, page);
+        }
+    }
+
+    pub fn get_length(self: *const CSSStyleDeclaration) usize {
+        return self.order.items.len;
+    }
+
+    pub fn get_parentRule(_: *const CSSStyleDeclaration) ?CSSRule {
+        return null;
+    }
+
+    pub fn _getPropertyPriority(self: *const CSSStyleDeclaration, name: []const u8) []const u8 {
+        return if (self.store.get(name)) |prop| (if (prop.priority) "important" else "") else "";
+    }
+
+    // TODO should handle properly shorthand properties and canonical forms
+    pub fn _getPropertyValue(self: *const CSSStyleDeclaration, name: []const u8) []const u8 {
+        if (self.store.get(name)) |prop| {
+            return prop.value;
+        }
+
+        // default to everything being visible (unless it's been explicitly set)
+        if (std.mem.eql(u8, name, "visibility")) {
+            return "visible";
+        }
+
+        return "";
+    }
+
+    pub fn _item(self: *const CSSStyleDeclaration, index: usize) []const u8 {
+        return if (index < self.order.items.len) self.order.items[index] else "";
+    }
+
+    pub fn _removeProperty(self: *CSSStyleDeclaration, name: []const u8) ![]const u8 {
+        const prop = self.store.fetchRemove(name) orelse return "";
+        for (self.order.items, 0..) |item, i| {
+            if (std.mem.eql(u8, item, name)) {
+                _ = self.order.orderedRemove(i);
+                break;
+            }
+        }
+        // safe to return, since it's in our page.arena
+        return prop.value.value;
+    }
+
+    pub fn _setProperty(self: *CSSStyleDeclaration, name: []const u8, value: []const u8, priority: ?[]const u8, page: *Page) !void {
+        const owned_value = try page.arena.dupe(u8, value);
+        const is_important = priority != null and std.ascii.eqlIgnoreCase(priority.?, "important");
+
+        const gop = try self.store.getOrPut(page.arena, name);
+        if (!gop.found_existing) {
+            const owned_name = try page.arena.dupe(u8, name);
+            gop.key_ptr.* = owned_name;
+            try self.order.append(page.arena, owned_name);
+        }
+
+        gop.value_ptr.* = .{ .value = owned_value, .priority = is_important };
+    }
+
+    pub fn named_get(self: *const CSSStyleDeclaration, name: []const u8, _: *bool) []const u8 {
+        return self._getPropertyValue(name);
+    }
+};
+
+const testing = @import("../../testing.zig");
+
+test "CSSOM.CSSStyleDeclaration" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let style = document.getElementById('content').style", "undefined" },
+        .{ "style.cssText = 'color: red; font-size: 12px; margin: 5px !important;'", "color: red; font-size: 12px; margin: 5px !important;" },
+        .{ "style.length", "3" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.getPropertyValue('color')", "red" },
+        .{ "style.getPropertyValue('font-size')", "12px" },
+        .{ "style.getPropertyValue('unknown-property')", "" },
+
+        .{ "style.getPropertyPriority('margin')", "important" },
+        .{ "style.getPropertyPriority('color')", "" },
+        .{ "style.getPropertyPriority('unknown-property')", "" },
+
+        .{ "style.item(0)", "color" },
+        .{ "style.item(1)", "font-size" },
+        .{ "style.item(2)", "margin" },
+        .{ "style.item(3)", "" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.setProperty('background-color', 'blue')", "undefined" },
+        .{ "style.getPropertyValue('background-color')", "blue" },
+        .{ "style.length", "4" },
+
+        .{ "style.setProperty('color', 'green')", "undefined" },
+        .{ "style.getPropertyValue('color')", "green" },
+        .{ "style.length", "4" },
+        .{ "style.color", "green" },
+
+        .{ "style.setProperty('padding', '10px', 'important')", "undefined" },
+        .{ "style.getPropertyValue('padding')", "10px" },
+        .{ "style.getPropertyPriority('padding')", "important" },
+
+        .{ "style.setProperty('border', '1px solid black', 'IMPORTANT')", "undefined" },
+        .{ "style.getPropertyPriority('border')", "important" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.removeProperty('color')", "green" },
+        .{ "style.getPropertyValue('color')", "" },
+        .{ "style.length", "5" },
+
+        .{ "style.removeProperty('unknown-property')", "" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.cssText.includes('font-size: 12px;')", "true" },
+        .{ "style.cssText.includes('margin: 5px !important;')", "true" },
+        .{ "style.cssText.includes('padding: 10px !important;')", "true" },
+        .{ "style.cssText.includes('border: 1px solid black !important;')", "true" },
+
+        .{ "style.cssText = 'color: purple; text-align: center;'", "color: purple; text-align: center;" },
+        .{ "style.length", "2" },
+        .{ "style.getPropertyValue('color')", "purple" },
+        .{ "style.getPropertyValue('text-align')", "center" },
+        .{ "style.getPropertyValue('font-size')", "" },
+
+        .{ "style.setProperty('cont', 'Hello; world!')", "undefined" },
+        .{ "style.getPropertyValue('cont')", "Hello; world!" },
+
+        .{ "style.cssText = 'content: \"Hello; world!\"; background-image: url(\"test.png\");'", "content: \"Hello; world!\"; background-image: url(\"test.png\");" },
+        .{ "style.getPropertyValue('content')", "\"Hello; world!\"" },
+        .{ "style.getPropertyValue('background-image')", "url(\"test.png\")" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.cssFloat", "" },
+        .{ "style.cssFloat = 'left'", "left" },
+        .{ "style.cssFloat", "left" },
+        .{ "style.getPropertyValue('float')", "left" },
+
+        .{ "style.cssFloat = 'right'", "right" },
+        .{ "style.cssFloat", "right" },
+
+        .{ "style.cssFloat = null", "null" },
+        .{ "style.cssFloat", "" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.setProperty('display', '')", "undefined" },
+        .{ "style.getPropertyValue('display')", "" },
+
+        .{ "style.cssText = '  color  :  purple  ;  margin  :  10px  ;  '", "  color  :  purple  ;  margin  :  10px  ;  " },
+        .{ "style.getPropertyValue('color')", "purple" },
+        .{ "style.getPropertyValue('margin')", "10px" },
+
+        .{ "style.setProperty('border-bottom-left-radius', '5px')", "undefined" },
+        .{ "style.getPropertyValue('border-bottom-left-radius')", "5px" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "style.visibility", "visible" },
+        .{ "style.getPropertyValue('visibility')", "visible" },
+    }, .{});
+}
--- a/src/browser/cssom/css_stylesheet.zig
+++ b/src/browser/cssom/css_stylesheet.zig
@@ -0,0 +1,91 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Page = @import("../page.zig").Page;
+const StyleSheet = @import("stylesheet.zig").StyleSheet;
+
+const CSSRuleList = @import("css_rule_list.zig").CSSRuleList;
+const CSSImportRule = @import("css_rule.zig").CSSImportRule;
+
+pub const CSSStyleSheet = struct {
+    pub const prototype = *StyleSheet;
+
+    proto: StyleSheet,
+    css_rules: CSSRuleList,
+    owner_rule: ?*CSSImportRule,
+
+    const CSSStyleSheetOpts = struct {
+        base_url: ?[]const u8 = null,
+        // TODO: Suupport media
+        disabled: bool = false,
+    };
+
+    pub fn constructor(_opts: ?CSSStyleSheetOpts) !CSSStyleSheet {
+        const opts = _opts orelse CSSStyleSheetOpts{};
+        return .{
+            .proto = StyleSheet{ .disabled = opts.disabled },
+            .css_rules = .constructor(),
+            .owner_rule = null,
+        };
+    }
+
+    pub fn get_ownerRule(_: *CSSStyleSheet) ?*CSSImportRule {
+        return null;
+    }
+
+    pub fn get_cssRules(self: *CSSStyleSheet) *CSSRuleList {
+        return &self.css_rules;
+    }
+
+    pub fn _insertRule(self: *CSSStyleSheet, rule: []const u8, _index: ?usize, page: *Page) !usize {
+        const index = _index orelse 0;
+        if (index > self.css_rules.list.items.len) {
+            return error.IndexSize;
+        }
+
+        const arena = page.arena;
+        try self.css_rules.list.insert(arena, index, try arena.dupe(u8, rule));
+        return index;
+    }
+
+    pub fn _deleteRule(self: *CSSStyleSheet, index: usize) !void {
+        if (index > self.css_rules.list.items.len) {
+            return error.IndexSize;
+        }
+
+        _ = self.css_rules.list.orderedRemove(index);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.CSS.StyleSheet" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let css = new CSSStyleSheet()", "undefined" },
+        .{ "css instanceof CSSStyleSheet", "true" },
+        .{ "css.cssRules.length", "0" },
+        .{ "css.ownerRule", "null" },
+        .{ "let index1 = css.insertRule('body { color: red; }', 0)", "undefined" },
+        .{ "index1", "0" },
+        .{ "css.cssRules.length", "1" },
+    }, .{});
+}
--- a/src/browser/cssom/css_value_analyzer.zig
+++ b/src/browser/cssom/css_value_analyzer.zig
@@ -0,0 +1,811 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+pub const CSSValueAnalyzer = struct {
+    pub fn isNumericWithUnit(value: []const u8) bool {
+        if (value.len == 0) return false;
+
+        if (!std.ascii.isDigit(value[0]) and
+            value[0] != '+' and value[0] != '-' and value[0] != '.')
+        {
+            return false;
+        }
+
+        var i: usize = 0;
+        var has_digit = false;
+        var decimal_point = false;
+
+        while (i < value.len) : (i += 1) {
+            const c = value[i];
+            if (std.ascii.isDigit(c)) {
+                has_digit = true;
+            } else if (c == '.' and !decimal_point) {
+                decimal_point = true;
+            } else if ((c == 'e' or c == 'E') and has_digit) {
+                if (i + 1 >= value.len) return false;
+                if (value[i + 1] != '+' and value[i + 1] != '-' and !std.ascii.isDigit(value[i + 1])) break;
+                i += 1;
+                if (value[i] == '+' or value[i] == '-') {
+                    i += 1;
+                }
+                var has_exp_digits = false;
+                while (i < value.len and std.ascii.isDigit(value[i])) : (i += 1) {
+                    has_exp_digits = true;
+                }
+                if (!has_exp_digits) return false;
+                break;
+            } else if (c != '-' and c != '+') {
+                break;
+            }
+        }
+
+        if (!has_digit) return false;
+
+        if (i == value.len) return true;
+
+        const unit = value[i..];
+        return CSSKeywords.isValidUnit(unit);
+    }
+
+    pub fn isHexColor(value: []const u8) bool {
+        if (!std.mem.startsWith(u8, value, "#")) return false;
+
+        const hex_part = value[1..];
+        if (hex_part.len != 3 and hex_part.len != 6 and hex_part.len != 8) return false;
+
+        for (hex_part) |c| {
+            if (!std.ascii.isHex(c)) return false;
+        }
+
+        return true;
+    }
+
+    pub fn isMultiValueProperty(value: []const u8) bool {
+        var parts = std.mem.splitAny(u8, value, " ");
+        var multi_value_parts: usize = 0;
+        var all_parts_valid = true;
+
+        while (parts.next()) |part| {
+            if (part.len == 0) continue;
+            multi_value_parts += 1;
+
+            const is_numeric = isNumericWithUnit(part);
+            const is_hex_color = isHexColor(part);
+            const is_known_keyword = CSSKeywords.isKnownKeyword(part);
+            const is_function = CSSKeywords.startsWithFunction(part);
+
+            if (!is_numeric and !is_hex_color and !is_known_keyword and !is_function) {
+                all_parts_valid = false;
+                break;
+            }
+        }
+
+        return multi_value_parts >= 2 and all_parts_valid;
+    }
+
+    pub fn isAlreadyQuoted(value: []const u8) bool {
+        return value.len >= 2 and ((value[0] == '"' and value[value.len - 1] == '"') or
+            (value[0] == '\'' and value[value.len - 1] == '\''));
+    }
+
+    pub fn isValidPropertyName(name: []const u8) bool {
+        if (name.len == 0) return false;
+
+        if (std.mem.startsWith(u8, name, "--")) {
+            if (name.len == 2) return false;
+            for (name[2..]) |c| {
+                if (!std.ascii.isAlphanumeric(c) and c != '-' and c != '_') {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        const first_char = name[0];
+        if (!std.ascii.isAlphabetic(first_char) and first_char != '-') {
+            return false;
+        }
+
+        if (first_char == '-') {
+            if (name.len < 2) return false;
+
+            if (!std.ascii.isAlphabetic(name[1])) {
+                return false;
+            }
+
+            for (name[2..]) |c| {
+                if (!std.ascii.isAlphanumeric(c) and c != '-') {
+                    return false;
+                }
+            }
+        } else {
+            for (name[1..]) |c| {
+                if (!std.ascii.isAlphanumeric(c) and c != '-') {
+                    return false;
+                }
+            }
+        }
+
+        return true;
+    }
+
+    pub fn extractImportant(value: []const u8) struct { value: []const u8, is_important: bool } {
+        const trimmed = std.mem.trim(u8, value, &std.ascii.whitespace);
+
+        if (std.mem.endsWith(u8, trimmed, "!important")) {
+            const clean_value = std.mem.trimRight(u8, trimmed[0 .. trimmed.len - 10], &std.ascii.whitespace);
+            return .{ .value = clean_value, .is_important = true };
+        }
+
+        return .{ .value = trimmed, .is_important = false };
+    }
+
+    pub fn needsQuotes(value: []const u8) bool {
+        if (value.len == 0) return true;
+        if (isAlreadyQuoted(value)) return false;
+
+        if (CSSKeywords.containsSpecialChar(value)) {
+            return true;
+        }
+
+        if (std.mem.indexOfScalar(u8, value, ' ') == null) {
+            return false;
+        }
+
+        const is_url = std.mem.startsWith(u8, value, "url(");
+        const is_function = CSSKeywords.startsWithFunction(value);
+
+        return !isMultiValueProperty(value) and
+            !is_url and
+            !is_function;
+    }
+
+    pub fn escapeCSSValue(arena: std.mem.Allocator, value: []const u8) ![]const u8 {
+        if (!needsQuotes(value)) {
+            return value;
+        }
+        var out: std.ArrayListUnmanaged(u8) = .empty;
+
+        // We'll need at least this much space, +2 for the quotes
+        try out.ensureTotalCapacity(arena, value.len + 2);
+        const writer = out.writer(arena);
+
+        try writer.writeByte('"');
+
+        for (value, 0..) |c, i| {
+            switch (c) {
+                '"' => try writer.writeAll("\\\""),
+                '\\' => try writer.writeAll("\\\\"),
+                '\n' => try writer.writeAll("\\A "),
+                '\r' => try writer.writeAll("\\D "),
+                '\t' => try writer.writeAll("\\9 "),
+                0...8, 11, 12, 14...31, 127 => {
+                    try writer.print("\\{x}", .{c});
+                    if (i + 1 < value.len and std.ascii.isHex(value[i + 1])) {
+                        try writer.writeByte(' ');
+                    }
+                },
+                else => try writer.writeByte(c),
+            }
+        }
+
+        try writer.writeByte('"');
+        return out.items;
+    }
+
+    pub fn isKnownKeyword(value: []const u8) bool {
+        return CSSKeywords.isKnownKeyword(value);
+    }
+
+    pub fn containsSpecialChar(value: []const u8) bool {
+        return CSSKeywords.containsSpecialChar(value);
+    }
+};
+
+const CSSKeywords = struct {
+    const border_styles = [_][]const u8{
+        "none", "solid", "dotted", "dashed", "double", "groove", "ridge", "inset", "outset",
+    };
+
+    const color_names = [_][]const u8{
+        "black",        "white",   "red", "green", "blue", "yellow", "purple", "gray", "transparent",
+        "currentColor", "inherit",
+    };
+
+    const position_keywords = [_][]const u8{
+        "auto", "center", "left", "right", "top", "bottom",
+    };
+
+    const background_repeat = [_][]const u8{
+        "repeat", "no-repeat", "repeat-x", "repeat-y", "space", "round",
+    };
+
+    const font_styles = [_][]const u8{
+        "normal", "italic", "oblique", "bold", "bolder", "lighter",
+    };
+
+    const font_sizes = [_][]const u8{
+        "xx-small", "x-small", "small", "medium", "large", "x-large", "xx-large",
+        "smaller",  "larger",
+    };
+
+    const font_families = [_][]const u8{
+        "serif", "sans-serif", "monospace", "cursive", "fantasy", "system-ui",
+    };
+
+    const css_global = [_][]const u8{
+        "initial", "inherit", "unset", "revert",
+    };
+
+    const display_values = [_][]const u8{
+        "block", "inline", "inline-block", "flex", "grid", "none",
+    };
+
+    const length_units = [_][]const u8{
+        "px", "em", "rem", "vw", "vh", "vmin", "vmax", "%", "pt", "pc", "in", "cm", "mm",
+        "ex", "ch", "fr",
+    };
+
+    const angle_units = [_][]const u8{
+        "deg", "rad", "grad", "turn",
+    };
+
+    const time_units = [_][]const u8{
+        "s", "ms",
+    };
+
+    const frequency_units = [_][]const u8{
+        "Hz", "kHz",
+    };
+
+    const resolution_units = [_][]const u8{
+        "dpi", "dpcm", "dppx",
+    };
+
+    const special_chars = [_]u8{
+        '"', '\'', ';', '{', '}', '\\', '<', '>', '/', '\n', '\t', '\r', '\x00', '\x7F',
+    };
+
+    const functions = [_][]const u8{
+        "rgb(",             "rgba(",            "hsl(",            "hsla(",      "url(",    "calc(",  "var(",  "attr(",
+        "linear-gradient(", "radial-gradient(", "conic-gradient(", "translate(", "rotate(", "scale(", "skew(", "matrix(",
+    };
+
+    pub fn isKnownKeyword(value: []const u8) bool {
+        const all_categories = [_][]const []const u8{
+            &border_styles,  &color_names, &position_keywords, &background_repeat,
+            &font_styles,    &font_sizes,  &font_families,     &css_global,
+            &display_values,
+        };
+
+        for (all_categories) |category| {
+            for (category) |keyword| {
+                if (std.ascii.eqlIgnoreCase(value, keyword)) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    pub fn containsSpecialChar(value: []const u8) bool {
+        for (value) |c| {
+            for (special_chars) |special| {
+                if (c == special) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    pub fn isValidUnit(unit: []const u8) bool {
+        const all_units = [_][]const []const u8{
+            &length_units, &angle_units, &time_units, &frequency_units, &resolution_units,
+        };
+
+        for (all_units) |category| {
+            for (category) |valid_unit| {
+                if (std.ascii.eqlIgnoreCase(unit, valid_unit)) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+
+    pub fn startsWithFunction(value: []const u8) bool {
+        const pos = std.mem.indexOfScalar(u8, value, '(') orelse return false;
+        if (pos == 0) return false;
+
+        if (std.mem.indexOfScalarPos(u8, value, pos, ')') == null) {
+            return false;
+        }
+        const function_name = value[0..pos];
+        return isValidFunctionName(function_name);
+    }
+
+    fn isValidFunctionName(name: []const u8) bool {
+        if (name.len == 0) return false;
+
+        const first = name[0];
+        if (!std.ascii.isAlphabetic(first) and first != '_' and first != '-') {
+            return false;
+        }
+
+        for (name[1..]) |c| {
+            if (!std.ascii.isAlphanumeric(c) and c != '_' and c != '-') {
+                return false;
+            }
+        }
+
+        return true;
+    }
+};
+
+const testing = @import("../../testing.zig");
+
+test "CSSValueAnalyzer: isNumericWithUnit - valid numbers with units" {
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("10px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("3.14em"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("-5rem"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("+12.5%"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("0vh"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit(".5vw"));
+}
+
+test "CSSValueAnalyzer: isNumericWithUnit - scientific notation" {
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("1e5px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("2.5E-3em"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("1e+2rem"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("-3.14e10px"));
+}
+
+test "CSSValueAnalyzer: isNumericWithUnit - edge cases and invalid inputs" {
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(""));
+
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("px"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("--px"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(".px"));
+
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("1e"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("1epx"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("1e+"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("1e+px"));
+
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("1.2.3px"));
+
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("10xyz"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("5invalid"));
+
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("10"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("3.14"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("-5"));
+}
+
+test "CSSValueAnalyzer: isHexColor - valid hex colors" {
+    try testing.expect(CSSValueAnalyzer.isHexColor("#000"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#fff"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#123456"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#abcdef"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#ABCDEF"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#12345678"));
+}
+
+test "CSSValueAnalyzer: isHexColor - invalid hex colors" {
+    try testing.expect(!CSSValueAnalyzer.isHexColor(""));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("000"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#00"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#0000"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#00000"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#0000000"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#000000000"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#gggggg"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#123xyz"));
+}
+
+test "CSSValueAnalyzer: isMultiValueProperty - valid multi-value properties" {
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("10px 20px"));
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("solid red"));
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("#fff black"));
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("1em 2em 3em 4em"));
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("rgb(255,0,0) solid"));
+}
+
+test "CSSValueAnalyzer: isMultiValueProperty - invalid multi-value properties" {
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty(""));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("10px"));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("invalid unknown"));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("10px invalid"));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("   "));
+}
+
+test "CSSValueAnalyzer: isAlreadyQuoted - various quoting scenarios" {
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("\"hello\""));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("'world'"));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("\"\""));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("''"));
+
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted(""));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("hello"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("\""));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("'"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("\"hello'"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("'hello\""));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("\"hello"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("hello\""));
+}
+
+test "CSSValueAnalyzer: isValidPropertyName - valid property names" {
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("color"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("background-color"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("-webkit-transform"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("font-size"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("margin-top"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("z-index"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("line-height"));
+}
+
+test "CSSValueAnalyzer: isValidPropertyName - invalid property names" {
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName(""));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("123color"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("color!"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("color space"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("@color"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("color.test"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("color_test"));
+}
+
+test "CSSValueAnalyzer: extractImportant - with and without !important" {
+    var result = CSSValueAnalyzer.extractImportant("red !important");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("red", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("blue");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("blue", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("  green  !important  ");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("green", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("!important");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("important");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("important", result.value);
+}
+
+test "CSSValueAnalyzer: needsQuotes - various scenarios" {
+    try testing.expect(CSSValueAnalyzer.needsQuotes(""));
+    try testing.expect(CSSValueAnalyzer.needsQuotes("hello world"));
+    try testing.expect(CSSValueAnalyzer.needsQuotes("test;"));
+    try testing.expect(CSSValueAnalyzer.needsQuotes("a{b}"));
+    try testing.expect(CSSValueAnalyzer.needsQuotes("test\"quote"));
+
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("\"already quoted\""));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("'already quoted'"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("url(image.png)"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("rgb(255, 0, 0)"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("10px 20px"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("simple"));
+}
+
+test "CSSValueAnalyzer: escapeCSSValue - escaping various characters" {
+    const allocator = testing.arena_allocator;
+
+    var result = try CSSValueAnalyzer.escapeCSSValue(allocator, "simple");
+    try testing.expectEqual("simple", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "\"already quoted\"");
+    try testing.expectEqual("\"already quoted\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\"quote");
+    try testing.expectEqual("\"test\\\"quote\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\nline");
+    try testing.expectEqual("\"test\\A line\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\\back");
+    try testing.expectEqual("\"test\\\\back\"", result);
+}
+
+test "CSSValueAnalyzer: CSSKeywords.isKnownKeyword - case sensitivity" {
+    try testing.expect(CSSKeywords.isKnownKeyword("red"));
+    try testing.expect(CSSKeywords.isKnownKeyword("solid"));
+    try testing.expect(CSSKeywords.isKnownKeyword("center"));
+    try testing.expect(CSSKeywords.isKnownKeyword("inherit"));
+
+    try testing.expect(CSSKeywords.isKnownKeyword("RED"));
+    try testing.expect(CSSKeywords.isKnownKeyword("Red"));
+    try testing.expect(CSSKeywords.isKnownKeyword("SOLID"));
+    try testing.expect(CSSKeywords.isKnownKeyword("Center"));
+
+    try testing.expect(!CSSKeywords.isKnownKeyword("invalid"));
+    try testing.expect(!CSSKeywords.isKnownKeyword("unknown"));
+    try testing.expect(!CSSKeywords.isKnownKeyword(""));
+}
+
+test "CSSValueAnalyzer: CSSKeywords.containsSpecialChar - various special characters" {
+    try testing.expect(CSSKeywords.containsSpecialChar("test\"quote"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test'quote"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test;end"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test{brace"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test}brace"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test\\back"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test<angle"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test>angle"));
+    try testing.expect(CSSKeywords.containsSpecialChar("test/slash"));
+
+    try testing.expect(!CSSKeywords.containsSpecialChar("normal-text"));
+    try testing.expect(!CSSKeywords.containsSpecialChar("text123"));
+    try testing.expect(!CSSKeywords.containsSpecialChar(""));
+}
+
+test "CSSValueAnalyzer: CSSKeywords.isValidUnit - various units" {
+    try testing.expect(CSSKeywords.isValidUnit("px"));
+    try testing.expect(CSSKeywords.isValidUnit("em"));
+    try testing.expect(CSSKeywords.isValidUnit("rem"));
+    try testing.expect(CSSKeywords.isValidUnit("%"));
+
+    try testing.expect(CSSKeywords.isValidUnit("deg"));
+    try testing.expect(CSSKeywords.isValidUnit("rad"));
+
+    try testing.expect(CSSKeywords.isValidUnit("s"));
+    try testing.expect(CSSKeywords.isValidUnit("ms"));
+
+    try testing.expect(CSSKeywords.isValidUnit("PX"));
+
+    try testing.expect(!CSSKeywords.isValidUnit("invalid"));
+    try testing.expect(!CSSKeywords.isValidUnit(""));
+}
+
+test "CSSValueAnalyzer: CSSKeywords.startsWithFunction - function detection" {
+    try testing.expect(CSSKeywords.startsWithFunction("rgb(255, 0, 0)"));
+    try testing.expect(CSSKeywords.startsWithFunction("rgba(255, 0, 0, 0.5)"));
+    try testing.expect(CSSKeywords.startsWithFunction("url(image.png)"));
+    try testing.expect(CSSKeywords.startsWithFunction("calc(100% - 20px)"));
+    try testing.expect(CSSKeywords.startsWithFunction("var(--custom-property)"));
+    try testing.expect(CSSKeywords.startsWithFunction("linear-gradient(to right, red, blue)"));
+
+    try testing.expect(CSSKeywords.startsWithFunction("custom-function(args)"));
+    try testing.expect(CSSKeywords.startsWithFunction("unknown(test)"));
+
+    try testing.expect(!CSSKeywords.startsWithFunction("not-a-function"));
+    try testing.expect(!CSSKeywords.startsWithFunction("missing-paren)"));
+    try testing.expect(!CSSKeywords.startsWithFunction("missing-close("));
+    try testing.expect(!CSSKeywords.startsWithFunction(""));
+    try testing.expect(!CSSKeywords.startsWithFunction("rgb"));
+}
+
+test "CSSValueAnalyzer: isNumericWithUnit - whitespace handling" {
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(" 10px"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("10 px"));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("10px "));
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(" 10 px "));
+}
+
+test "CSSValueAnalyzer: extractImportant - whitespace edge cases" {
+    var result = CSSValueAnalyzer.extractImportant("   ");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("\t\n\r !important\t\n");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("red\t!important");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("red", result.value);
+}
+
+test "CSSValueAnalyzer: isHexColor - mixed case handling" {
+    try testing.expect(CSSValueAnalyzer.isHexColor("#AbC"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#123aBc"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#FFffFF"));
+    try testing.expect(CSSValueAnalyzer.isHexColor("#000FFF"));
+}
+
+test "CSSValueAnalyzer: edge case - very long inputs" {
+    const long_valid = "a" ** 1000 ++ "px";
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(long_valid)); // not numeric
+
+    const long_property = "a-" ** 100 ++ "property";
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName(long_property));
+
+    const long_hex = "#" ++ "a" ** 20;
+    try testing.expect(!CSSValueAnalyzer.isHexColor(long_hex));
+}
+
+test "CSSValueAnalyzer: boundary conditions - numeric parsing" {
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("0px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("0.0px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit(".0px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("0.px"));
+
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("999999999px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("1.7976931348623157e+308px"));
+
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("0.000000001px"));
+    try testing.expect(CSSValueAnalyzer.isNumericWithUnit("1e-100px"));
+}
+
+test "CSSValueAnalyzer: extractImportant - malformed important declarations" {
+    var result = CSSValueAnalyzer.extractImportant("red ! important");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("red ! important", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("red !Important");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("red !Important", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("red !IMPORTANT");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("red !IMPORTANT", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("!importantred");
+    try testing.expect(!result.is_important);
+    try testing.expectEqual("!importantred", result.value);
+
+    result = CSSValueAnalyzer.extractImportant("red !important !important");
+    try testing.expect(result.is_important);
+    try testing.expectEqual("red !important", result.value);
+}
+
+test "CSSValueAnalyzer: isMultiValueProperty - complex spacing scenarios" {
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("10px    20px"));
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("solid     red"));
+
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("  10px 20px  "));
+
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("10px\t20px"));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("10px\n20px"));
+
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("10px   20px   30px"));
+}
+
+test "CSSValueAnalyzer: isAlreadyQuoted - edge cases with quotes" {
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("\"'hello'\""));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("'\"hello\"'"));
+
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("\"hello\\\"world\""));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("'hello\\'world'"));
+
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("\"hello"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("hello\""));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("'hello"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("hello'"));
+
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("\"a\""));
+    try testing.expect(CSSValueAnalyzer.isAlreadyQuoted("'b'"));
+}
+
+test "CSSValueAnalyzer: needsQuotes - function and URL edge cases" {
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("rgb(255, 0, 0)"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("calc(100% - 20px)"));
+
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("url(path with spaces.jpg)"));
+
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("linear-gradient(to right, red, blue)"));
+
+    try testing.expect(CSSValueAnalyzer.needsQuotes("rgb(255, 0, 0"));
+}
+
+test "CSSValueAnalyzer: escapeCSSValue - control characters and Unicode" {
+    const allocator = testing.arena_allocator;
+
+    var result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\ttab");
+    try testing.expectEqual("\"test\\9 tab\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\rreturn");
+    try testing.expectEqual("\"test\\D return\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\x00null");
+    try testing.expectEqual("\"test\\0null\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\x7Fdel");
+    try testing.expectEqual("\"test\\7f del\"", result);
+
+    result = try CSSValueAnalyzer.escapeCSSValue(allocator, "test\"quote\nline\\back");
+    try testing.expectEqual("\"test\\\"quote\\A line\\\\back\"", result);
+}
+
+test "CSSValueAnalyzer: isValidPropertyName - CSS custom properties and vendor prefixes" {
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("--custom-color"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("--my-variable"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("--123"));
+
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("-webkit-transform"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("-moz-border-radius"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("-ms-filter"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("-o-transition"));
+
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("-123invalid"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("--"));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName("-"));
+}
+
+test "CSSValueAnalyzer: startsWithFunction - case sensitivity and partial matches" {
+    try testing.expect(CSSKeywords.startsWithFunction("RGB(255, 0, 0)"));
+    try testing.expect(CSSKeywords.startsWithFunction("Rgb(255, 0, 0)"));
+    try testing.expect(CSSKeywords.startsWithFunction("URL(image.png)"));
+
+    try testing.expect(CSSKeywords.startsWithFunction("rg(something)"));
+    try testing.expect(CSSKeywords.startsWithFunction("ur(something)"));
+
+    try testing.expect(CSSKeywords.startsWithFunction("rgb(1,2,3)"));
+    try testing.expect(CSSKeywords.startsWithFunction("rgba(1,2,3,4)"));
+
+    try testing.expect(CSSKeywords.startsWithFunction("my-custom-function(args)"));
+    try testing.expect(CSSKeywords.startsWithFunction("function-with-dashes(test)"));
+
+    try testing.expect(!CSSKeywords.startsWithFunction("123function(test)"));
+}
+
+test "CSSValueAnalyzer: isHexColor - Unicode and invalid characters" {
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#ghijkl"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#12345g"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#xyz"));
+
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#АВС"));
+
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#1234567g"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("#g2345678"));
+}
+
+test "CSSValueAnalyzer: complex integration scenarios" {
+    const allocator = testing.arena_allocator;
+
+    try testing.expect(CSSValueAnalyzer.isMultiValueProperty("rgb(255,0,0) url(bg.jpg)"));
+
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("calc(100% - 20px)"));
+
+    const result = try CSSValueAnalyzer.escapeCSSValue(allocator, "fake(function with spaces");
+    try testing.expectEqual("\"fake(function with spaces\"", result);
+
+    const important_result = CSSValueAnalyzer.extractImportant("rgb(255,0,0) !important");
+    try testing.expect(important_result.is_important);
+    try testing.expectEqual("rgb(255,0,0)", important_result.value);
+}
+
+test "CSSValueAnalyzer: performance edge cases - empty and minimal inputs" {
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit(""));
+    try testing.expect(!CSSValueAnalyzer.isHexColor(""));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty(""));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted(""));
+    try testing.expect(!CSSValueAnalyzer.isValidPropertyName(""));
+    try testing.expect(CSSValueAnalyzer.needsQuotes(""));
+    try testing.expect(!CSSKeywords.isKnownKeyword(""));
+    try testing.expect(!CSSKeywords.containsSpecialChar(""));
+    try testing.expect(!CSSKeywords.isValidUnit(""));
+    try testing.expect(!CSSKeywords.startsWithFunction(""));
+
+    try testing.expect(!CSSValueAnalyzer.isNumericWithUnit("a"));
+    try testing.expect(!CSSValueAnalyzer.isHexColor("a"));
+    try testing.expect(!CSSValueAnalyzer.isMultiValueProperty("a"));
+    try testing.expect(!CSSValueAnalyzer.isAlreadyQuoted("a"));
+    try testing.expect(CSSValueAnalyzer.isValidPropertyName("a"));
+    try testing.expect(!CSSValueAnalyzer.needsQuotes("a"));
+}
--- a/src/browser/cssom/cssom.zig
+++ b/src/browser/cssom/cssom.zig
@@ -0,0 +1,30 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+pub const Stylesheet = @import("stylesheet.zig").StyleSheet;
+pub const CSSStylesheet = @import("css_stylesheet.zig").CSSStyleSheet;
+pub const CSSStyleDeclaration = @import("css_style_declaration.zig").CSSStyleDeclaration;
+pub const CSSRuleList = @import("css_rule_list.zig").CSSRuleList;
+
+pub const Interfaces = .{
+    Stylesheet,
+    CSSStylesheet,
+    CSSStyleDeclaration,
+    CSSRuleList,
+    @import("css_rule.zig").Interfaces,
+};
--- a/src/browser/cssom/stylesheet.zig
+++ b/src/browser/cssom/stylesheet.zig
@@ -0,0 +1,55 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+
+// https://developer.mozilla.org/en-US/docs/Web/API/StyleSheet#specifications
+pub const StyleSheet = struct {
+    disabled: bool = false,
+    href: []const u8 = "",
+    owner_node: ?*parser.Node = null,
+    parent_stylesheet: ?*StyleSheet = null,
+    title: []const u8 = "",
+    type: []const u8 = "text/css",
+
+    pub fn get_disabled(self: *const StyleSheet) bool {
+        return self.disabled;
+    }
+
+    pub fn get_href(self: *const StyleSheet) []const u8 {
+        return self.href;
+    }
+
+    // TODO: media
+
+    pub fn get_ownerNode(self: *const StyleSheet) ?*parser.Node {
+        return self.owner_node;
+    }
+
+    pub fn get_parentStyleSheet(self: *const StyleSheet) ?*StyleSheet {
+        return self.parent_stylesheet;
+    }
+
+    pub fn get_title(self: *const StyleSheet) []const u8 {
+        return self.title;
+    }
+
+    pub fn get_type(self: *const StyleSheet) []const u8 {
+        return self.type;
+    }
+};
--- a/src/browser/datauri.zig
+++ b/src/browser/datauri.zig
@@ -0,0 +1,79 @@
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+// Represents https://developer.mozilla.org/en-US/docs/Web/URI/Reference/Schemes/data
+pub const DataURI = struct {
+    was_base64_encoded: bool,
+    // The contents in the uri. It will be base64 decoded but not prepared in
+    // any way for mime.charset.
+    data: []const u8,
+
+    // Parses data:[<media-type>][;base64],<data>
+    pub fn parse(allocator: Allocator, src: []const u8) !?DataURI {
+        if (!std.mem.startsWith(u8, src, "data:")) {
+            return null;
+        }
+
+        const uri = src[5..];
+        const data_starts = std.mem.indexOfScalar(u8, uri, ',') orelse return null;
+
+        // Extract the encoding.
+        var metadata = uri[0..data_starts];
+        var base64_encoded = false;
+        if (std.mem.endsWith(u8, metadata, ";base64")) {
+            base64_encoded = true;
+            metadata = metadata[0 .. metadata.len - 7];
+        }
+
+        // TODO: Extract mime type. This not trivial because Mime.parse requires
+        // a []u8 and might mutate the src. And, the DataURI.parse references atm
+        // do not have deinit calls.
+
+        // Prepare the data.
+        var data = uri[data_starts + 1 ..];
+        if (base64_encoded) {
+            const decoder = std.base64.standard.Decoder;
+            const decoded_size = try decoder.calcSizeForSlice(data);
+
+            const buffer = try allocator.alloc(u8, decoded_size);
+            errdefer allocator.free(buffer);
+
+            try decoder.decode(buffer, data);
+            data = buffer;
+        }
+
+        return .{
+            .was_base64_encoded = base64_encoded,
+            .data = data,
+        };
+    }
+
+    pub fn deinit(self: *const DataURI, allocator: Allocator) void {
+        if (self.was_base64_encoded) {
+            allocator.free(self.data);
+        }
+    }
+};
+
+const testing = std.testing;
+test "DataURI: parse valid" {
+    try test_valid("data:text/javascript; charset=utf-8;base64,Zm9v", "foo");
+    try test_valid("data:text/javascript; charset=utf-8;,foo", "foo");
+    try test_valid("data:,foo", "foo");
+}
+
+test "DataURI: parse invalid" {
+    try test_cannot_parse("atad:,foo");
+    try test_cannot_parse("data:foo");
+    try test_cannot_parse("data:");
+}
+
+fn test_valid(uri: []const u8, expected: []const u8) !void {
+    const data_uri = try DataURI.parse(std.testing.allocator, uri) orelse return error.TestFailed;
+    defer data_uri.deinit(testing.allocator);
+    try testing.expectEqualStrings(expected, data_uri.data);
+}
+
+fn test_cannot_parse(uri: []const u8) !void {
+    try testing.expectEqual(null, DataURI.parse(std.testing.allocator, uri));
+}
--- a/src/browser/dom/Animation.zig
+++ b/src/browser/dom/Animation.zig
@@ -0,0 +1,126 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Page = @import("../page.zig").Page;
+const JsObject = @import("../env.zig").JsObject;
+const Promise = @import("../env.zig").Promise;
+const PromiseResolver = @import("../env.zig").PromiseResolver;
+
+const Animation = @This();
+
+effect: ?JsObject,
+timeline: ?JsObject,
+ready_resolver: ?PromiseResolver,
+finished_resolver: ?PromiseResolver,
+
+pub fn constructor(effect: ?JsObject, timeline: ?JsObject) !Animation {
+    return .{
+        .effect = if (effect) |eo| try eo.persist() else null,
+        .timeline = if (timeline) |to| try to.persist() else null,
+        .ready_resolver = null,
+        .finished_resolver = null,
+    };
+}
+
+pub fn get_playState(self: *const Animation) []const u8 {
+    _ = self;
+    return "finished";
+}
+
+pub fn get_pending(self: *const Animation) bool {
+    _ = self;
+    return false;
+}
+
+pub fn get_finished(self: *Animation, page: *Page) !Promise {
+    if (self.finished_resolver == null) {
+        const resolver = page.main_context.createPromiseResolver();
+        try resolver.resolve(self);
+        self.finished_resolver = resolver;
+    }
+    return self.finished_resolver.?.promise();
+}
+
+pub fn get_ready(self: *Animation, page: *Page) !Promise {
+    // never resolved, because we're always "finished"
+    if (self.ready_resolver == null) {
+        const resolver = page.main_context.createPromiseResolver();
+        self.ready_resolver = resolver;
+    }
+    return self.ready_resolver.?.promise();
+}
+
+pub fn get_effect(self: *const Animation) ?JsObject {
+    return self.effect;
+}
+
+pub fn set_effect(self: *Animation, effect: JsObject) !void {
+    self.effect = try effect.persist();
+}
+
+pub fn get_timeline(self: *const Animation) ?JsObject {
+    return self.timeline;
+}
+
+pub fn set_timeline(self: *Animation, timeline: JsObject) !void {
+    self.timeline = try timeline.persist();
+}
+
+pub fn _play(self: *const Animation) void {
+    _ = self;
+}
+
+pub fn _pause(self: *const Animation) void {
+    _ = self;
+}
+
+pub fn _cancel(self: *const Animation) void {
+    _ = self;
+}
+
+pub fn _finish(self: *const Animation) void {
+    _ = self;
+}
+
+pub fn _reverse(self: *const Animation) void {
+    _ = self;
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.Animation" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{ .html = "" });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let a1 = document.createElement('div').animate(null, null)", null },
+        .{ "a1.playState", "finished" },
+        .{ "let cb = [];", null },
+        .{ "a1.ready.then(() => { cb.push('ready') })", null },
+        .{
+            \\ a1.finished.then((x) => {
+            \\   cb.push('finished');
+            \\   cb.push(x == a1);
+            \\ })
+            ,
+            null,
+        },
+        .{ "cb", "finished,true" },
+    }, .{});
+}
--- a/src/browser/dom/MessageChannel.zig
+++ b/src/browser/dom/MessageChannel.zig
@@ -0,0 +1,361 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+
+const Env = @import("../env.zig").Env;
+const Page = @import("../page.zig").Page;
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+const EventHandler = @import("../events/event.zig").EventHandler;
+
+const JsObject = Env.JsObject;
+const Function = Env.Function;
+const Allocator = std.mem.Allocator;
+
+const MAX_QUEUE_SIZE = 10;
+
+pub const Interfaces = .{ MessageChannel, MessagePort };
+
+const MessageChannel = @This();
+
+port1: *MessagePort,
+port2: *MessagePort,
+
+pub fn constructor(page: *Page) !MessageChannel {
+    // Why do we allocate this rather than storing directly in the struct?
+    // https://github.com/lightpanda-io/project/discussions/165
+    const port1 = try page.arena.create(MessagePort);
+    const port2 = try page.arena.create(MessagePort);
+    port1.* = .{
+        .pair = port2,
+    };
+    port2.* = .{
+        .pair = port1,
+    };
+
+    return .{
+        .port1 = port1,
+        .port2 = port2,
+    };
+}
+
+pub fn get_port1(self: *const MessageChannel) *MessagePort {
+    return self.port1;
+}
+
+pub fn get_port2(self: *const MessageChannel) *MessagePort {
+    return self.port2;
+}
+
+pub const MessagePort = struct {
+    pub const prototype = *EventTarget;
+
+    proto: parser.EventTargetTBase = .{ .internal_target_type = .message_port },
+
+    pair: *MessagePort,
+    closed: bool = false,
+    started: bool = false,
+    onmessage_cbk: ?Function = null,
+    onmessageerror_cbk: ?Function = null,
+    // This is the queue of messages to dispatch to THIS MessagePort when the
+    // MessagePort is started.
+    queue: std.ArrayListUnmanaged(JsObject) = .empty,
+
+    pub const PostMessageOption = union(enum) {
+        transfer: JsObject,
+        options: Opts,
+
+        pub const Opts = struct {
+            transfer: JsObject,
+        };
+    };
+
+    pub fn _postMessage(self: *MessagePort, obj: JsObject, opts_: ?PostMessageOption, page: *Page) !void {
+        if (self.closed) {
+            return;
+        }
+
+        if (opts_ != null) {
+            log.warn(.web_api, "not implemented", .{ .feature = "MessagePort postMessage options" });
+            return error.NotImplemented;
+        }
+
+        try self.pair.dispatchOrQueue(obj, page.arena);
+    }
+
+    // Start impacts the ability to receive a message.
+    // Given pair1 (started) and pair2 (not started), then:
+    //    pair2.postMessage('x'); //will be dispatched to pair1.onmessage
+    //    pair1.postMessage('x'); // will be queued until pair2 is started
+    pub fn _start(self: *MessagePort) !void {
+        if (self.started) {
+            return;
+        }
+        self.started = true;
+        for (self.queue.items) |data| {
+            try self.dispatch(data);
+        }
+        // we'll never use this queue again, but it's allocated with an arena
+        // we don't even need to clear it, but it seems a bit safer to do at
+        // least that
+        self.queue.clearRetainingCapacity();
+    }
+
+    // Closing seems to stop both the publishing and receiving of messages,
+    // effectively rendering the channel useless. It cannot be reversed.
+    pub fn _close(self: *MessagePort) void {
+        self.closed = true;
+        self.pair.closed = true;
+    }
+
+    pub fn get_onmessage(self: *MessagePort) ?Function {
+        return self.onmessage_cbk;
+    }
+    pub fn get_onmessageerror(self: *MessagePort) ?Function {
+        return self.onmessageerror_cbk;
+    }
+
+    pub fn set_onmessage(self: *MessagePort, listener: EventHandler.Listener, page: *Page) !void {
+        if (self.onmessage_cbk) |cbk| {
+            try self.unregister("message", cbk.id);
+        }
+        self.onmessage_cbk = try self.register(page.arena, "message", listener);
+
+        // When onmessage is set directly, then it's like start() was called.
+        // If addEventListener('message') is used, the app has to call start()
+        // explicitly.
+        try self._start();
+    }
+
+    pub fn set_onmessageerror(self: *MessagePort, listener: EventHandler.Listener, page: *Page) !void {
+        if (self.onmessageerror_cbk) |cbk| {
+            try self.unregister("messageerror", cbk.id);
+        }
+        self.onmessageerror_cbk = try self.register(page.arena, "messageerror", listener);
+    }
+
+    // called from our pair. If port1.postMessage("x") is called, then this
+    // will be called on port2.
+    fn dispatchOrQueue(self: *MessagePort, obj: JsObject, arena: Allocator) !void {
+        // our pair should have checked this already
+        std.debug.assert(self.closed == false);
+
+        if (self.started) {
+            return self.dispatch(try obj.persist());
+        }
+
+        if (self.queue.items.len > MAX_QUEUE_SIZE) {
+            // This isn't part of the spec, but not putting a limit is reckless
+            return error.MessageQueueLimit;
+        }
+        return self.queue.append(arena, try obj.persist());
+    }
+
+    fn dispatch(self: *MessagePort, obj: JsObject) !void {
+        // obj is already persisted, don't use `MessageEvent.constructor`, but
+        // go directly to `init`, which assumes persisted objects.
+        var evt = try MessageEvent.init(.{ .data = obj });
+        _ = try parser.eventTargetDispatchEvent(
+            parser.toEventTarget(MessagePort, self),
+            @as(*parser.Event, @ptrCast(&evt)),
+        );
+    }
+
+    fn register(
+        self: *MessagePort,
+        alloc: Allocator,
+        typ: []const u8,
+        listener: EventHandler.Listener,
+    ) !?Function {
+        const target = @as(*parser.EventTarget, @ptrCast(self));
+        const eh = (try EventHandler.register(alloc, target, typ, listener, null)) orelse unreachable;
+        return eh.callback;
+    }
+
+    fn unregister(self: *MessagePort, typ: []const u8, cbk_id: usize) !void {
+        const et = @as(*parser.EventTarget, @ptrCast(self));
+        const lst = try parser.eventTargetHasListener(et, typ, false, cbk_id);
+        if (lst == null) {
+            return;
+        }
+        try parser.eventTargetRemoveEventListener(et, typ, lst.?, false);
+    }
+};
+
+pub const MessageEvent = struct {
+    const Event = @import("../events/event.zig").Event;
+    const DOMException = @import("exceptions.zig").DOMException;
+
+    pub const prototype = *Event;
+    pub const Exception = DOMException;
+    pub const union_make_copy = true;
+
+    proto: parser.Event,
+    data: ?JsObject,
+
+    // You would think if port1 sends to port2, the source would be port2
+    // (which is how I read the documentation), but it appears to always be
+    // null. It can always be set explicitly via the constructor;
+    source: ?JsObject,
+
+    origin: []const u8,
+
+    // This is used for Server-Sent events. Appears to always be an empty
+    // string for MessagePort messages.
+    last_event_id: []const u8,
+
+    // This might be related to the "transfer" option of postMessage which
+    // we don't yet support. For "normal" message, it's always an empty array.
+    // Though it could be set explicitly via the constructor
+    ports: []*MessagePort,
+
+    const Options = struct {
+        data: ?JsObject = null,
+        source: ?JsObject = null,
+        origin: []const u8 = "",
+        lastEventId: []const u8 = "",
+        ports: []*MessagePort = &.{},
+    };
+
+    pub fn constructor(opts: Options) !MessageEvent {
+        return init(.{
+            .data = if (opts.data) |obj| try obj.persist() else null,
+            .source = if (opts.source) |obj| try obj.persist() else null,
+            .ports = opts.ports,
+            .origin = opts.origin,
+            .lastEventId = opts.lastEventId,
+        });
+    }
+
+    // This is like "constructor", but it assumes JsObjects have already been
+    // persisted. Necessary because this `new MessageEvent()` can be called
+    // directly from JS OR from a port.postMessage. In the latter case, data
+    // may have already been persisted (as it might need to be queued);
+    fn init(opts: Options) !MessageEvent {
+        const event = try parser.eventCreate();
+        defer parser.eventDestroy(event);
+        try parser.eventInit(event, "message", .{});
+        try parser.eventSetInternalType(event, .message_event);
+
+        return .{
+            .proto = event.*,
+            .data = opts.data,
+            .source = opts.source,
+            .ports = opts.ports,
+            .origin = opts.origin,
+            .last_event_id = opts.lastEventId,
+        };
+    }
+
+    pub fn get_data(self: *const MessageEvent) !?JsObject {
+        return self.data;
+    }
+
+    pub fn get_origin(self: *const MessageEvent) []const u8 {
+        return self.origin;
+    }
+
+    pub fn get_source(self: *const MessageEvent) ?JsObject {
+        return self.source;
+    }
+
+    pub fn get_ports(self: *const MessageEvent) []*MessagePort {
+        return self.ports;
+    }
+
+    pub fn get_lastEventId(self: *const MessageEvent) []const u8 {
+        return self.last_event_id;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.MessageChannel" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .html = "",
+    });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "const mc1 = new MessageChannel()", null },
+        .{ "mc1.port1 == mc1.port1", "true" },
+        .{ "mc1.port2 == mc1.port2", "true" },
+        .{ "mc1.port1 != mc1.port2", "true" },
+        .{ "mc1.port1.postMessage('msg1');", "undefined" },
+        .{
+            \\ let message = null;
+            \\ let target = null;
+            \\ let currentTarget = null;
+            \\ mc1.port2.onmessage = (e) => {
+            \\   message = e.data;
+            \\   target = e.target;
+            \\   currentTarget = e.currentTarget;
+            \\ };
+            ,
+            null,
+        },
+        //  as soon as onmessage is called, queued messages are delivered
+        .{ "message", "msg1" },
+        .{ "target == mc1.port2", "true" },
+        .{ "currentTarget == mc1.port2", "true" },
+
+        .{ "mc1.port1.postMessage('msg2');", "undefined" },
+        .{ "message", "msg2" },
+        .{ "target == mc1.port2", "true" },
+        .{ "currentTarget == mc1.port2", "true" },
+
+        .{ "message = null", null },
+        .{ "mc1.port1.close();", null },
+        .{ "mc1.port1.postMessage('msg3');", "undefined" },
+        .{ "message", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const mc2 = new MessageChannel()", null },
+        .{ "mc2.port2.postMessage('msg1');", "undefined" },
+        .{ "mc2.port1.postMessage('msg2');", "undefined" },
+        .{
+            \\ let message1 = null;
+            \\ mc2.port1.addEventListener('message', (e) => {
+            \\   message1 = e.data;
+            \\ });
+            ,
+            null,
+        },
+        .{
+            \\ let message2 = null;
+            \\ mc2.port2.addEventListener('message', (e) => {
+            \\   message2 = e.data;
+            \\ });
+            ,
+            null,
+        },
+        .{ "message1", "null" },
+        .{ "message2", "null" },
+        .{ "mc2.port2.start()", null },
+
+        .{ "message1", "null" },
+        .{ "message2", "msg2" },
+        .{ "message2 = null", null },
+
+        .{ "mc2.port1.start()", null },
+        .{ "message1", "msg1" },
+        .{ "message2", "null" },
+    }, .{});
+}
--- a/src/browser/dom/attribute.zig
+++ b/src/browser/dom/attribute.zig
@@ -0,0 +1,101 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+const parser = @import("../netsurf.zig");
+
+const Node = @import("node.zig").Node;
+
+// WEB IDL https://dom.spec.whatwg.org/#attr
+pub const Attr = struct {
+    pub const Self = parser.Attribute;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub fn get_namespaceURI(self: *parser.Attribute) !?[]const u8 {
+        return try parser.nodeGetNamespace(parser.attributeToNode(self));
+    }
+
+    pub fn get_prefix(self: *parser.Attribute) !?[]const u8 {
+        return try parser.nodeGetPrefix(parser.attributeToNode(self));
+    }
+
+    pub fn get_localName(self: *parser.Attribute) ![]const u8 {
+        return try parser.nodeLocalName(parser.attributeToNode(self));
+    }
+
+    pub fn get_name(self: *parser.Attribute) ![]const u8 {
+        return try parser.attributeGetName(self);
+    }
+
+    pub fn get_value(self: *parser.Attribute) !?[]const u8 {
+        return try parser.attributeGetValue(self);
+    }
+
+    pub fn set_value(self: *parser.Attribute, v: []const u8) !?[]const u8 {
+        if (try parser.attributeGetOwnerElement(self)) |el| {
+            // if possible, go through the element, as that triggers a
+            // DOMAttrModified event (which MutationObserver cares about)
+            const name = try parser.attributeGetName(self);
+            try parser.elementSetAttribute(el, name, v);
+        } else {
+            try parser.attributeSetValue(self, v);
+        }
+        return v;
+    }
+
+    pub fn get_ownerElement(self: *parser.Attribute) !?*parser.Element {
+        return try parser.attributeGetOwnerElement(self);
+    }
+
+    pub fn get_specified(_: *parser.Attribute) bool {
+        return true;
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Attribute" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let a = document.createAttributeNS('foo', 'bar')", "undefined" },
+        .{ "a.namespaceURI", "foo" },
+        .{ "a.prefix", "null" },
+        .{ "a.localName", "bar" },
+        .{ "a.name", "bar" },
+        .{ "a.value", "" },
+        // TODO: libdom has a bug here: the created attr has no parent, it
+        // causes a panic w/ libdom when setting the value.
+        //.{ "a.value = 'nok'", "nok" },
+        .{ "a.ownerElement", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let b = document.getElementById('link').getAttributeNode('class')", "undefined" },
+        .{ "b.name", "class" },
+        .{ "b.value", "ok" },
+        .{ "b.value = 'nok'", "nok" },
+        .{ "b.value", "nok" },
+        .{ "b.value = null", "null" },
+        .{ "b.value", "null" },
+        .{ "b.value = 'ok'", "ok" },
+        .{ "b.ownerElement.id", "link" },
+    }, .{});
+}
--- a/src/browser/dom/cdata_section.zig
+++ b/src/browser/dom/cdata_section.zig
@@ -0,0 +1,28 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+
+const Text = @import("text.zig").Text;
+
+// https://dom.spec.whatwg.org/#cdatasection
+pub const CDATASection = struct {
+    pub const Self = parser.CDATASection;
+    pub const prototype = *Text;
+    pub const subtype = .node;
+};
--- a/src/browser/dom/character_data.zig
+++ b/src/browser/dom/character_data.zig
@@ -0,0 +1,196 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+
+const Node = @import("node.zig").Node;
+const Comment = @import("comment.zig").Comment;
+const Text = @import("text.zig");
+const ProcessingInstruction = @import("processing_instruction.zig").ProcessingInstruction;
+const HTMLElem = @import("../html/elements.zig");
+
+// CharacterData interfaces
+pub const Interfaces = .{
+    Comment,
+    Text.Text,
+    Text.Interfaces,
+    ProcessingInstruction,
+};
+
+// CharacterData implementation
+pub const CharacterData = struct {
+    pub const Self = parser.CharacterData;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    // JS funcs
+    // --------
+
+    // Read attributes
+
+    pub fn get_length(self: *parser.CharacterData) !u32 {
+        return try parser.characterDataLength(self);
+    }
+
+    pub fn get_nextElementSibling(self: *parser.CharacterData) !?HTMLElem.Union {
+        const res = try parser.nodeNextElementSibling(parser.characterDataToNode(self));
+        if (res == null) {
+            return null;
+        }
+        return try HTMLElem.toInterface(HTMLElem.Union, res.?);
+    }
+
+    pub fn get_previousElementSibling(self: *parser.CharacterData) !?HTMLElem.Union {
+        const res = try parser.nodePreviousElementSibling(parser.characterDataToNode(self));
+        if (res == null) {
+            return null;
+        }
+        return try HTMLElem.toInterface(HTMLElem.Union, res.?);
+    }
+
+    // Read/Write attributes
+
+    pub fn get_data(self: *parser.CharacterData) ![]const u8 {
+        return try parser.characterDataData(self);
+    }
+
+    pub fn set_data(self: *parser.CharacterData, data: []const u8) !void {
+        return try parser.characterDataSetData(self, data);
+    }
+
+    // JS methods
+    // ----------
+
+    pub fn _appendData(self: *parser.CharacterData, data: []const u8) !void {
+        return try parser.characterDataAppendData(self, data);
+    }
+
+    pub fn _deleteData(self: *parser.CharacterData, offset: u32, count: u32) !void {
+        return try parser.characterDataDeleteData(self, offset, count);
+    }
+
+    pub fn _insertData(self: *parser.CharacterData, offset: u32, data: []const u8) !void {
+        return try parser.characterDataInsertData(self, offset, data);
+    }
+
+    pub fn _replaceData(self: *parser.CharacterData, offset: u32, count: u32, data: []const u8) !void {
+        return try parser.characterDataReplaceData(self, offset, count, data);
+    }
+
+    pub fn _substringData(self: *parser.CharacterData, offset: u32, count: u32) ![]const u8 {
+        return try parser.characterDataSubstringData(self, offset, count);
+    }
+
+    // netsurf's CharacterData (text, comment) doesn't implement the
+    // dom_node_get_attributes and thus will crash if we try to call nodeIsEqualNode.
+    pub fn _isEqualNode(self: *parser.CharacterData, other_node: *parser.Node) !bool {
+        if (try parser.nodeType(@alignCast(@ptrCast(self))) != try parser.nodeType(other_node)) {
+            return false;
+        }
+
+        const other: *parser.CharacterData = @ptrCast(other_node);
+        if (std.mem.eql(u8, try get_data(self), try get_data(other)) == false) {
+            return false;
+        }
+
+        return true;
+    }
+
+    pub fn _before(self: *parser.CharacterData, nodes: []const Node.NodeOrText) !void {
+        const ref_node = parser.characterDataToNode(self);
+        return Node.before(ref_node, nodes);
+    }
+
+    pub fn _after(self: *parser.CharacterData, nodes: []const Node.NodeOrText) !void {
+        const ref_node = parser.characterDataToNode(self);
+        return Node.after(ref_node, nodes);
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.CharacterData" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let link = document.getElementById('link')", "undefined" },
+        .{ "let cdata = link.firstChild", "undefined" },
+        .{ "cdata.data", "OK" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.data = 'OK modified'", "OK modified" },
+        .{ "cdata.data === 'OK modified'", "true" },
+        .{ "cdata.data = 'OK'", "OK" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.length === 2", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.nextElementSibling === null", "true" },
+        // create a next element
+        .{ "let next = document.createElement('a')", "undefined" },
+        .{ "link.appendChild(next, cdata) !== undefined", "true" },
+        .{ "cdata.nextElementSibling.localName === 'a' ", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.previousElementSibling === null", "true" },
+        // create a prev element
+        .{ "let prev = document.createElement('div')", "undefined" },
+        .{ "link.insertBefore(prev, cdata) !== undefined", "true" },
+        .{ "cdata.previousElementSibling.localName === 'div' ", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.appendData(' modified')", "undefined" },
+        .{ "cdata.data === 'OK modified' ", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.deleteData('OK'.length, ' modified'.length)", "undefined" },
+        .{ "cdata.data == 'OK'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.insertData('OK'.length-1, 'modified')", "undefined" },
+        .{ "cdata.data == 'OmodifiedK'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.replaceData('OK'.length-1, 'modified'.length, 'replaced')", "undefined" },
+        .{ "cdata.data == 'OreplacedK'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.substringData('OK'.length-1, 'replaced'.length) == 'replaced'", "true" },
+        .{ "cdata.substringData('OK'.length-1, 0) == ''", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "cdata.substringData('OK'.length-1, 'replaced'.length) == 'replaced'", "true" },
+        .{ "cdata.substringData('OK'.length-1, 0) == ''", "true" },
+    }, .{});
+}
--- a/src/browser/dom/comment.zig
+++ b/src/browser/dom/comment.zig
@@ -0,0 +1,54 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+
+const CharacterData = @import("character_data.zig").CharacterData;
+
+const Page = @import("../page.zig").Page;
+
+// https://dom.spec.whatwg.org/#interface-comment
+pub const Comment = struct {
+    pub const Self = parser.Comment;
+    pub const prototype = *CharacterData;
+    pub const subtype = .node;
+
+    pub fn constructor(data: ?[]const u8, page: *const Page) !*parser.Comment {
+        return parser.documentCreateComment(
+            parser.documentHTMLToDocument(page.window.document),
+            data orelse "",
+        );
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Comment" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let comment = new Comment('foo')", "undefined" },
+        .{ "comment.data", "foo" },
+
+        .{ "let emptycomment = new Comment()", "undefined" },
+        .{ "emptycomment.data", "" },
+    }, .{});
+}
--- a/src/browser/dom/css.zig
+++ b/src/browser/dom/css.zig
@@ -0,0 +1,80 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+
+const css = @import("../css/css.zig");
+const Node = @import("../css/libdom.zig").Node;
+const NodeList = @import("nodelist.zig").NodeList;
+
+const MatchFirst = struct {
+    n: ?*parser.Node = null,
+
+    pub fn match(m: *MatchFirst, n: Node) !void {
+        m.n = n.node;
+    }
+};
+
+pub fn querySelector(alloc: std.mem.Allocator, n: *parser.Node, selector: []const u8) !?*parser.Node {
+    const ps = try css.parse(alloc, selector, .{ .accept_pseudo_elts = true });
+    defer ps.deinit(alloc);
+
+    var m = MatchFirst{};
+
+    _ = try css.matchFirst(ps, Node{ .node = n }, &m);
+    return m.n;
+}
+
+const MatchAll = struct {
+    alloc: std.mem.Allocator,
+    nl: NodeList,
+
+    fn init(alloc: std.mem.Allocator) MatchAll {
+        return .{
+            .alloc = alloc,
+            .nl = .{},
+        };
+    }
+
+    fn deinit(m: *MatchAll) void {
+        m.nl.deinit(m.alloc);
+    }
+
+    pub fn match(m: *MatchAll, n: Node) !void {
+        try m.nl.append(m.alloc, n.node);
+    }
+
+    fn toOwnedList(m: *MatchAll) NodeList {
+        // reset it.
+        defer m.nl = .{};
+        return m.nl;
+    }
+};
+
+pub fn querySelectorAll(alloc: std.mem.Allocator, n: *parser.Node, selector: []const u8) !NodeList {
+    const ps = try css.parse(alloc, selector, .{ .accept_pseudo_elts = true });
+    defer ps.deinit(alloc);
+
+    var m = MatchAll.init(alloc);
+    defer m.deinit();
+
+    try css.matchAll(ps, Node{ .node = n }, &m);
+    return m.toOwnedList();
+}
--- a/src/browser/dom/document.zig
+++ b/src/browser/dom/document.zig
@@ -0,0 +1,498 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const Node = @import("node.zig").Node;
+const NodeList = @import("nodelist.zig").NodeList;
+const NodeUnion = @import("node.zig").Union;
+
+const collection = @import("html_collection.zig");
+const css = @import("css.zig");
+
+const Element = @import("element.zig").Element;
+const ElementUnion = @import("element.zig").Union;
+const TreeWalker = @import("tree_walker.zig").TreeWalker;
+const CSSStyleSheet = @import("../cssom/css_stylesheet.zig").CSSStyleSheet;
+const NodeIterator = @import("node_iterator.zig").NodeIterator;
+const Range = @import("range.zig").Range;
+
+const Env = @import("../env.zig").Env;
+
+const DOMImplementation = @import("implementation.zig").DOMImplementation;
+
+// WEB IDL https://dom.spec.whatwg.org/#document
+pub const Document = struct {
+    pub const Self = parser.Document;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub fn constructor(page: *const Page) !*parser.DocumentHTML {
+        const doc = try parser.documentCreateDocument(
+            try parser.documentHTMLGetTitle(page.window.document),
+        );
+
+        // we have to work w/ document instead of html document.
+        const ddoc = parser.documentHTMLToDocument(doc);
+        const ccur = parser.documentHTMLToDocument(page.window.document);
+        try parser.documentSetDocumentURI(ddoc, try parser.documentGetDocumentURI(ccur));
+        try parser.documentSetInputEncoding(ddoc, try parser.documentGetInputEncoding(ccur));
+
+        return doc;
+    }
+
+    // JS funcs
+    // --------
+    pub fn get_implementation(_: *parser.Document) DOMImplementation {
+        return DOMImplementation{};
+    }
+
+    pub fn get_documentElement(self: *parser.Document) !?ElementUnion {
+        const e = try parser.documentGetDocumentElement(self);
+        if (e == null) return null;
+        return try Element.toInterface(e.?);
+    }
+
+    pub fn get_documentURI(self: *parser.Document) ![]const u8 {
+        return try parser.documentGetDocumentURI(self);
+    }
+
+    pub fn get_URL(self: *parser.Document) ![]const u8 {
+        return try get_documentURI(self);
+    }
+
+    // TODO implement contentType
+    pub fn get_contentType(self: *parser.Document) []const u8 {
+        _ = self;
+        return "text/html";
+    }
+
+    // TODO implement compactMode
+    pub fn get_compatMode(self: *parser.Document) []const u8 {
+        _ = self;
+        return "CSS1Compat";
+    }
+
+    pub fn get_characterSet(self: *parser.Document) ![]const u8 {
+        return try parser.documentGetInputEncoding(self);
+    }
+
+    // alias of get_characterSet
+    pub fn get_charset(self: *parser.Document) ![]const u8 {
+        return try get_characterSet(self);
+    }
+
+    // alias of get_characterSet
+    pub fn get_inputEncoding(self: *parser.Document) ![]const u8 {
+        return try get_characterSet(self);
+    }
+
+    pub fn get_doctype(self: *parser.Document) !?*parser.DocumentType {
+        return try parser.documentGetDoctype(self);
+    }
+
+    pub fn _createEvent(_: *parser.Document, eventCstr: []const u8) !*parser.Event {
+        // TODO: for now only "Event" constructor is supported
+        // see table on https://dom.spec.whatwg.org/#dom-document-createevent $2
+        if (std.ascii.eqlIgnoreCase(eventCstr, "Event") or std.ascii.eqlIgnoreCase(eventCstr, "Events")) {
+            return try parser.eventCreate();
+        }
+        return parser.DOMError.NotSupported;
+    }
+
+    pub fn _getElementById(self: *parser.Document, id: []const u8) !?ElementUnion {
+        const e = try parser.documentGetElementById(self, id) orelse return null;
+        return try Element.toInterface(e);
+    }
+
+    pub fn _createElement(self: *parser.Document, tag_name: []const u8) !ElementUnion {
+        // The element’s namespace is the HTML namespace when document is an HTML document
+        // https://dom.spec.whatwg.org/#ref-for-dom-document-createelement%E2%91%A0
+        const e = try parser.documentCreateElementNS(self, "http://www.w3.org/1999/xhtml", tag_name);
+        return Element.toInterface(e);
+    }
+
+    pub fn _createElementNS(self: *parser.Document, ns: []const u8, tag_name: []const u8) !ElementUnion {
+        const e = try parser.documentCreateElementNS(self, ns, tag_name);
+        return try Element.toInterface(e);
+    }
+
+    // We can't simply use libdom dom_document_get_elements_by_tag_name here.
+    // Indeed, netsurf implemented a previous dom spec when
+    // getElementsByTagName returned a NodeList.
+    // But since
+    // https://github.com/whatwg/dom/commit/190700b7c12ecfd3b5ebdb359ab1d6ea9cbf7749
+    // the spec changed to return an HTMLCollection instead.
+    // That's why we reimplemented getElementsByTagName by using an
+    // HTMLCollection in zig here.
+    pub fn _getElementsByTagName(
+        self: *parser.Document,
+        tag_name: []const u8,
+        page: *Page,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(page.arena, parser.documentToNode(self), tag_name, true);
+    }
+
+    pub fn _getElementsByClassName(
+        self: *parser.Document,
+        classNames: []const u8,
+        page: *Page,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByClassName(page.arena, parser.documentToNode(self), classNames, true);
+    }
+
+    pub fn _createDocumentFragment(self: *parser.Document) !*parser.DocumentFragment {
+        return try parser.documentCreateDocumentFragment(self);
+    }
+
+    pub fn _createTextNode(self: *parser.Document, data: []const u8) !*parser.Text {
+        return try parser.documentCreateTextNode(self, data);
+    }
+
+    pub fn _createCDATASection(self: *parser.Document, data: []const u8) !*parser.CDATASection {
+        return try parser.documentCreateCDATASection(self, data);
+    }
+
+    pub fn _createComment(self: *parser.Document, data: []const u8) !*parser.Comment {
+        return try parser.documentCreateComment(self, data);
+    }
+
+    pub fn _createProcessingInstruction(self: *parser.Document, target: []const u8, data: []const u8) !*parser.ProcessingInstruction {
+        return try parser.documentCreateProcessingInstruction(self, target, data);
+    }
+
+    pub fn _importNode(self: *parser.Document, node: *parser.Node, deep: ?bool) !NodeUnion {
+        const n = try parser.documentImportNode(self, node, deep orelse false);
+        return try Node.toInterface(n);
+    }
+
+    pub fn _adoptNode(self: *parser.Document, node: *parser.Node) !NodeUnion {
+        const n = try parser.documentAdoptNode(self, node);
+        return try Node.toInterface(n);
+    }
+
+    pub fn _createAttribute(self: *parser.Document, name: []const u8) !*parser.Attribute {
+        return try parser.documentCreateAttribute(self, name);
+    }
+
+    pub fn _createAttributeNS(self: *parser.Document, ns: []const u8, qname: []const u8) !*parser.Attribute {
+        return try parser.documentCreateAttributeNS(self, ns, qname);
+    }
+
+    // ParentNode
+    // https://dom.spec.whatwg.org/#parentnode
+    pub fn get_children(self: *parser.Document) !collection.HTMLCollection {
+        return try collection.HTMLCollectionChildren(parser.documentToNode(self), false);
+    }
+
+    pub fn get_firstElementChild(self: *parser.Document) !?ElementUnion {
+        const elt = try parser.documentGetDocumentElement(self) orelse return null;
+        return try Element.toInterface(elt);
+    }
+
+    pub fn get_lastElementChild(self: *parser.Document) !?ElementUnion {
+        const elt = try parser.documentGetDocumentElement(self) orelse return null;
+        return try Element.toInterface(elt);
+    }
+
+    pub fn get_childElementCount(self: *parser.Document) !u32 {
+        _ = try parser.documentGetDocumentElement(self) orelse return 0;
+        return 1;
+    }
+
+    pub fn _querySelector(self: *parser.Document, selector: []const u8, page: *Page) !?ElementUnion {
+        if (selector.len == 0) return null;
+
+        const n = try css.querySelector(page.call_arena, parser.documentToNode(self), selector);
+
+        if (n == null) return null;
+
+        return try Element.toInterface(parser.nodeToElement(n.?));
+    }
+
+    pub fn _querySelectorAll(self: *parser.Document, selector: []const u8, page: *Page) !NodeList {
+        return css.querySelectorAll(page.arena, parser.documentToNode(self), selector);
+    }
+
+    pub fn _prepend(self: *parser.Document, nodes: []const Node.NodeOrText) !void {
+        return Node.prepend(parser.documentToNode(self), nodes);
+    }
+
+    pub fn _append(self: *parser.Document, nodes: []const Node.NodeOrText) !void {
+        return Node.append(parser.documentToNode(self), nodes);
+    }
+
+    pub fn _replaceChildren(self: *parser.Document, nodes: []const Node.NodeOrText) !void {
+        return Node.replaceChildren(parser.documentToNode(self), nodes);
+    }
+
+    pub fn _createTreeWalker(_: *parser.Document, root: *parser.Node, what_to_show: ?u32, filter: ?TreeWalker.TreeWalkerOpts) !TreeWalker {
+        return try TreeWalker.init(root, what_to_show, filter);
+    }
+
+    pub fn _createNodeIterator(_: *parser.Document, root: *parser.Node, what_to_show: ?u32, filter: ?NodeIterator.NodeIteratorOpts) !NodeIterator {
+        return try NodeIterator.init(root, what_to_show, filter);
+    }
+
+    pub fn getActiveElement(self: *parser.Document, page: *Page) !?*parser.Element {
+        if (page.getNodeState(@alignCast(@ptrCast(self)))) |state| {
+            if (state.active_element) |ae| {
+                return ae;
+            }
+        }
+
+        if (try parser.documentHTMLBody(page.window.document)) |body| {
+            return @alignCast(@ptrCast(body));
+        }
+
+        return try parser.documentGetDocumentElement(self);
+    }
+
+    pub fn get_activeElement(self: *parser.Document, page: *Page) !?ElementUnion {
+        const ae = (try getActiveElement(self, page)) orelse return null;
+        return try Element.toInterface(ae);
+    }
+
+    // TODO: some elements can't be focused, like if they're disabled
+    // but there doesn't seem to be a generic way to check this. For example
+    // we could look for the "disabled" attribute, but that's only meaningful
+    // on certain types, and libdom's vtable doesn't seem to expose this.
+    pub fn setFocus(self: *parser.Document, e: *parser.ElementHTML, page: *Page) !void {
+        const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
+        state.active_element = @ptrCast(e);
+    }
+
+    pub fn _createRange(_: *parser.Document, page: *Page) Range {
+        return Range.constructor(page);
+    }
+
+    // TODO: dummy implementation
+    pub fn get_styleSheets(_: *parser.Document) []CSSStyleSheet {
+        return &.{};
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Document" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .url = "about:blank",
+    });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "document.__proto__.__proto__.constructor.name", "Document" },
+        .{ "document.__proto__.__proto__.__proto__.constructor.name", "Node" },
+        .{ "document.__proto__.__proto__.__proto__.__proto__.constructor.name", "EventTarget" },
+
+        .{ "let newdoc = new Document()", "undefined" },
+        .{ "newdoc.documentElement", "null" },
+        .{ "newdoc.children.length", "0" },
+        .{ "newdoc.getElementsByTagName('*').length", "0" },
+        .{ "newdoc.getElementsByTagName('*').item(0)", "null" },
+        .{ "newdoc.inputEncoding === document.inputEncoding", "true" },
+        .{ "newdoc.documentURI === document.documentURI", "true" },
+        .{ "newdoc.URL === document.URL", "true" },
+        .{ "newdoc.compatMode === document.compatMode", "true" },
+        .{ "newdoc.characterSet === document.characterSet", "true" },
+        .{ "newdoc.charset === document.charset", "true" },
+        .{ "newdoc.contentType === document.contentType", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let getElementById = document.getElementById('content')", "undefined" },
+        .{ "getElementById.constructor.name", "HTMLDivElement" },
+        .{ "getElementById.localName", "div" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let getElementsByTagName = document.getElementsByTagName('p')", "undefined" },
+        .{ "getElementsByTagName.length", "2" },
+        .{ "getElementsByTagName.item(0).localName", "p" },
+        .{ "getElementsByTagName.item(1).localName", "p" },
+        .{ "let getElementsByTagNameAll = document.getElementsByTagName('*')", "undefined" },
+        .{ "getElementsByTagNameAll.length", "8" },
+        .{ "getElementsByTagNameAll.item(0).localName", "html" },
+        .{ "getElementsByTagNameAll.item(7).localName", "p" },
+        .{ "getElementsByTagNameAll.namedItem('para-empty-child').localName", "span" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let ok = document.getElementsByClassName('ok')", "undefined" },
+        .{ "ok.length", "2" },
+        .{ "let empty = document.getElementsByClassName('empty')", "undefined" },
+        .{ "empty.length", "1" },
+        .{ "let emptyok = document.getElementsByClassName('empty ok')", "undefined" },
+        .{ "emptyok.length", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let e = document.documentElement", "undefined" },
+        .{ "e.localName", "html" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.characterSet", "UTF-8" },
+        .{ "document.charset", "UTF-8" },
+        .{ "document.inputEncoding", "UTF-8" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.compatMode", "CSS1Compat" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.contentType", "text/html" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.documentURI", "about:blank" },
+        .{ "document.URL", "about:blank" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let impl = document.implementation", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let d = new Document()", "undefined" },
+        .{ "d.characterSet", "UTF-8" },
+        .{ "d.URL", "about:blank" },
+        .{ "d.documentURI", "about:blank" },
+        .{ "d.compatMode", "CSS1Compat" },
+        .{ "d.contentType", "text/html" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var v = document.createDocumentFragment()", "undefined" },
+        .{ "v.nodeName", "#document-fragment" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var v = document.createTextNode('foo')", "undefined" },
+        .{ "v.nodeName", "#text" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var v = document.createCDATASection('foo')", "undefined" },
+        .{ "v.nodeName", "#cdata-section" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var v = document.createComment('foo')", "undefined" },
+        .{ "v.nodeName", "#comment" },
+        .{ "let v2 = v.cloneNode()", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let pi = document.createProcessingInstruction('foo', 'bar')", "undefined" },
+        .{ "pi.target", "foo" },
+        .{ "let pi2 = pi.cloneNode()", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let nimp = document.getElementById('content')", "undefined" },
+        .{ "var v = document.importNode(nimp)", "undefined" },
+        .{ "v.nodeName", "DIV" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var v = document.createAttribute('foo')", "undefined" },
+        .{ "v.nodeName", "foo" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.children.length", "1" },
+        .{ "document.children.item(0).nodeName", "HTML" },
+        .{ "document.firstElementChild.nodeName", "HTML" },
+        .{ "document.lastElementChild.nodeName", "HTML" },
+        .{ "document.childElementCount", "1" },
+
+        .{ "let nd = new Document()", "undefined" },
+        .{ "nd.children.length", "0" },
+        .{ "nd.children.item(0)", "null" },
+        .{ "nd.firstElementChild", "null" },
+        .{ "nd.lastElementChild", "null" },
+        .{ "nd.childElementCount", "0" },
+
+        .{ "let emptydoc = document.createElement('html')", "undefined" },
+        .{ "emptydoc.prepend(document.createElement('html'))", "undefined" },
+
+        .{ "let emptydoc2 = document.createElement('html')", "undefined" },
+        .{ "emptydoc2.append(document.createElement('html'))", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.querySelector('')", "null" },
+        .{ "document.querySelector('*').nodeName", "HTML" },
+        .{ "document.querySelector('#content').id", "content" },
+        .{ "document.querySelector('#para').id", "para" },
+        .{ "document.querySelector('.ok').id", "link" },
+        .{ "document.querySelector('a ~ p').id", "para-empty" },
+        .{ "document.querySelector(':root').nodeName", "HTML" },
+
+        .{ "document.querySelectorAll('p').length", "2" },
+        .{
+            \\  Array.from(document.querySelectorAll('#content > p#para-empty'))
+            \\    .map(row => row.querySelector('span').textContent)
+            \\    .length;
+            ,
+            "1",
+        },
+
+        .{ "document.querySelectorAll('.\\\\:popover-open').length", "0" },
+        .{ "document.querySelectorAll('.foo\\\\:bar').length", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.activeElement === document.body", "true" },
+        .{ "document.getElementById('link').focus()", "undefined" },
+        .{ "document.activeElement === document.getElementById('link')", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.styleSheets.length", "0" },
+    }, .{});
+
+    // this test breaks the doc structure, keep it at the end of the test
+    // suite.
+    try runner.testCases(&.{
+        .{ "let nadop = document.getElementById('content')", "undefined" },
+        .{ "var v = document.adoptNode(nadop)", "undefined" },
+        .{ "v.nodeName", "DIV" },
+    }, .{});
+
+    const Case = testing.JsRunner.Case;
+    const tags = comptime parser.Tag.all();
+    var createElements: [(tags.len) * 2]Case = undefined;
+    inline for (tags, 0..) |tag, i| {
+        const tag_name = @tagName(tag);
+        createElements[i * 2] = Case{
+            "var " ++ tag_name ++ "Elem = document.createElement('" ++ tag_name ++ "')",
+            "undefined",
+        };
+        createElements[(i * 2) + 1] = Case{
+            tag_name ++ "Elem.localName",
+            tag_name,
+        };
+    }
+    try runner.testCases(&createElements, .{});
+}
--- a/src/browser/dom/document_fragment.zig
+++ b/src/browser/dom/document_fragment.zig
@@ -0,0 +1,124 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const css = @import("css.zig");
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+const NodeList = @import("nodelist.zig").NodeList;
+const Element = @import("element.zig").Element;
+const ElementUnion = @import("element.zig").Union;
+const collection = @import("html_collection.zig");
+
+const Node = @import("node.zig").Node;
+
+// WEB IDL https://dom.spec.whatwg.org/#documentfragment
+pub const DocumentFragment = struct {
+    pub const Self = parser.DocumentFragment;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub fn constructor(page: *const Page) !*parser.DocumentFragment {
+        return parser.documentCreateDocumentFragment(
+            parser.documentHTMLToDocument(page.window.document),
+        );
+    }
+
+    pub fn _isEqualNode(self: *parser.DocumentFragment, other_node: *parser.Node) !bool {
+        const other_type = try parser.nodeType(other_node);
+        if (other_type != .document_fragment) {
+            return false;
+        }
+        _ = self;
+        return true;
+    }
+
+    pub fn _prepend(self: *parser.DocumentFragment, nodes: []const Node.NodeOrText) !void {
+        return Node.prepend(parser.documentFragmentToNode(self), nodes);
+    }
+
+    pub fn _append(self: *parser.DocumentFragment, nodes: []const Node.NodeOrText) !void {
+        return Node.append(parser.documentFragmentToNode(self), nodes);
+    }
+
+    pub fn _replaceChildren(self: *parser.DocumentFragment, nodes: []const Node.NodeOrText) !void {
+        return Node.replaceChildren(parser.documentFragmentToNode(self), nodes);
+    }
+
+    pub fn _querySelector(self: *parser.DocumentFragment, selector: []const u8, page: *Page) !?ElementUnion {
+        if (selector.len == 0) return null;
+
+        const n = try css.querySelector(page.call_arena, parser.documentFragmentToNode(self), selector);
+
+        if (n == null) return null;
+
+        return try Element.toInterface(parser.nodeToElement(n.?));
+    }
+
+    pub fn _querySelectorAll(self: *parser.DocumentFragment, selector: []const u8, page: *Page) !NodeList {
+        return css.querySelectorAll(page.arena, parser.documentFragmentToNode(self), selector);
+    }
+
+    pub fn get_childElementCount(self: *parser.DocumentFragment) !u32 {
+        var children = try get_children(self);
+        return children.get_length();
+    }
+
+    pub fn get_children(self: *parser.DocumentFragment) !collection.HTMLCollection {
+        return collection.HTMLCollectionChildren(parser.documentFragmentToNode(self), false);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.DocumentFragment" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "const dc = new DocumentFragment()", "undefined" },
+        .{ "dc.constructor.name", "DocumentFragment" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const dc1 = new DocumentFragment()", "undefined" },
+        .{ "const dc2 = new DocumentFragment()", "undefined" },
+        .{ "dc1.isEqualNode(dc1)", "true" },
+        .{ "dc1.isEqualNode(dc2)", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let f = document.createDocumentFragment()", null },
+        .{ "let d = document.createElement('div');", null },
+        .{ "d.childElementCount", "0" },
+
+        .{ "d.id = 'x';", null },
+        .{ "document.getElementById('x') == null;", "true" },
+        .{ "f.append(d);", null },
+        .{ "f.childElementCount", "1" },
+        .{ "f.children[0].id", "x" },
+        .{ "document.getElementById('x') == null;", "true" },
+
+        .{ "document.getElementsByTagName('body')[0].append(f.cloneNode(true));", null },
+        .{ "document.getElementById('x') != null;", "true" },
+
+        .{ "document.querySelector('.hello')", "null" },
+        .{ "document.querySelectorAll('.hello').length", "0" },
+
+        .{ "document.querySelector('#x').id", "x" },
+        .{ "document.querySelectorAll('#x')[0].id", "x" },
+    }, .{});
+}
--- a/src/browser/dom/document_type.zig
+++ b/src/browser/dom/document_type.zig
@@ -0,0 +1,80 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+
+const Node = @import("node.zig").Node;
+
+// WEB IDL https://dom.spec.whatwg.org/#documenttype
+pub const DocumentType = struct {
+    pub const Self = parser.DocumentType;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub fn get_name(self: *parser.DocumentType) ![]const u8 {
+        return try parser.documentTypeGetName(self);
+    }
+
+    pub fn get_publicId(self: *parser.DocumentType) ![]const u8 {
+        return try parser.documentTypeGetPublicId(self);
+    }
+
+    pub fn get_systemId(self: *parser.DocumentType) ![]const u8 {
+        return try parser.documentTypeGetSystemId(self);
+    }
+
+    // netsurf's DocumentType doesn't implement the dom_node_get_attributes
+    // and thus will crash if we try to call nodeIsEqualNode.
+    pub fn _isEqualNode(self: *parser.DocumentType, other_node: *parser.Node) !bool {
+        if (try parser.nodeType(other_node) != .document_type) {
+            return false;
+        }
+
+        const other: *parser.DocumentType = @ptrCast(other_node);
+        if (std.mem.eql(u8, try get_name(self), try get_name(other)) == false) {
+            return false;
+        }
+        if (std.mem.eql(u8, try get_publicId(self), try get_publicId(other)) == false) {
+            return false;
+        }
+        if (std.mem.eql(u8, try get_systemId(self), try get_systemId(other)) == false) {
+            return false;
+        }
+        return true;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.DocumentType" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let dt1 = document.implementation.createDocumentType('qname1', 'pid1', 'sys1');", "undefined" },
+        .{ "let dt2 = document.implementation.createDocumentType('qname2', 'pid2', 'sys2');", "undefined" },
+        .{ "let dt3 = document.implementation.createDocumentType('qname1', 'pid1', 'sys1');", "undefined" },
+        .{ "dt1.isEqualNode(dt1)", "true" },
+        .{ "dt1.isEqualNode(dt3)", "true" },
+        .{ "dt1.isEqualNode(dt2)", "false" },
+        .{ "dt2.isEqualNode(dt3)", "false" },
+        .{ "dt1.isEqualNode(document)", "false" },
+        .{ "document.isEqualNode(dt1)", "false" },
+    }, .{});
+}
--- a/src/browser/dom/dom.zig
+++ b/src/browser/dom/dom.zig
@@ -0,0 +1,57 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const DOMException = @import("exceptions.zig").DOMException;
+const EventTarget = @import("event_target.zig").EventTarget;
+const DOMImplementation = @import("implementation.zig").DOMImplementation;
+const NamedNodeMap = @import("namednodemap.zig").NamedNodeMap;
+const DOMTokenList = @import("token_list.zig");
+const NodeList = @import("nodelist.zig");
+const Node = @import("node.zig");
+const ResizeObserver = @import("resize_observer.zig");
+const MutationObserver = @import("mutation_observer.zig");
+const IntersectionObserver = @import("intersection_observer.zig");
+const DOMParser = @import("dom_parser.zig").DOMParser;
+const TreeWalker = @import("tree_walker.zig").TreeWalker;
+const NodeIterator = @import("node_iterator.zig").NodeIterator;
+const NodeFilter = @import("node_filter.zig").NodeFilter;
+const PerformanceObserver = @import("performance_observer.zig").PerformanceObserver;
+
+pub const Interfaces = .{
+    DOMException,
+    EventTarget,
+    DOMImplementation,
+    NamedNodeMap,
+    NamedNodeMap.Iterator,
+    DOMTokenList.Interfaces,
+    NodeList.Interfaces,
+    Node.Node,
+    Node.Interfaces,
+    ResizeObserver.Interfaces,
+    MutationObserver.Interfaces,
+    IntersectionObserver.Interfaces,
+    DOMParser,
+    TreeWalker,
+    NodeIterator,
+    NodeFilter,
+    @import("performance.zig").Interfaces,
+    PerformanceObserver,
+    @import("range.zig").Interfaces,
+    @import("Animation.zig"),
+    @import("MessageChannel.zig").Interfaces,
+};
--- a/src/browser/dom/dom_parser.zig
+++ b/src/browser/dom/dom_parser.zig
@@ -0,0 +1,47 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+
+// https://developer.mozilla.org/en-US/docs/Web/API/DOMParser
+pub const DOMParser = struct {
+    pub fn constructor() !DOMParser {
+        return .{};
+    }
+
+    pub fn _parseFromString(_: *DOMParser, string: []const u8, mime_type: []const u8) !*parser.DocumentHTML {
+        if (!std.mem.eql(u8, mime_type, "text/html")) {
+            // TODO: Support XML
+            return error.TypeError;
+        }
+
+        return try parser.documentHTMLParseFromStr(string);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.DOMParser" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "const dp = new DOMParser()", "undefined" },
+        .{ "dp.parseFromString('<div>abc</div>', 'text/html')", "[object HTMLDocument]" },
+    }, .{});
+}
--- a/src/browser/dom/element.zig
+++ b/src/browser/dom/element.zig
@@ -0,0 +1,789 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const css = @import("css.zig");
+const log = @import("../../log.zig");
+const dump = @import("../dump.zig");
+const collection = @import("html_collection.zig");
+
+const Node = @import("node.zig").Node;
+const Walker = @import("walker.zig").WalkerDepthFirst;
+const NodeList = @import("nodelist.zig").NodeList;
+const HTMLElem = @import("../html/elements.zig");
+const ShadowRoot = @import("../dom/shadow_root.zig").ShadowRoot;
+
+const Animation = @import("Animation.zig");
+const JsObject = @import("../env.zig").JsObject;
+
+pub const Union = @import("../html/elements.zig").Union;
+
+// WEB IDL https://dom.spec.whatwg.org/#element
+pub const Element = struct {
+    pub const Self = parser.Element;
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub const DOMRect = struct {
+        x: f64,
+        y: f64,
+        width: f64,
+        height: f64,
+        bottom: f64,
+        right: f64,
+        top: f64,
+        left: f64,
+    };
+
+    pub fn toInterface(e: *parser.Element) !Union {
+        return try HTMLElem.toInterface(Union, e);
+        // SVGElement and MathML are not supported yet.
+    }
+
+    // JS funcs
+    // --------
+
+    pub fn get_namespaceURI(self: *parser.Element) !?[]const u8 {
+        return try parser.nodeGetNamespace(parser.elementToNode(self));
+    }
+
+    pub fn get_prefix(self: *parser.Element) !?[]const u8 {
+        return try parser.nodeGetPrefix(parser.elementToNode(self));
+    }
+
+    pub fn get_localName(self: *parser.Element) ![]const u8 {
+        return try parser.nodeLocalName(parser.elementToNode(self));
+    }
+
+    pub fn get_tagName(self: *parser.Element) ![]const u8 {
+        return try parser.nodeName(parser.elementToNode(self));
+    }
+
+    pub fn get_id(self: *parser.Element) ![]const u8 {
+        return try parser.elementGetAttribute(self, "id") orelse "";
+    }
+
+    pub fn set_id(self: *parser.Element, id: []const u8) !void {
+        return try parser.elementSetAttribute(self, "id", id);
+    }
+
+    pub fn get_className(self: *parser.Element) ![]const u8 {
+        return try parser.elementGetAttribute(self, "class") orelse "";
+    }
+
+    pub fn set_className(self: *parser.Element, class: []const u8) !void {
+        return try parser.elementSetAttribute(self, "class", class);
+    }
+
+    pub fn get_slot(self: *parser.Element) ![]const u8 {
+        return try parser.elementGetAttribute(self, "slot") orelse "";
+    }
+
+    pub fn set_slot(self: *parser.Element, slot: []const u8) !void {
+        return try parser.elementSetAttribute(self, "slot", slot);
+    }
+
+    pub fn get_classList(self: *parser.Element) !*parser.TokenList {
+        return try parser.tokenListCreate(self, "class");
+    }
+
+    pub fn get_attributes(self: *parser.Element) !*parser.NamedNodeMap {
+        // An element must have non-nil attributes.
+        return try parser.nodeGetAttributes(parser.elementToNode(self)) orelse unreachable;
+    }
+
+    pub fn get_innerHTML(self: *parser.Element, page: *Page) ![]const u8 {
+        var buf = std.ArrayList(u8).init(page.arena);
+        try dump.writeChildren(parser.elementToNode(self), .{}, buf.writer());
+        return buf.items;
+    }
+
+    pub fn get_outerHTML(self: *parser.Element, page: *Page) ![]const u8 {
+        var buf = std.ArrayList(u8).init(page.arena);
+        try dump.writeNode(parser.elementToNode(self), .{}, buf.writer());
+        return buf.items;
+    }
+
+    pub fn set_innerHTML(self: *parser.Element, str: []const u8) !void {
+        const node = parser.elementToNode(self);
+        const doc = try parser.nodeOwnerDocument(node) orelse return parser.DOMError.WrongDocument;
+        // parse the fragment
+        const fragment = try parser.documentParseFragmentFromStr(doc, str);
+
+        // remove existing children
+        try Node.removeChildren(node);
+
+        // I'm not sure what the exact behavior is supposed to be. Initially,
+        // we were only copying the body of the document fragment. But it seems
+        // like head elements should be copied too. Specifically, some sites
+        // create script tags via innerHTML, which we need to capture.
+        // If you play with this in a browser, you should notice that the
+        // behavior is different depending on whether you're in a blank page
+        // or an actual document. In a blank page, something like:
+        //    x.innerHTML = '<script></script>';
+        // does _not_ create an empty script, but in a real page, it does. Weird.
+        const fragment_node = parser.documentFragmentToNode(fragment);
+        const html = try parser.nodeFirstChild(fragment_node) orelse return;
+        const head = try parser.nodeFirstChild(html) orelse return;
+        {
+            // First, copy some of the head element
+            const children = try parser.nodeGetChildNodes(head);
+            const ln = try parser.nodeListLength(children);
+            for (0..ln) |_| {
+                // always index 0, because nodeAppendChild moves the node out of
+                // the nodeList and into the new tree
+                const child = try parser.nodeListItem(children, 0) orelse continue;
+                _ = try parser.nodeAppendChild(node, child);
+            }
+        }
+
+        {
+            const body = try parser.nodeNextSibling(head) orelse return;
+            const children = try parser.nodeGetChildNodes(body);
+            const ln = try parser.nodeListLength(children);
+            for (0..ln) |_| {
+                // always index 0, because nodeAppendChild moves the node out of
+                // the nodeList and into the new tree
+                const child = try parser.nodeListItem(children, 0) orelse continue;
+                _ = try parser.nodeAppendChild(node, child);
+            }
+        }
+    }
+
+    // The closest() method of the Element interface traverses the element and its parents (heading toward the document root) until it finds a node that matches the specified CSS selector.
+    // Returns the closest ancestor Element or itself, which matches the selectors. If there are no such element, null.
+    pub fn _closest(self: *parser.Element, selector: []const u8, page: *Page) !?*parser.Element {
+        const cssParse = @import("../css/css.zig").parse;
+        const CssNodeWrap = @import("../css/libdom.zig").Node;
+        const select = try cssParse(page.call_arena, selector, .{});
+
+        var current: CssNodeWrap = .{ .node = parser.elementToNode(self) };
+        while (true) {
+            if (try select.match(current)) {
+                if (!current.isElement()) {
+                    log.err(.browser, "closest invalid type", .{ .type = try current.tag() });
+                    return null;
+                }
+                return parser.nodeToElement(current.node);
+            }
+            current = try current.parent() orelse return null;
+        }
+    }
+
+    // don't use parser.nodeHasAttributes(...) because that returns true/false
+    // based on the type, e.g. a node never as attributes, an element always has
+    // attributes. But, Element.hasAttributes is supposed to return true only
+    // if the element has at least 1 attribute.
+    pub fn _hasAttributes(self: *parser.Element) !bool {
+        // an element _must_ have at least an empty attribute
+        const node_map = try parser.nodeGetAttributes(parser.elementToNode(self)) orelse unreachable;
+        return try parser.namedNodeMapGetLength(node_map) > 0;
+    }
+
+    pub fn _getAttribute(self: *parser.Element, qname: []const u8) !?[]const u8 {
+        return try parser.elementGetAttribute(self, qname);
+    }
+
+    pub fn _getAttributeNS(self: *parser.Element, ns: []const u8, qname: []const u8) !?[]const u8 {
+        return try parser.elementGetAttributeNS(self, ns, qname);
+    }
+
+    pub fn _setAttribute(self: *parser.Element, qname: []const u8, value: []const u8) !void {
+        return try parser.elementSetAttribute(self, qname, value);
+    }
+
+    pub fn _setAttributeNS(self: *parser.Element, ns: []const u8, qname: []const u8, value: []const u8) !void {
+        return try parser.elementSetAttributeNS(self, ns, qname, value);
+    }
+
+    pub fn _removeAttribute(self: *parser.Element, qname: []const u8) !void {
+        return try parser.elementRemoveAttribute(self, qname);
+    }
+
+    pub fn _removeAttributeNS(self: *parser.Element, ns: []const u8, qname: []const u8) !void {
+        return try parser.elementRemoveAttributeNS(self, ns, qname);
+    }
+
+    pub fn _hasAttribute(self: *parser.Element, qname: []const u8) !bool {
+        return try parser.elementHasAttribute(self, qname);
+    }
+
+    pub fn _hasAttributeNS(self: *parser.Element, ns: []const u8, qname: []const u8) !bool {
+        return try parser.elementHasAttributeNS(self, ns, qname);
+    }
+
+    // https://dom.spec.whatwg.org/#dom-element-toggleattribute
+    pub fn _toggleAttribute(self: *parser.Element, qname: []u8, force: ?bool) !bool {
+        _ = std.ascii.lowerString(qname, qname);
+        const exists = try parser.elementHasAttribute(self, qname);
+
+        // If attribute is null, then:
+        if (!exists) {
+            // If force is not given or is true, create an attribute whose
+            // local name is qualifiedName, value is the empty string and node
+            // document is this’s node document, then append this attribute to
+            // this, and then return true.
+            if (force == null or force.?) {
+                try parser.elementSetAttribute(self, qname, "");
+                return true;
+            }
+            if (try parser.validateName(qname) == false) {
+                return parser.DOMError.InvalidCharacter;
+            }
+
+            // Return false.
+            return false;
+        }
+
+        // Otherwise, if force is not given or is false, remove an attribute
+        // given qualifiedName and this, and then return false.
+        if (force == null or !force.?) {
+            try parser.elementRemoveAttribute(self, qname);
+            return false;
+        }
+
+        // Return true.
+        return true;
+    }
+
+    pub fn _getAttributeNode(self: *parser.Element, name: []const u8) !?*parser.Attribute {
+        return try parser.elementGetAttributeNode(self, name);
+    }
+
+    pub fn _getAttributeNodeNS(self: *parser.Element, ns: []const u8, name: []const u8) !?*parser.Attribute {
+        return try parser.elementGetAttributeNodeNS(self, ns, name);
+    }
+
+    pub fn _setAttributeNode(self: *parser.Element, attr: *parser.Attribute) !?*parser.Attribute {
+        return try parser.elementSetAttributeNode(self, attr);
+    }
+
+    pub fn _setAttributeNodeNS(self: *parser.Element, attr: *parser.Attribute) !?*parser.Attribute {
+        return try parser.elementSetAttributeNodeNS(self, attr);
+    }
+
+    pub fn _removeAttributeNode(self: *parser.Element, attr: *parser.Attribute) !*parser.Attribute {
+        return try parser.elementRemoveAttributeNode(self, attr);
+    }
+
+    pub fn _getElementsByTagName(
+        self: *parser.Element,
+        tag_name: []const u8,
+        page: *Page,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(
+            page.arena,
+            parser.elementToNode(self),
+            tag_name,
+            false,
+        );
+    }
+
+    pub fn _getElementsByClassName(
+        self: *parser.Element,
+        classNames: []const u8,
+        page: *Page,
+    ) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByClassName(
+            page.arena,
+            parser.elementToNode(self),
+            classNames,
+            false,
+        );
+    }
+
+    // ParentNode
+    // https://dom.spec.whatwg.org/#parentnode
+    pub fn get_children(self: *parser.Element) !collection.HTMLCollection {
+        return try collection.HTMLCollectionChildren(parser.elementToNode(self), false);
+    }
+
+    pub fn get_firstElementChild(self: *parser.Element) !?Union {
+        var children = try get_children(self);
+        return try children._item(0);
+    }
+
+    pub fn get_lastElementChild(self: *parser.Element) !?Union {
+        // TODO we could check the last child node first, if it's an element,
+        // we can return it directly instead of looping twice over the
+        // children.
+        var children = try get_children(self);
+        const ln = try children.get_length();
+        if (ln == 0) return null;
+        return try children._item(ln - 1);
+    }
+
+    pub fn get_childElementCount(self: *parser.Element) !u32 {
+        var children = try get_children(self);
+        return try children.get_length();
+    }
+
+    // NonDocumentTypeChildNode
+    // https://dom.spec.whatwg.org/#interface-nondocumenttypechildnode
+    pub fn get_previousElementSibling(self: *parser.Element) !?Union {
+        const res = try parser.nodePreviousElementSibling(parser.elementToNode(self));
+        if (res == null) return null;
+        return try HTMLElem.toInterface(HTMLElem.Union, res.?);
+    }
+
+    pub fn get_nextElementSibling(self: *parser.Element) !?Union {
+        const res = try parser.nodeNextElementSibling(parser.elementToNode(self));
+        if (res == null) return null;
+        return try HTMLElem.toInterface(HTMLElem.Union, res.?);
+    }
+
+    fn getElementById(self: *parser.Element, id: []const u8) !?*parser.Node {
+        // walk over the node tree fo find the node by id.
+        const root = parser.elementToNode(self);
+        const walker = Walker{};
+        var next: ?*parser.Node = null;
+        while (true) {
+            next = try walker.get_next(root, next) orelse return null;
+            // ignore non-element nodes.
+            if (try parser.nodeType(next.?) != .element) {
+                continue;
+            }
+            const e = parser.nodeToElement(next.?);
+            if (std.mem.eql(u8, id, try get_id(e))) return next;
+        }
+    }
+
+    pub fn _querySelector(self: *parser.Element, selector: []const u8, page: *Page) !?Union {
+        if (selector.len == 0) return null;
+
+        const n = try css.querySelector(page.call_arena, parser.elementToNode(self), selector);
+
+        if (n == null) return null;
+
+        return try toInterface(parser.nodeToElement(n.?));
+    }
+
+    pub fn _querySelectorAll(self: *parser.Element, selector: []const u8, page: *Page) !NodeList {
+        return css.querySelectorAll(page.arena, parser.elementToNode(self), selector);
+    }
+
+    pub fn _prepend(self: *parser.Element, nodes: []const Node.NodeOrText) !void {
+        return Node.prepend(parser.elementToNode(self), nodes);
+    }
+
+    pub fn _append(self: *parser.Element, nodes: []const Node.NodeOrText) !void {
+        return Node.append(parser.elementToNode(self), nodes);
+    }
+
+    pub fn _before(self: *parser.Element, nodes: []const Node.NodeOrText) !void {
+        const ref_node = parser.elementToNode(self);
+        return Node.before(ref_node, nodes);
+    }
+
+    pub fn _after(self: *parser.Element, nodes: []const Node.NodeOrText) !void {
+        const ref_node = parser.elementToNode(self);
+        return Node.after(ref_node, nodes);
+    }
+
+    pub fn _replaceChildren(self: *parser.Element, nodes: []const Node.NodeOrText) !void {
+        return Node.replaceChildren(parser.elementToNode(self), nodes);
+    }
+
+    // A DOMRect object providing information about the size of an element and its position relative to the viewport.
+    // Returns a 0 DOMRect object if the element is eventually detached from the main window
+    pub fn _getBoundingClientRect(self: *parser.Element, page: *Page) !DOMRect {
+        // Since we are lazy rendering we need to do this check. We could store the renderer in a viewport such that it could cache these, but it would require tracking changes.
+        if (!try page.isNodeAttached(parser.elementToNode(self))) {
+            return DOMRect{
+                .x = 0,
+                .y = 0,
+                .width = 0,
+                .height = 0,
+                .bottom = 0,
+                .right = 0,
+                .top = 0,
+                .left = 0,
+            };
+        }
+        return page.renderer.getRect(self);
+    }
+
+    // Returns a collection of DOMRect objects that indicate the bounding rectangles for each CSS border box in a client.
+    // We do not render so it only always return the element's bounding rect.
+    // Returns an empty array if the element is eventually detached from the main window
+    pub fn _getClientRects(self: *parser.Element, page: *Page) ![]DOMRect {
+        if (!try page.isNodeAttached(parser.elementToNode(self))) {
+            return &.{};
+        }
+        const heap_ptr = try page.call_arena.create(DOMRect);
+        heap_ptr.* = try page.renderer.getRect(self);
+        return heap_ptr[0..1];
+    }
+
+    pub fn get_clientWidth(_: *parser.Element, page: *Page) u32 {
+        return page.renderer.width();
+    }
+
+    pub fn get_clientHeight(_: *parser.Element, page: *Page) u32 {
+        return page.renderer.height();
+    }
+
+    pub fn _matches(self: *parser.Element, selectors: []const u8, page: *Page) !bool {
+        const cssParse = @import("../css/css.zig").parse;
+        const CssNodeWrap = @import("../css/libdom.zig").Node;
+        const s = try cssParse(page.call_arena, selectors, .{});
+        return s.match(CssNodeWrap{ .node = parser.elementToNode(self) });
+    }
+
+    pub fn _scrollIntoViewIfNeeded(_: *parser.Element, center_if_needed: ?bool) void {
+        _ = center_if_needed;
+    }
+
+    const CheckVisibilityOpts = struct {
+        contentVisibilityAuto: bool,
+        opacityProperty: bool,
+        visibilityProperty: bool,
+    };
+
+    pub fn _checkVisibility(self: *parser.Element, opts: ?CheckVisibilityOpts) bool {
+        _ = self;
+        _ = opts;
+        return true;
+    }
+
+    const AttachShadowOpts = struct {
+        mode: []const u8, // must be specified
+    };
+    pub fn _attachShadow(self: *parser.Element, opts: AttachShadowOpts, page: *Page) !*ShadowRoot {
+        const mode = std.meta.stringToEnum(ShadowRoot.Mode, opts.mode) orelse return error.InvalidArgument;
+        const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
+        if (state.shadow_root) |sr| {
+            if (mode != sr.mode) {
+                // this is the behavior per the spec
+                return error.NotSupportedError;
+            }
+
+            try Node.removeChildren(@alignCast(@ptrCast(sr.proto)));
+            return sr;
+        }
+
+        // Not sure what to do if there is no owner document
+        const doc = try parser.nodeOwnerDocument(@ptrCast(self)) orelse return error.InvalidArgument;
+        const fragment = try parser.documentCreateDocumentFragment(doc);
+        const sr = try page.arena.create(ShadowRoot);
+        sr.* = .{
+            .host = self,
+            .mode = mode,
+            .proto = fragment,
+        };
+        state.shadow_root = sr;
+        return sr;
+    }
+
+    pub fn get_shadowRoot(self: *parser.Element, page: *Page) ?*ShadowRoot {
+        const state = page.getNodeState(@alignCast(@ptrCast(self))) orelse return null;
+        const sr = state.shadow_root orelse return null;
+        if (sr.mode == .closed) {
+            return null;
+        }
+        return sr;
+    }
+
+    pub fn _animate(self: *parser.Element, effect: JsObject, opts: JsObject) !Animation {
+        _ = self;
+        _ = opts;
+        return Animation.constructor(effect, null);
+    }
+
+    pub fn _remove(self: *parser.Element) !void {
+        // TODO: This hasn't been tested to make sure all references to this
+        // node are properly updated. A lot of libdom is lazy and will look
+        // for related elements JIT by walking the tree, but there could be
+        // cases in libdom or the Zig WebAPI where this reference is kept
+        const as_node: *parser.Node = @ptrCast(self);
+        const parent = try parser.nodeParentNode(as_node) orelse return;
+        _ = try Node._removeChild(parent, as_node);
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Element" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let g = document.getElementById('content')", "undefined" },
+        .{ "g.namespaceURI", "http://www.w3.org/1999/xhtml" },
+        .{ "g.prefix", "null" },
+        .{ "g.localName", "div" },
+        .{ "g.tagName", "DIV" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let gs = document.getElementById('content')", "undefined" },
+        .{ "gs.id", "content" },
+        .{ "gs.id = 'foo'", "foo" },
+        .{ "gs.id", "foo" },
+        .{ "gs.id = 'content'", "content" },
+        .{ "gs.className", "" },
+        .{ "let gs2 = document.getElementById('para-empty')", "undefined" },
+        .{ "gs2.className", "ok empty" },
+        .{ "gs2.className = 'foo bar baz'", "foo bar baz" },
+        .{ "gs2.className", "foo bar baz" },
+        .{ "gs2.className = 'ok empty'", "ok empty" },
+        .{ "let cl = gs2.classList", "undefined" },
+        .{ "cl.length", "2" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const el2 = document.createElement('div');", "undefined" },
+        .{ "el2.id = 'closest'; el2.className = 'ok';", "ok" },
+        .{ "el2.closest('#closest')", "[object HTMLDivElement]" },
+        .{ "el2.closest('.ok')", "[object HTMLDivElement]" },
+        .{ "el2.closest('#9000')", "null" },
+        .{ "el2.closest('.notok')", "null" },
+
+        .{ "const sp = document.createElement('span');", "undefined" },
+        .{ "el2.appendChild(sp);", "[object HTMLSpanElement]" },
+        .{ "sp.closest('#closest')", "[object HTMLDivElement]" },
+        .{ "sp.closest('#9000')", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let a = document.getElementById('content')", "undefined" },
+        .{ "a.hasAttributes()", "true" },
+        .{ "a.attributes.length", "1" },
+        .{ "a.getAttribute('id')", "content" },
+        .{ "a.attributes['id'].value", "content" },
+        .{
+            \\ let x = '';
+            \\ for (const attr of a.attributes) {
+            \\   x += attr.name + '=' + attr.value;
+            \\ }
+            \\ x;
+            ,
+            "id=content",
+        },
+
+        .{ "a.hasAttribute('foo')", "false" },
+        .{ "a.getAttribute('foo')", "null" },
+
+        .{ "a.setAttribute('foo', 'bar')", "undefined" },
+        .{ "a.hasAttribute('foo')", "true" },
+        .{ "a.getAttribute('foo')", "bar" },
+
+        .{ "a.setAttribute('foo', 'baz')", "undefined" },
+        .{ "a.hasAttribute('foo')", "true" },
+        .{ "a.getAttribute('foo')", "baz" },
+
+        .{ "a.removeAttribute('foo')", "undefined" },
+        .{ "a.hasAttribute('foo')", "false" },
+        .{ "a.getAttribute('foo')", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let b = document.getElementById('content')", "undefined" },
+        .{ "b.toggleAttribute('foo')", "true" },
+        .{ "b.hasAttribute('foo')", "true" },
+        .{ "b.getAttribute('foo')", "" },
+
+        .{ "b.toggleAttribute('foo')", "false" },
+        .{ "b.hasAttribute('foo')", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let c = document.getElementById('content')", "undefined" },
+        .{ "c.children.length", "3" },
+        .{ "c.firstElementChild.nodeName", "A" },
+        .{ "c.lastElementChild.nodeName", "P" },
+        .{ "c.childElementCount", "3" },
+
+        .{ "c.prepend(document.createTextNode('foo'))", "undefined" },
+        .{ "c.append(document.createTextNode('bar'))", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let d = document.getElementById('para')", "undefined" },
+        .{ "d.previousElementSibling.nodeName", "P" },
+        .{ "d.nextElementSibling", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let e = document.getElementById('content')", "undefined" },
+        .{ "e.querySelector('foo')", "null" },
+        .{ "e.querySelector('#foo')", "null" },
+        .{ "e.querySelector('#link').id", "link" },
+        .{ "e.querySelector('#para').id", "para" },
+        .{ "e.querySelector('*').id", "link" },
+        .{ "e.querySelector('')", "null" },
+        .{ "e.querySelector('*').id", "link" },
+        .{ "e.querySelector('#content')", "null" },
+        .{ "e.querySelector('#para').id", "para" },
+        .{ "e.querySelector('.ok').id", "link" },
+        .{ "e.querySelector('a ~ p').id", "para-empty" },
+
+        .{ "e.querySelectorAll('foo').length", "0" },
+        .{ "e.querySelectorAll('#foo').length", "0" },
+        .{ "e.querySelectorAll('#link').length", "1" },
+        .{ "e.querySelectorAll('#link').item(0).id", "link" },
+        .{ "e.querySelectorAll('#para').length", "1" },
+        .{ "e.querySelectorAll('#para').item(0).id", "para" },
+        .{ "e.querySelectorAll('*').length", "4" },
+        .{ "e.querySelectorAll('p').length", "2" },
+        .{ "e.querySelectorAll('.ok').item(0).id", "link" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let f = document.getElementById('content')", "undefined" },
+        .{ "let ff = document.createAttribute('foo')", "undefined" },
+        .{ "f.setAttributeNode(ff)", "null" },
+        .{ "f.getAttributeNode('foo').name", "foo" },
+        .{ "f.removeAttributeNode(ff).name", "foo" },
+        .{ "f.getAttributeNode('bar')", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.getElementById('para').innerHTML", " And" },
+        .{ "document.getElementById('para-empty').innerHTML.trim()", "<span id=\"para-empty-child\"></span>" },
+
+        .{ "let h = document.getElementById('para-empty')", "undefined" },
+        .{ "const prev = h.innerHTML", "undefined" },
+        .{ "h.innerHTML = '<p id=\"hello\">hello world</p>'", "<p id=\"hello\">hello world</p>" },
+        .{ "h.innerHTML", "<p id=\"hello\">hello world</p>" },
+        .{ "h.firstChild.nodeName", "P" },
+        .{ "h.firstChild.id", "hello" },
+        .{ "h.firstChild.textContent", "hello world" },
+        .{ "h.innerHTML = prev; true", "true" },
+        .{ "document.getElementById('para-empty').innerHTML.trim()", "<span id=\"para-empty-child\"></span>" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.getElementById('para').outerHTML", "<p id=\"para\"> And</p>" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.getElementById('para').clientWidth", "1" },
+        .{ "document.getElementById('para').clientHeight", "1" },
+
+        .{ "let r1 = document.getElementById('para').getBoundingClientRect()", "undefined" },
+        .{ "r1.x", "0" },
+        .{ "r1.y", "0" },
+        .{ "r1.width", "1" },
+        .{ "r1.height", "1" },
+
+        .{ "let r2 = document.getElementById('content').getBoundingClientRect()", "undefined" },
+        .{ "r2.x", "1" },
+        .{ "r2.y", "0" },
+        .{ "r2.width", "1" },
+        .{ "r2.height", "1" },
+
+        .{ "let r3 = document.getElementById('para').getBoundingClientRect()", "undefined" },
+        .{ "r3.x", "0" },
+        .{ "r3.y", "0" },
+        .{ "r3.width", "1" },
+        .{ "r3.height", "1" },
+
+        .{ "document.getElementById('para').clientWidth", "2" },
+        .{ "document.getElementById('para').clientHeight", "1" },
+
+        .{ "let r4 = document.createElement('div').getBoundingClientRect()", null },
+        .{ "r4.x", "0" },
+        .{ "r4.y", "0" },
+        .{ "r4.width", "0" },
+        .{ "r4.height", "0" },
+
+        // Test setup causes WrongDocument or HierarchyRequest error unlike in chrome/firefox
+        // .{ // An element of another document, even if created from the main document, is not rendered.
+        //     \\ let div5 = document.createElement('div');
+        //     \\ const newDoc = document.implementation.createHTMLDocument("New Document");
+        //     \\ newDoc.body.appendChild(div5);
+        //     \\ let r5 = div5.getBoundingClientRect();
+        //     ,
+        //     null,
+        // },
+        // .{ "r5.x", "0" },
+        // .{ "r5.y", "0" },
+        // .{ "r5.width", "0" },
+        // .{ "r5.height", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const el = document.createElement('div');", "undefined" },
+        .{ "el.id = 'matches'; el.className = 'ok';", "ok" },
+        .{ "el.matches('#matches')", "true" },
+        .{ "el.matches('.ok')", "true" },
+        .{ "el.matches('#9000')", "false" },
+        .{ "el.matches('.notok')", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const el3 = document.createElement('div');", "undefined" },
+        .{ "el3.scrollIntoViewIfNeeded();", "undefined" },
+        .{ "el3.scrollIntoViewIfNeeded(false);", "undefined" },
+    }, .{});
+
+    // before
+    try runner.testCases(&.{
+        .{ "const before_container = document.createElement('div');", "undefined" },
+        .{ "document.append(before_container);", "undefined" },
+        .{ "const b1 = document.createElement('div');", "undefined" },
+        .{ "before_container.append(b1);", "undefined" },
+
+        .{ "const b1_a = document.createElement('p');", "undefined" },
+        .{ "b1.before(b1_a, 'over 9000');", "undefined" },
+        .{ "before_container.innerHTML", "<p></p>over 9000<div></div>" },
+    }, .{});
+
+    // after
+    try runner.testCases(&.{
+        .{ "const after_container = document.createElement('div');", "undefined" },
+        .{ "document.append(after_container);", "undefined" },
+        .{ "const a1 = document.createElement('div');", "undefined" },
+        .{ "after_container.append(a1);", "undefined" },
+
+        .{ "const a1_a = document.createElement('p');", "undefined" },
+        .{ "a1.after('over 9000', a1_a);", "undefined" },
+        .{ "after_container.innerHTML", "<div></div>over 9000<p></p>" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var div1 = document.createElement('div');", null },
+        .{ "div1.innerHTML = \"  <link/><table></table><a href='/a'>a</a><input type='checkbox'/>\"", null },
+        .{ "div1.getElementsByTagName('a').length", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.createElement('a').hasAttributes()", "false" },
+        .{ "var fc; (fc = document.createElement('div')).innerHTML = '<script><\\/script>'", null },
+        .{ "fc.outerHTML", "<div><script></script></div>" },
+
+        .{ "fc; (fc = document.createElement('div')).innerHTML = '<script><\\/script><p>hello</p>'", null },
+        .{ "fc.outerHTML", "<div><script></script><p>hello</p></div>" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const rm = document.createElement('div')", null },
+        .{ "rm.id = 'to-remove'", null },
+        .{ "document.getElementsByTagName('body')[0].appendChild(rm)", null },
+        .{ "document.getElementById('to-remove') != null", "true" },
+        .{ "rm.remove()", "undefined" },
+        .{ "document.getElementById('to-remove') != null", "false" },
+    }, .{});
+}
--- a/src/browser/dom/event_target.zig
+++ b/src/browser/dom/event_target.zig
@@ -0,0 +1,272 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Env = @import("../env.zig").Env;
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const EventHandler = @import("../events/event.zig").EventHandler;
+
+const DOMException = @import("exceptions.zig").DOMException;
+const nod = @import("node.zig");
+
+pub const Union = union(enum) {
+    node: nod.Union,
+    xhr: *@import("../xhr/xhr.zig").XMLHttpRequest,
+    plain: *parser.EventTarget,
+    message_port: *@import("MessageChannel.zig").MessagePort,
+};
+
+// EventTarget implementation
+pub const EventTarget = struct {
+    pub const Self = parser.EventTarget;
+    pub const Exception = DOMException;
+
+    // Extend libdom event target for pure zig struct.
+    base: parser.EventTargetTBase = parser.EventTargetTBase{ .internal_target_type = .plain },
+
+    pub fn toInterface(et: *parser.EventTarget, page: *Page) !Union {
+        // libdom assumes that all event targets are libdom nodes. They are not.
+
+        switch (try parser.eventTargetInternalType(et)) {
+            .libdom_node => {
+                return .{ .node = try nod.Node.toInterface(@as(*parser.Node, @ptrCast(et))) };
+            },
+            .plain => return .{ .plain = et },
+            .abort_signal => {
+                // AbortSignal is a special case, it has its own internal type.
+                // We return it as a node, but we need to handle it differently.
+                return .{ .node = .{ .AbortSignal = @fieldParentPtr("proto", @as(*parser.EventTargetTBase, @ptrCast(et))) } };
+            },
+            .window => {
+                // The window is a common non-node target, but it's easy to handle as its a singleton.
+                std.debug.assert(@intFromPtr(et) == @intFromPtr(&page.window.base));
+                return .{ .node = .{ .Window = &page.window } };
+            },
+            .xhr => {
+                const XMLHttpRequestEventTarget = @import("../xhr/event_target.zig").XMLHttpRequestEventTarget;
+                const base: *XMLHttpRequestEventTarget = @fieldParentPtr("base", @as(*parser.EventTargetTBase, @ptrCast(et)));
+                return .{ .xhr = @fieldParentPtr("proto", base) };
+            },
+            .message_port => {
+                return .{ .message_port = @fieldParentPtr("proto", @as(*parser.EventTargetTBase, @ptrCast(et))) };
+            },
+            else => return error.MissingEventTargetType,
+        }
+    }
+
+    // JS funcs
+    // --------
+    pub fn constructor(page: *Page) !*parser.EventTarget {
+        const et = try page.arena.create(EventTarget);
+        return @ptrCast(&et.base);
+    }
+
+    pub fn _addEventListener(
+        self: *parser.EventTarget,
+        typ: []const u8,
+        listener: EventHandler.Listener,
+        opts: ?EventHandler.Opts,
+        page: *Page,
+    ) !void {
+        _ = try EventHandler.register(page.arena, self, typ, listener, opts);
+    }
+
+    const RemoveEventListenerOpts = union(enum) {
+        opts: Opts,
+        capture: bool,
+
+        const Opts = struct {
+            capture: ?bool,
+        };
+    };
+
+    pub fn _removeEventListener(
+        self: *parser.EventTarget,
+        typ: []const u8,
+        listener: EventHandler.Listener,
+        opts_: ?RemoveEventListenerOpts,
+    ) !void {
+        var capture = false;
+        if (opts_) |opts| {
+            capture = switch (opts) {
+                .capture => |c| c,
+                .opts => |o| o.capture orelse false,
+            };
+        }
+
+        const cbk = (try listener.callback(self)) orelse return;
+
+        // check if event target has already this listener
+        const lst = try parser.eventTargetHasListener(
+            self,
+            typ,
+            capture,
+            cbk.id,
+        );
+        if (lst == null) {
+            return;
+        }
+
+        // remove listener
+        try parser.eventTargetRemoveEventListener(
+            self,
+            typ,
+            lst.?,
+            capture,
+        );
+    }
+
+    pub fn _dispatchEvent(self: *parser.EventTarget, event: *parser.Event) !bool {
+        return try parser.eventTargetDispatchEvent(self, event);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.EventTarget" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "new EventTarget()", "[object EventTarget]" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let content = document.getElementById('content')", "undefined" },
+        .{ "let para = document.getElementById('para')", "undefined" },
+        // NOTE: as some event properties will change during the event dispatching phases
+        // we need to copy thoses values in order to check them afterwards
+        .{
+            \\ var nb = 0; var evt; var phase; var cur;
+            \\ function cbk(event) {
+            \\   evt = event;
+            \\   phase = event.eventPhase;
+            \\   cur = event.currentTarget;
+            \\   nb ++;
+            \\ }
+            ,
+            "undefined",
+        },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "content.addEventListener('basic', cbk)", "undefined" },
+        .{ "content.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "1" },
+        .{ "evt instanceof Event", "true" },
+        .{ "evt.type", "basic" },
+        .{ "phase", "2" },
+        .{ "cur.getAttribute('id')", "content" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; evt = undefined; phase = undefined; cur = undefined", "undefined" },
+        .{ "para.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "0" }, // handler is not called, no capture, not the target, no bubbling
+        .{ "evt === undefined", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb  = 0", "0" },
+        .{ "content.addEventListener('basic', cbk)", "undefined" },
+        .{ "content.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb  = 0", "0" },
+        .{ "content.addEventListener('basic', cbk, true)", "undefined" },
+        .{ "content.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "2" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb  = 0", "0" },
+        .{ "content.removeEventListener('basic', cbk)", "undefined" },
+        .{ "content.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb  = 0", "0" },
+        .{ "content.removeEventListener('basic', cbk, {capture: true})", "undefined" },
+        .{ "content.dispatchEvent(new Event('basic'))", "true" },
+        .{ "nb", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; evt = undefined; phase = undefined; cur = undefined", "undefined" },
+        .{ "content.addEventListener('capture', cbk, true)", "undefined" },
+        .{ "content.dispatchEvent(new Event('capture'))", "true" },
+        .{ "nb", "1" },
+        .{ "evt instanceof Event", "true" },
+        .{ "evt.type", "capture" },
+        .{ "phase", "2" },
+        .{ "cur.getAttribute('id')", "content" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; evt = undefined; phase = undefined; cur = undefined", "undefined" },
+        .{ "para.dispatchEvent(new Event('capture'))", "true" },
+        .{ "nb", "1" },
+        .{ "evt instanceof Event", "true" },
+        .{ "evt.type", "capture" },
+        .{ "phase", "1" },
+        .{ "cur.getAttribute('id')", "content" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; evt = undefined; phase = undefined; cur = undefined", "undefined" },
+        .{ "content.addEventListener('bubbles', cbk)", "undefined" },
+        .{ "content.dispatchEvent(new Event('bubbles', {bubbles: true}))", "true" },
+        .{ "nb", "1" },
+        .{ "evt instanceof Event", "true" },
+        .{ "evt.type", "bubbles" },
+        .{ "evt.bubbles", "true" },
+        .{ "phase", "2" },
+        .{ "cur.getAttribute('id')", "content" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; evt = undefined; phase = undefined; cur = undefined", "undefined" },
+        .{ "para.dispatchEvent(new Event('bubbles', {bubbles: true}))", "true" },
+        .{ "nb", "1" },
+        .{ "evt instanceof Event", "true" },
+        .{ "evt.type", "bubbles" },
+        .{ "phase", "3" },
+        .{ "cur.getAttribute('id')", "content" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const obj1 = {calls: 0, handleEvent: function() { this.calls += 1; } };", null },
+        .{ "content.addEventListener('he', obj1);", null },
+        .{ "content.dispatchEvent(new Event('he'));", null },
+        .{ "obj1.calls", "1" },
+
+        .{ "content.removeEventListener('he', obj1);", null },
+        .{ "content.dispatchEvent(new Event('he'));", null },
+        .{ "obj1.calls", "1" },
+    }, .{});
+
+    // doesn't crash on null receiver
+    try runner.testCases(&.{
+        .{ "content.addEventListener('he2', null);", null },
+        .{ "content.dispatchEvent(new Event('he2'));", null },
+    }, .{});
+}
--- a/src/browser/dom/exceptions.zig
+++ b/src/browser/dom/exceptions.zig
@@ -0,0 +1,264 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const allocPrint = std.fmt.allocPrint;
+
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+// https://webidl.spec.whatwg.org/#idl-DOMException
+pub const DOMException = struct {
+    err: ?parser.DOMError,
+    str: []const u8,
+
+    pub const ErrorSet = parser.DOMError;
+
+    // static attributes
+    pub const _INDEX_SIZE_ERR = 1;
+    pub const _DOMSTRING_SIZE_ERR = 2;
+    pub const _HIERARCHY_REQUEST_ERR = 3;
+    pub const _WRONG_DOCUMENT_ERR = 4;
+    pub const _INVALID_CHARACTER_ERR = 5;
+    pub const _NO_DATA_ALLOWED_ERR = 6;
+    pub const _NO_MODIFICATION_ALLOWED_ERR = 7;
+    pub const _NOT_FOUND_ERR = 8;
+    pub const _NOT_SUPPORTED_ERR = 9;
+    pub const _INUSE_ATTRIBUTE_ERR = 10;
+    pub const _INVALID_STATE_ERR = 11;
+    pub const _SYNTAX_ERR = 12;
+    pub const _INVALID_MODIFICATION_ERR = 13;
+    pub const _NAMESPACE_ERR = 14;
+    pub const _INVALID_ACCESS_ERR = 15;
+    pub const _VALIDATION_ERR = 16;
+    pub const _TYPE_MISMATCH_ERR = 17;
+    pub const _SECURITY_ERR = 18;
+    pub const _NETWORK_ERR = 19;
+    pub const _ABORT_ERR = 20;
+    pub const _URL_MISMATCH_ERR = 21;
+    pub const _QUOTA_EXCEEDED_ERR = 22;
+    pub const _TIMEOUT_ERR = 23;
+    pub const _INVALID_NODE_TYPE_ERR = 24;
+    pub const _DATA_CLONE_ERR = 25;
+
+    pub fn constructor(message_: ?[]const u8, name_: ?[]const u8, page: *const Page) !DOMException {
+        const message = message_ orelse "";
+        const err = if (name_) |n| error_from_str(n) else null;
+        const fixed_name = name(err);
+
+        if (message.len == 0) return .{ .err = err, .str = fixed_name };
+
+        const str = try allocPrint(page.arena, "{s}: {s}", .{ fixed_name, message });
+        return .{ .err = err, .str = str };
+    }
+
+    // TODO: deinit
+    pub fn init(alloc: std.mem.Allocator, err: anyerror, callerName: []const u8) !DOMException {
+        const errCast = @as(parser.DOMError, @errorCast(err));
+        const errName = DOMException.name(errCast);
+        const str = switch (errCast) {
+            error.HierarchyRequest => try allocPrint(
+                alloc,
+                "{s}: Failed to execute '{s}' on 'Node': The new child element contains the parent.",
+                .{ errName, callerName },
+            ),
+            error.NoError => unreachable,
+            else => try allocPrint(
+                alloc,
+                "{s}: TODO message", // TODO: implement other messages
+                .{DOMException.name(errCast)},
+            ),
+        };
+        return .{ .err = errCast, .str = str };
+    }
+
+    fn error_from_str(name_: []const u8) ?parser.DOMError {
+        // @speed: Consider length first, left as is for maintainability, awaiting switch on string support
+        if (std.mem.eql(u8, name_, "IndexSizeError")) return error.IndexSize;
+        if (std.mem.eql(u8, name_, "StringSizeError")) return error.StringSize;
+        if (std.mem.eql(u8, name_, "HierarchyRequestError")) return error.HierarchyRequest;
+        if (std.mem.eql(u8, name_, "WrongDocumentError")) return error.WrongDocument;
+        if (std.mem.eql(u8, name_, "InvalidCharacterError")) return error.InvalidCharacter;
+        if (std.mem.eql(u8, name_, "NoDataAllowedError")) return error.NoDataAllowed;
+        if (std.mem.eql(u8, name_, "NoModificationAllowedError")) return error.NoModificationAllowed;
+        if (std.mem.eql(u8, name_, "NotFoundError")) return error.NotFound;
+        if (std.mem.eql(u8, name_, "NotSupportedError")) return error.NotSupported;
+        if (std.mem.eql(u8, name_, "InuseAttributeError")) return error.InuseAttribute;
+        if (std.mem.eql(u8, name_, "InvalidStateError")) return error.InvalidState;
+        if (std.mem.eql(u8, name_, "SyntaxError")) return error.Syntax;
+        if (std.mem.eql(u8, name_, "InvalidModificationError")) return error.InvalidModification;
+        if (std.mem.eql(u8, name_, "NamespaceError")) return error.Namespace;
+        if (std.mem.eql(u8, name_, "InvalidAccessError")) return error.InvalidAccess;
+        if (std.mem.eql(u8, name_, "ValidationError")) return error.Validation;
+        if (std.mem.eql(u8, name_, "TypeMismatchError")) return error.TypeMismatch;
+        if (std.mem.eql(u8, name_, "SecurityError")) return error.Security;
+        if (std.mem.eql(u8, name_, "NetworkError")) return error.Network;
+        if (std.mem.eql(u8, name_, "AbortError")) return error.Abort;
+        if (std.mem.eql(u8, name_, "URLismatchError")) return error.URLismatch;
+        if (std.mem.eql(u8, name_, "QuotaExceededError")) return error.QuotaExceeded;
+        if (std.mem.eql(u8, name_, "TimeoutError")) return error.Timeout;
+        if (std.mem.eql(u8, name_, "InvalidNodeTypeError")) return error.InvalidNodeType;
+        if (std.mem.eql(u8, name_, "DataCloneError")) return error.DataClone;
+
+        // custom netsurf error
+        if (std.mem.eql(u8, name_, "UnspecifiedEventTypeError")) return error.UnspecifiedEventType;
+        if (std.mem.eql(u8, name_, "DispatchRequestError")) return error.DispatchRequest;
+        if (std.mem.eql(u8, name_, "NoMemoryError")) return error.NoMemory;
+        if (std.mem.eql(u8, name_, "AttributeWrongTypeError")) return error.AttributeWrongType;
+        return null;
+    }
+
+    fn name(err_: ?parser.DOMError) []const u8 {
+        const err = err_ orelse return "Error";
+
+        return switch (err) {
+            error.IndexSize => "IndexSizeError",
+            error.StringSize => "StringSizeError", // Legacy: DOMSTRING_SIZE_ERR
+            error.HierarchyRequest => "HierarchyRequestError",
+            error.WrongDocument => "WrongDocumentError",
+            error.InvalidCharacter => "InvalidCharacterError",
+            error.NoDataAllowed => "NoDataAllowedError", // Legacy: NO_DATA_ALLOWED_ERR
+            error.NoModificationAllowed => "NoModificationAllowedError",
+            error.NotFound => "NotFoundError",
+            error.NotSupported => "NotSupportedError",
+            error.InuseAttribute => "InuseAttributeError",
+            error.InvalidState => "InvalidStateError",
+            error.Syntax => "SyntaxError",
+            error.InvalidModification => "InvalidModificationError",
+            error.Namespace => "NamespaceError",
+            error.InvalidAccess => "InvalidAccessError",
+            error.Validation => "ValidationError", // Legacy: VALIDATION_ERR
+            error.TypeMismatch => "TypeMismatchError",
+            error.Security => "SecurityError",
+            error.Network => "NetworkError",
+            error.Abort => "AbortError",
+            error.URLismatch => "URLismatchError",
+            error.QuotaExceeded => "QuotaExceededError",
+            error.Timeout => "TimeoutError",
+            error.InvalidNodeType => "InvalidNodeTypeError",
+            error.DataClone => "DataCloneError",
+            error.NoError => unreachable,
+
+            // custom netsurf error
+            error.UnspecifiedEventType => "UnspecifiedEventTypeError",
+            error.DispatchRequest => "DispatchRequestError",
+            error.NoMemory => "NoMemoryError",
+            error.AttributeWrongType => "AttributeWrongTypeError",
+        };
+    }
+
+    // JS properties and methods
+
+    pub fn get_code(self: *const DOMException) u8 {
+        const err = self.err orelse return 0;
+        return switch (err) {
+            error.IndexSize => 1,
+            error.StringSize => 2,
+            error.HierarchyRequest => 3,
+            error.WrongDocument => 4,
+            error.InvalidCharacter => 5,
+            error.NoDataAllowed => 6,
+            error.NoModificationAllowed => 7,
+            error.NotFound => 8,
+            error.NotSupported => 9,
+            error.InuseAttribute => 10,
+            error.InvalidState => 11,
+            error.Syntax => 12,
+            error.InvalidModification => 13,
+            error.Namespace => 14,
+            error.InvalidAccess => 15,
+            error.Validation => 16,
+            error.TypeMismatch => 17,
+            error.Security => 18,
+            error.Network => 19,
+            error.Abort => 20,
+            error.URLismatch => 21,
+            error.QuotaExceeded => 22,
+            error.Timeout => 23,
+            error.InvalidNodeType => 24,
+            error.DataClone => 25,
+            error.NoError => unreachable,
+
+            // custom netsurf error
+            error.UnspecifiedEventType => 128,
+            error.DispatchRequest => 129,
+            error.NoMemory => 130,
+            error.AttributeWrongType => 131,
+        };
+    }
+
+    pub fn get_name(self: *const DOMException) []const u8 {
+        return DOMException.name(self.err);
+    }
+
+    pub fn get_message(self: *const DOMException) []const u8 {
+        const errName = DOMException.name(self.err);
+        if (self.str.len <= errName.len + 2) return "";
+        return self.str[errName.len + 2 ..]; // ! Requires str is formatted as "{name}: {message}"
+    }
+
+    pub fn _toString(self: *const DOMException) []const u8 {
+        return self.str;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Exception" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    const err = "Failed to execute 'appendChild' on 'Node': The new child element contains the parent.";
+    try runner.testCases(&.{
+        .{ "let content = document.getElementById('content')", "undefined" },
+        .{ "let link = document.getElementById('link')", "undefined" },
+        // HierarchyRequestError
+        .{
+            \\ var he;
+            \\ try { link.appendChild(content) } catch (error) { he = error}
+            \\ he.name
+            ,
+            "HierarchyRequestError",
+        },
+        .{ "he.code", "3" },
+        .{ "he.message", err },
+        .{ "he.toString()", "HierarchyRequestError: " ++ err },
+        .{ "he instanceof DOMException", "true" },
+        .{ "he instanceof Error", "true" },
+    }, .{});
+
+    // Test DOMException constructor
+    try runner.testCases(&.{
+        .{ "let exc0 = new DOMException()", "undefined" },
+        .{ "exc0.name", "Error" },
+        .{ "exc0.code", "0" },
+        .{ "exc0.message", "" },
+        .{ "exc0.toString()", "Error" },
+
+        .{ "let exc1 = new DOMException('Sandwich malfunction')", "undefined" },
+        .{ "exc1.name", "Error" },
+        .{ "exc1.code", "0" },
+        .{ "exc1.message", "Sandwich malfunction" },
+        .{ "exc1.toString()", "Error: Sandwich malfunction" },
+
+        .{ "let exc2 = new DOMException('Caterpillar turned into a butterfly', 'NoModificationAllowedError')", "undefined" },
+        .{ "exc2.name", "NoModificationAllowedError" },
+        .{ "exc2.code", "7" },
+        .{ "exc2.message", "Caterpillar turned into a butterfly" },
+        .{ "exc2.toString()", "NoModificationAllowedError: Caterpillar turned into a butterfly" },
+    }, .{});
+}
--- a/src/browser/dom/html_collection.zig
+++ b/src/browser/dom/html_collection.zig
@@ -0,0 +1,500 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const parser = @import("../netsurf.zig");
+
+const Element = @import("element.zig").Element;
+const Union = @import("element.zig").Union;
+const JsThis = @import("../env.zig").JsThis;
+const Walker = @import("walker.zig").Walker;
+
+const Matcher = union(enum) {
+    matchByName: MatchByName,
+    matchByTagName: MatchByTagName,
+    matchByClassName: MatchByClassName,
+    matchByLinks: MatchByLinks,
+    matchByAnchors: MatchByAnchors,
+    matchTrue: struct {},
+    matchFalse: struct {},
+
+    pub fn match(self: Matcher, node: *parser.Node) !bool {
+        switch (self) {
+            .matchTrue => return true,
+            .matchFalse => return false,
+            .matchByLinks => return MatchByLinks.match(node),
+            .matchByAnchors => return MatchByAnchors.match(node),
+            inline else => |m| return m.match(node),
+        }
+    }
+};
+
+pub const MatchByTagName = struct {
+    // tag is used to select node against their name.
+    // tag comparison is case insensitive.
+    tag: []const u8,
+    is_wildcard: bool,
+
+    fn init(arena: Allocator, tag_name: []const u8) !MatchByTagName {
+        if (std.mem.eql(u8, tag_name, "*")) {
+            return .{ .tag = "*", .is_wildcard = true };
+        }
+
+        return .{
+            .tag = try arena.dupe(u8, tag_name),
+            .is_wildcard = false,
+        };
+    }
+
+    pub fn match(self: MatchByTagName, node: *parser.Node) !bool {
+        return self.is_wildcard or std.ascii.eqlIgnoreCase(self.tag, try parser.nodeName(node));
+    }
+};
+
+pub fn HTMLCollectionByTagName(
+    arena: Allocator,
+    root: ?*parser.Node,
+    tag_name: []const u8,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerDepthFirst = .{} },
+        .matcher = .{ .matchByTagName = try MatchByTagName.init(arena, tag_name) },
+        .include_root = include_root,
+    };
+}
+
+pub const MatchByClassName = struct {
+    class_names: []const u8,
+
+    fn init(arena: Allocator, class_names: []const u8) !MatchByClassName {
+        return .{
+            .class_names = try arena.dupe(u8, class_names),
+        };
+    }
+
+    pub fn match(self: MatchByClassName, node: *parser.Node) !bool {
+        const e = parser.nodeToElement(node);
+
+        var it = std.mem.splitScalar(u8, self.class_names, ' ');
+        while (it.next()) |c| {
+            if (!try parser.elementHasClass(e, c)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+};
+
+pub fn HTMLCollectionByClassName(
+    arena: Allocator,
+    root: ?*parser.Node,
+    classNames: []const u8,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerDepthFirst = .{} },
+        .matcher = .{ .matchByClassName = try MatchByClassName.init(arena, classNames) },
+        .include_root = include_root,
+    };
+}
+
+pub const MatchByName = struct {
+    name: []const u8,
+
+    fn init(arena: Allocator, name: []const u8) !MatchByName {
+        return .{
+            .name = try arena.dupe(u8, name),
+        };
+    }
+
+    pub fn match(self: MatchByName, node: *parser.Node) !bool {
+        const e = parser.nodeToElement(node);
+        const nname = try parser.elementGetAttribute(e, "name") orelse return false;
+        return std.mem.eql(u8, self.name, nname);
+    }
+};
+
+pub fn HTMLCollectionByName(
+    arena: Allocator,
+    root: ?*parser.Node,
+    name: []const u8,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerDepthFirst = .{} },
+        .matcher = .{ .matchByName = try MatchByName.init(arena, name) },
+        .include_root = include_root,
+    };
+}
+
+// HTMLAllCollection is a special type: instances of it are falsy. It's the only
+// object in the WebAPI that behaves like this - in fact, it's even a special
+// case in the JavaScript spec.
+// This is important, because a lot of browser detection rely on this behavior
+// to determine what browser is running.
+
+// It's also possible to use an instance like a function:
+//   document.all(3)
+//   document.all('some_id')
+pub const HTMLAllCollection = struct {
+    pub const prototype = *HTMLCollection;
+
+    proto: HTMLCollection,
+
+    pub const mark_as_undetectable = true;
+
+    pub fn init(root: ?*parser.Node) HTMLAllCollection {
+        return .{ .proto = .{
+            .root = root,
+            .walker = .{ .walkerDepthFirst = .{} },
+            .matcher = .{ .matchTrue = .{} },
+            .include_root = true,
+        } };
+    }
+
+    const CAllAsFunctionArg = union(enum) {
+        index: u32,
+        id: []const u8,
+    };
+
+    pub fn jsCallAsFunction(self: *HTMLAllCollection, arg: CAllAsFunctionArg) !?Union {
+        return switch (arg) {
+            .index => |i| self.proto._item(i),
+            .id => |id| self.proto._namedItem(id),
+        };
+    }
+};
+
+pub fn HTMLCollectionChildren(
+    root: ?*parser.Node,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerChildren = .{} },
+        .matcher = .{ .matchTrue = .{} },
+        .include_root = include_root,
+    };
+}
+
+pub fn HTMLCollectionEmpty() !HTMLCollection {
+    return HTMLCollection{
+        .root = null,
+        .walker = .{ .walkerNone = .{} },
+        .matcher = .{ .matchFalse = .{} },
+        .include_root = false,
+    };
+}
+
+// MatchByLinks matches the a and area elements in the Document that have href
+// attributes.
+// https://html.spec.whatwg.org/#dom-document-links
+pub const MatchByLinks = struct {
+    pub fn match(node: *parser.Node) !bool {
+        const tag = try parser.nodeName(node);
+        if (!std.ascii.eqlIgnoreCase(tag, "a") and !std.ascii.eqlIgnoreCase(tag, "area")) {
+            return false;
+        }
+        const elem = @as(*parser.Element, @ptrCast(node));
+        return parser.elementHasAttribute(elem, "href");
+    }
+};
+
+pub fn HTMLCollectionByLinks(
+    root: ?*parser.Node,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerDepthFirst = .{} },
+        .matcher = .{ .matchByLinks = MatchByLinks{} },
+        .include_root = include_root,
+    };
+}
+
+// MatchByAnchors matches the a elements in the Document that have name
+// attributes.
+// https://html.spec.whatwg.org/#dom-document-anchors
+pub const MatchByAnchors = struct {
+    pub fn match(node: *parser.Node) !bool {
+        const tag = try parser.nodeName(node);
+        if (!std.ascii.eqlIgnoreCase(tag, "a")) return false;
+
+        const elem = @as(*parser.Element, @ptrCast(node));
+        return parser.elementHasAttribute(elem, "name");
+    }
+};
+
+pub fn HTMLCollectionByAnchors(
+    root: ?*parser.Node,
+    include_root: bool,
+) !HTMLCollection {
+    return HTMLCollection{
+        .root = root,
+        .walker = .{ .walkerDepthFirst = .{} },
+        .matcher = .{ .matchByAnchors = MatchByAnchors{} },
+        .include_root = include_root,
+    };
+}
+
+pub const HTMLCollectionIterator = struct {
+    coll: *HTMLCollection,
+    index: u32 = 0,
+
+    pub const Return = struct {
+        value: ?Union,
+        done: bool,
+    };
+
+    pub fn _next(self: *HTMLCollectionIterator) !Return {
+        const e = try self.coll._item(self.index);
+        if (e == null) {
+            return Return{
+                .value = null,
+                .done = true,
+            };
+        }
+
+        self.index += 1;
+        return Return{
+            .value = e,
+            .done = false,
+        };
+    }
+};
+
+// WEB IDL https://dom.spec.whatwg.org/#htmlcollection
+// HTMLCollection is re implemented in zig here because libdom
+// dom_html_collection expects a comparison function callback as arguement.
+// But we wanted a dynamically comparison here, according to the match tagname.
+pub const HTMLCollection = struct {
+    matcher: Matcher,
+    walker: Walker,
+
+    root: ?*parser.Node,
+
+    // By default the HTMLCollection walk on the root's descendant only.
+    // But on somes cases, like for dom document, we want to walk over the root
+    // itself.
+    include_root: bool = false,
+
+    // save a state for the collection to improve the _item speed.
+    cur_idx: ?u32 = null,
+    cur_node: ?*parser.Node = null,
+
+    // start returns the first node to walk on.
+    fn start(self: *const HTMLCollection) !?*parser.Node {
+        if (self.root == null) return null;
+
+        if (self.include_root) {
+            return self.root.?;
+        }
+
+        return try self.walker.get_next(self.root.?, null);
+    }
+
+    pub fn _symbol_iterator(self: *HTMLCollection) HTMLCollectionIterator {
+        return HTMLCollectionIterator{
+            .coll = self,
+        };
+    }
+
+    /// get_length computes the collection's length dynamically according to
+    /// the current root structure.
+    // TODO: nodes retrieved must be de-referenced.
+    pub fn get_length(self: *HTMLCollection) !u32 {
+        if (self.root == null) return 0;
+
+        var len: u32 = 0;
+        var node = try self.start() orelse return 0;
+
+        while (true) {
+            if (try parser.nodeType(node) == .element) {
+                if (try self.matcher.match(node)) {
+                    len += 1;
+                }
+            }
+
+            node = try self.walker.get_next(self.root.?, node) orelse break;
+        }
+
+        return len;
+    }
+
+    pub fn item(self: *HTMLCollection, index: u32) !?*parser.Node {
+        if (self.root == null) return null;
+
+        var i: u32 = 0;
+        var node: *parser.Node = undefined;
+
+        // Use the current state to improve speed if possible.
+        if (self.cur_idx != null and index >= self.cur_idx.?) {
+            i = self.cur_idx.?;
+            node = self.cur_node.?;
+        } else {
+            node = try self.start() orelse return null;
+        }
+
+        while (true) {
+            if (try parser.nodeType(node) == .element) {
+                if (try self.matcher.match(node)) {
+                    // check if we found the searched element.
+                    if (i == index) {
+                        // save the current state
+                        self.cur_node = node;
+                        self.cur_idx = i;
+
+                        return node;
+                    }
+
+                    i += 1;
+                }
+            }
+
+            node = try self.walker.get_next(self.root.?, node) orelse break;
+        }
+
+        return null;
+    }
+
+    pub fn _item(self: *HTMLCollection, index: u32) !?Union {
+        const node = try self.item(index) orelse return null;
+        const e = @as(*parser.Element, @ptrCast(node));
+        return try Element.toInterface(e);
+    }
+
+    pub fn _namedItem(self: *const HTMLCollection, name: []const u8) !?Union {
+        if (self.root == null) return null;
+        if (name.len == 0) return null;
+
+        var node = try self.start() orelse return null;
+
+        while (true) {
+            if (try parser.nodeType(node) == .element) {
+                if (try self.matcher.match(node)) {
+                    const elem = @as(*parser.Element, @ptrCast(node));
+
+                    var attr = try parser.elementGetAttribute(elem, "id");
+                    // check if the node id corresponds to the name argument.
+                    if (attr != null and std.mem.eql(u8, name, attr.?)) {
+                        return try Element.toInterface(elem);
+                    }
+
+                    attr = try parser.elementGetAttribute(elem, "name");
+                    // check if the node id corresponds to the name argument.
+                    if (attr != null and std.mem.eql(u8, name, attr.?)) {
+                        return try Element.toInterface(elem);
+                    }
+                }
+            }
+
+            node = try self.walker.get_next(self.root.?, node) orelse break;
+        }
+
+        return null;
+    }
+
+    fn item_name(elt: *parser.Element) !?[]const u8 {
+        if (try parser.elementGetAttribute(elt, "id")) |v| {
+            return v;
+        }
+        if (try parser.elementGetAttribute(elt, "name")) |v| {
+            return v;
+        }
+
+        return null;
+    }
+
+    pub fn postAttach(self: *HTMLCollection, js_this: JsThis) !void {
+        const len = try self.get_length();
+        for (0..len) |i| {
+            const node = try self.item(@intCast(i)) orelse unreachable;
+            const e = @as(*parser.Element, @ptrCast(node));
+            const as_interface = try Element.toInterface(e);
+            try js_this.setIndex(@intCast(i), as_interface, .{});
+
+            if (try item_name(e)) |name| {
+                // Even though an entry might have an empty id, the spec says
+                // that namedItem("") should always return null
+                if (name.len > 0) {
+                    // Named fields should not be enumerable (it is defined with
+                    // the LegacyUnenumerableNamedProperties flag.)
+                    try js_this.set(name, as_interface, .{ .DONT_ENUM = true });
+                }
+            }
+        }
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.HTMLCollection" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let getElementsByTagName = document.getElementsByTagName('p')", "undefined" },
+        .{ "getElementsByTagName.length", "2" },
+        .{ "let getElementsByTagNameCI = document.getElementsByTagName('P')", "undefined" },
+        .{ "getElementsByTagNameCI.length", "2" },
+        .{ "getElementsByTagName.item(0).localName", "p" },
+        .{ "getElementsByTagName.item(1).localName", "p" },
+        .{ "let getElementsByTagNameAll = document.getElementsByTagName('*')", "undefined" },
+        .{ "getElementsByTagNameAll.length", "8" },
+        .{ "getElementsByTagNameAll.item(0).localName", "html" },
+        .{ "getElementsByTagNameAll.item(0).localName", "html" },
+        .{ "getElementsByTagNameAll.item(1).localName", "head" },
+        .{ "getElementsByTagNameAll.item(0).localName", "html" },
+        .{ "getElementsByTagNameAll.item(2).localName", "body" },
+        .{ "getElementsByTagNameAll.item(3).localName", "div" },
+        .{ "getElementsByTagNameAll.item(7).localName", "p" },
+        .{ "getElementsByTagNameAll.namedItem('para-empty-child').localName", "span" },
+
+        // array like
+        .{ "getElementsByTagNameAll[0].localName", "html" },
+        .{ "getElementsByTagNameAll[7].localName", "p" },
+        .{ "getElementsByTagNameAll[8]", "undefined" },
+        .{ "getElementsByTagNameAll['para-empty-child'].localName", "span" },
+        .{ "getElementsByTagNameAll['foo']", "undefined" },
+
+        .{ "document.getElementById('content').getElementsByTagName('*').length", "4" },
+        .{ "document.getElementById('content').getElementsByTagName('p').length", "2" },
+        .{ "document.getElementById('content').getElementsByTagName('div').length", "0" },
+
+        .{ "document.children.length", "1" },
+        .{ "document.getElementById('content').children.length", "3" },
+
+        // check liveness
+        .{ "let content = document.getElementById('content')", "undefined" },
+        .{ "let pe = document.getElementById('para-empty')", "undefined" },
+        .{ "let p = document.createElement('p')", "undefined" },
+        .{ "p.textContent = 'OK live'", "OK live" },
+        .{ "getElementsByTagName.item(1).textContent", " And" },
+        .{ "content.appendChild(p) != undefined", "true" },
+        .{ "getElementsByTagName.length", "3" },
+        .{ "getElementsByTagName.item(2).textContent", "OK live" },
+        .{ "content.insertBefore(p, pe) != undefined", "true" },
+        .{ "getElementsByTagName.item(0).textContent", "OK live" },
+    }, .{});
+}
--- a/src/browser/dom/implementation.zig
+++ b/src/browser/dom/implementation.zig
@@ -0,0 +1,72 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+const DOMException = @import("exceptions.zig").DOMException;
+
+// WEB IDL https://dom.spec.whatwg.org/#domimplementation
+pub const DOMImplementation = struct {
+    pub const Exception = DOMException;
+
+    pub fn _createDocumentType(
+        _: *DOMImplementation,
+        qname: [:0]const u8,
+        publicId: [:0]const u8,
+        systemId: [:0]const u8,
+    ) !*parser.DocumentType {
+        return try parser.domImplementationCreateDocumentType(qname, publicId, systemId);
+    }
+
+    pub fn _createDocument(
+        _: *DOMImplementation,
+        namespace: ?[:0]const u8,
+        qname: ?[:0]const u8,
+        doctype: ?*parser.DocumentType,
+    ) !*parser.Document {
+        return try parser.domImplementationCreateDocument(namespace, qname, doctype);
+    }
+
+    pub fn _createHTMLDocument(_: *DOMImplementation, title: ?[]const u8) !*parser.DocumentHTML {
+        return try parser.domImplementationCreateHTMLDocument(title);
+    }
+
+    pub fn _hasFeature(_: *DOMImplementation) bool {
+        return true;
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Implementation" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let impl = document.implementation", "undefined" },
+        .{ "impl.createHTMLDocument();", "[object HTMLDocument]" },
+        .{ "const doc = impl.createHTMLDocument('foo');", "undefined" },
+        .{ "doc", "[object HTMLDocument]" },
+        .{ "doc.title", "foo" },
+        .{ "doc.body", "[object HTMLBodyElement]" },
+        .{ "impl.createDocument(null, 'foo');", "[object Document]" },
+        .{ "impl.createDocumentType('foo', 'bar', 'baz')", "[object DocumentType]" },
+        .{ "impl.hasFeature()", "true" },
+    }, .{});
+}
--- a/src/browser/dom/intersection_observer.zig
+++ b/src/browser/dom/intersection_observer.zig
@@ -0,0 +1,290 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const Env = @import("../env.zig").Env;
+const Element = @import("element.zig").Element;
+
+pub const Interfaces = .{
+    IntersectionObserver,
+    IntersectionObserverEntry,
+};
+
+// This is supposed to listen to change between the root and observation targets.
+// However, our rendered stores everything as 1 pixel sized boxes in a long row that never changes.
+// As such, there are no changes to intersections between the root and any target.
+// Instead we keep a list of all entries that are being observed.
+// The callback is called with all entries everytime a new entry is added(observed).
+// Potentially we should also call the callback at a regular interval.
+// The returned Entries are phony, they always indicate full intersection.
+// https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserver
+pub const IntersectionObserver = struct {
+    page: *Page,
+    callback: Env.Function,
+    options: IntersectionObserverOptions,
+
+    observed_entries: std.ArrayListUnmanaged(IntersectionObserverEntry),
+
+    // new IntersectionObserver(callback)
+    // new IntersectionObserver(callback, options) [not supported yet]
+    pub fn constructor(callback: Env.Function, options_: ?IntersectionObserverOptions, page: *Page) !IntersectionObserver {
+        var options = IntersectionObserverOptions{
+            .root = parser.documentToNode(parser.documentHTMLToDocument(page.window.document)),
+            .rootMargin = "0px 0px 0px 0px",
+            .threshold = .{ .single = 0.0 },
+        };
+        if (options_) |*o| {
+            if (o.root) |root| {
+                options.root = root;
+            } // Other properties are not used due to the way we render
+        }
+
+        return .{
+            .page = page,
+            .callback = callback,
+            .options = options,
+            .observed_entries = .{},
+        };
+    }
+
+    pub fn _disconnect(self: *IntersectionObserver) !void {
+        self.observed_entries = .{}; // We don't free as it is on an arena
+    }
+
+    pub fn _observe(self: *IntersectionObserver, target_element: *parser.Element) !void {
+        for (self.observed_entries.items) |*observer| {
+            if (observer.target == target_element) {
+                return; // Already observed
+            }
+        }
+
+        try self.observed_entries.append(self.page.arena, .{
+            .page = self.page,
+            .target = target_element,
+            .options = &self.options,
+        });
+
+        var result: Env.Function.Result = undefined;
+        self.callback.tryCall(void, .{self.observed_entries.items}, &result) catch {
+            log.debug(.user_script, "callback error", .{
+                .err = result.exception,
+                .stack = result.stack,
+                .source = "intersection observer",
+            });
+        };
+    }
+
+    pub fn _unobserve(self: *IntersectionObserver, target: *parser.Element) !void {
+        for (self.observed_entries.items, 0..) |*observer, index| {
+            if (observer.target == target) {
+                _ = self.observed_entries.swapRemove(index);
+                break;
+            }
+        }
+    }
+
+    pub fn _takeRecords(self: *IntersectionObserver) []IntersectionObserverEntry {
+        return self.observed_entries.items;
+    }
+};
+
+const IntersectionObserverOptions = struct {
+    root: ?*parser.Node, // Element or Document
+    rootMargin: ?[]const u8,
+    threshold: ?Threshold,
+
+    const Threshold = union(enum) {
+        single: f32,
+        list: []const f32,
+    };
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/IntersectionObserverEntry
+// https://w3c.github.io/IntersectionObserver/#intersection-observer-entry
+pub const IntersectionObserverEntry = struct {
+    page: *Page,
+    target: *parser.Element,
+    options: *IntersectionObserverOptions,
+
+    // Returns the bounds rectangle of the target element as a DOMRectReadOnly. The bounds are computed as described in the documentation for Element.getBoundingClientRect().
+    pub fn get_boundingClientRect(self: *const IntersectionObserverEntry) !Element.DOMRect {
+        return Element._getBoundingClientRect(self.target, self.page);
+    }
+
+    // Returns the ratio of the intersectionRect to the boundingClientRect.
+    pub fn get_intersectionRatio(_: *const IntersectionObserverEntry) f32 {
+        return 1.0;
+    }
+
+    // Returns a DOMRectReadOnly representing the target's visible area.
+    pub fn get_intersectionRect(self: *const IntersectionObserverEntry) !Element.DOMRect {
+        return Element._getBoundingClientRect(self.target, self.page);
+    }
+
+    // A Boolean value which is true if the target element intersects with the
+    // intersection observer's root. If this is true, then, the
+    // IntersectionObserverEntry describes a transition into a state of
+    // intersection; if it's false, then you know the transition is from
+    // intersecting to not-intersecting.
+    pub fn get_isIntersecting(_: *const IntersectionObserverEntry) bool {
+        return true;
+    }
+
+    // Returns a DOMRectReadOnly for the intersection observer's root.
+    pub fn get_rootBounds(self: *const IntersectionObserverEntry) !Element.DOMRect {
+        const root = self.options.root.?;
+        if (@intFromPtr(root) == @intFromPtr(self.page.window.document)) {
+            return self.page.renderer.boundingRect();
+        }
+
+        const root_type = try parser.nodeType(root);
+
+        var element: *parser.Element = undefined;
+        switch (root_type) {
+            .element => element = parser.nodeToElement(root),
+            .document => {
+                const doc = parser.nodeToDocument(root);
+                element = (try parser.documentGetDocumentElement(doc)).?;
+            },
+            else => return error.InvalidState,
+        }
+
+        return Element._getBoundingClientRect(element, self.page);
+    }
+
+    // The Element whose intersection with the root changed.
+    pub fn get_target(self: *const IntersectionObserverEntry) *parser.Element {
+        return self.target;
+    }
+
+    // TODO: pub fn get_time(self: *const IntersectionObserverEntry)
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.IntersectionObserver" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "new IntersectionObserver(() => {}).observe(document.documentElement);", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let count_a = 0;", "undefined" },
+        .{ "const a1 = document.createElement('div');", "undefined" },
+        .{ "new IntersectionObserver(entries => {count_a += 1;}).observe(a1);", "undefined" },
+        .{ "count_a;", "1" },
+    }, .{});
+
+    // This test is documenting current behavior, not correct behavior.
+    // Currently every time observe is called, the callback is called with all entries.
+    try runner.testCases(&.{
+        .{ "let count_b = 0;", "undefined" },
+        .{ "let observer_b = new IntersectionObserver(entries => {count_b = entries.length;});", "undefined" },
+        .{ "const b1 = document.createElement('div');", "undefined" },
+        .{ "observer_b.observe(b1);", "undefined" },
+        .{ "count_b;", "1" },
+        .{ "const b2 = document.createElement('div');", "undefined" },
+        .{ "observer_b.observe(b2);", "undefined" },
+        .{ "count_b;", "2" },
+    }, .{});
+
+    // Re-observing is a no-op
+    try runner.testCases(&.{
+        .{ "let count_bb = 0;", "undefined" },
+        .{ "let observer_bb = new IntersectionObserver(entries => {count_bb = entries.length;});", "undefined" },
+        .{ "const bb1 = document.createElement('div');", "undefined" },
+        .{ "observer_bb.observe(bb1);", "undefined" },
+        .{ "count_bb;", "1" },
+        .{ "observer_bb.observe(bb1);", "undefined" },
+        .{ "count_bb;", "1" }, // Still 1, not 2
+    }, .{});
+
+    // Unobserve
+    try runner.testCases(&.{
+        .{ "let count_c = 0;", "undefined" },
+        .{ "let observer_c = new IntersectionObserver(entries => { count_c = entries.length;});", "undefined" },
+        .{ "const c1 = document.createElement('div');", "undefined" },
+        .{ "observer_c.observe(c1);", "undefined" },
+        .{ "count_c;", "1" },
+        .{ "observer_c.unobserve(c1);", "undefined" },
+        .{ "const c2 = document.createElement('div');", "undefined" },
+        .{ "observer_c.observe(c2);", "undefined" },
+        .{ "count_c;", "1" },
+    }, .{});
+
+    // Disconnect
+    try runner.testCases(&.{
+        .{ "let observer_d = new IntersectionObserver(entries => {});", "undefined" },
+        .{ "let d1 = document.createElement('div');", "undefined" },
+        .{ "observer_d.observe(d1);", "undefined" },
+        .{ "observer_d.disconnect();", "undefined" },
+        .{ "observer_d.takeRecords().length;", "0" },
+    }, .{});
+
+    // takeRecords
+    try runner.testCases(&.{
+        .{ "let observer_e = new IntersectionObserver(entries => {});", "undefined" },
+        .{ "let e1 = document.createElement('div');", "undefined" },
+        .{ "observer_e.observe(e1);", "undefined" },
+        .{ "const e2 = document.createElement('div');", "undefined" },
+        .{ "observer_e.observe(e2);", "undefined" },
+        .{ "observer_e.takeRecords().length;", "2" },
+    }, .{});
+
+    // Entry
+    try runner.testCases(&.{
+        .{ "let entry;", "undefined" },
+        .{ "let div1 = document.createElement('div')", null },
+        .{ "document.body.appendChild(div1);", null },
+        .{ "new IntersectionObserver(entries => { entry = entries[0]; }).observe(div1);", null },
+        .{ "entry.boundingClientRect.x;", "0" },
+        .{ "entry.intersectionRatio;", "1" },
+        .{ "entry.intersectionRect.x;", "0" },
+        .{ "entry.intersectionRect.y;", "0" },
+        .{ "entry.intersectionRect.width;", "1" },
+        .{ "entry.intersectionRect.height;", "1" },
+        .{ "entry.isIntersecting;", "true" },
+        .{ "entry.rootBounds.x;", "0" },
+        .{ "entry.rootBounds.y;", "0" },
+        .{ "entry.rootBounds.width;", "1" },
+        .{ "entry.rootBounds.height;", "1" },
+        .{ "entry.target;", "[object HTMLDivElement]" },
+    }, .{});
+
+    // Options
+    try runner.testCases(&.{
+        .{ "const new_root = document.createElement('span');", null },
+        .{ "document.body.appendChild(new_root);", null },
+        .{ "let new_entry;", "undefined" },
+        .{
+            \\ const new_observer = new IntersectionObserver(
+            \\ entries => { new_entry = entries[0]; },
+            \\ {root: new_root, rootMargin: '0px 0px 0px 0px', threshold: [0]});
+            ,
+            "undefined",
+        },
+        .{ "new_observer.observe(document.createElement('div'));", "undefined" },
+        .{ "new_entry.rootBounds.x;", "1" },
+    }, .{});
+}
--- a/src/browser/dom/mutation_observer.zig
+++ b/src/browser/dom/mutation_observer.zig
@@ -0,0 +1,436 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+const Loop = @import("../../runtime/loop.zig").Loop;
+
+const Env = @import("../env.zig").Env;
+const NodeList = @import("nodelist.zig").NodeList;
+
+pub const Interfaces = .{
+    MutationObserver,
+    MutationRecord,
+};
+
+const Walker = @import("../dom/walker.zig").WalkerChildren;
+
+// WEB IDL https://dom.spec.whatwg.org/#interface-mutationobserver
+pub const MutationObserver = struct {
+    loop: *Loop,
+    cbk: Env.Function,
+    arena: Allocator,
+    connected: bool,
+    scheduled: bool,
+    loop_node: Loop.CallbackNode,
+
+    // List of records which were observed. When the call scope ends, we need to
+    // execute our callback with it.
+    observed: std.ArrayListUnmanaged(MutationRecord),
+
+    pub fn constructor(cbk: Env.Function, page: *Page) !MutationObserver {
+        return .{
+            .cbk = cbk,
+            .loop = page.loop,
+            .observed = .{},
+            .connected = true,
+            .scheduled = false,
+            .arena = page.arena,
+            .loop_node = .{ .func = callback },
+        };
+    }
+
+    pub fn _observe(self: *MutationObserver, node: *parser.Node, options_: ?Options) !void {
+        const arena = self.arena;
+        var options = options_ orelse Options{};
+        if (options.attributeFilter.len > 0) {
+            options.attributeFilter = try arena.dupe([]const u8, options.attributeFilter);
+        }
+
+        const observer = try arena.create(Observer);
+        observer.* = .{
+            .node = node,
+            .options = options,
+            .mutation_observer = self,
+            .event_node = .{ .id = self.cbk.id, .func = Observer.handle },
+        };
+
+        // register node's events
+        if (options.childList or options.subtree) {
+            _ = try parser.eventTargetAddEventListener(
+                parser.toEventTarget(parser.Node, node),
+                "DOMNodeInserted",
+                &observer.event_node,
+                false,
+            );
+            _ = try parser.eventTargetAddEventListener(
+                parser.toEventTarget(parser.Node, node),
+                "DOMNodeRemoved",
+                &observer.event_node,
+                false,
+            );
+        }
+        if (options.attr()) {
+            _ = try parser.eventTargetAddEventListener(
+                parser.toEventTarget(parser.Node, node),
+                "DOMAttrModified",
+                &observer.event_node,
+                false,
+            );
+        }
+        if (options.cdata()) {
+            _ = try parser.eventTargetAddEventListener(
+                parser.toEventTarget(parser.Node, node),
+                "DOMCharacterDataModified",
+                &observer.event_node,
+                false,
+            );
+        }
+        if (options.subtree) {
+            _ = try parser.eventTargetAddEventListener(
+                parser.toEventTarget(parser.Node, node),
+                "DOMSubtreeModified",
+                &observer.event_node,
+                false,
+            );
+        }
+    }
+
+    fn callback(node: *Loop.CallbackNode, _: *?u63) void {
+        const self: *MutationObserver = @fieldParentPtr("loop_node", node);
+        if (self.connected == false) {
+            self.scheduled = true;
+            return;
+        }
+        self.scheduled = false;
+
+        const records = self.observed.items;
+        if (records.len == 0) {
+            return;
+        }
+
+        defer self.observed.clearRetainingCapacity();
+
+        var result: Env.Function.Result = undefined;
+        self.cbk.tryCall(void, .{records}, &result) catch {
+            log.debug(.user_script, "callback error", .{
+                .err = result.exception,
+                .stack = result.stack,
+                .source = "mutation observer",
+            });
+        };
+    }
+
+    // TODO
+    pub fn _disconnect(self: *MutationObserver) !void {
+        self.connected = false;
+    }
+
+    // TODO
+    pub fn _takeRecords(_: *const MutationObserver) ?[]const u8 {
+        return &[_]u8{};
+    }
+};
+
+pub const MutationRecord = struct {
+    type: []const u8,
+    target: *parser.Node,
+    added_nodes: NodeList = .{},
+    removed_nodes: NodeList = .{},
+    previous_sibling: ?*parser.Node = null,
+    next_sibling: ?*parser.Node = null,
+    attribute_name: ?[]const u8 = null,
+    attribute_namespace: ?[]const u8 = null,
+    old_value: ?[]const u8 = null,
+
+    pub fn get_type(self: *const MutationRecord) []const u8 {
+        return self.type;
+    }
+
+    pub fn get_addedNodes(self: *MutationRecord) *NodeList {
+        return &self.added_nodes;
+    }
+
+    pub fn get_removedNodes(self: *MutationRecord) *NodeList {
+        return &self.removed_nodes;
+    }
+
+    pub fn get_target(self: *const MutationRecord) *parser.Node {
+        return self.target;
+    }
+
+    pub fn get_attributeName(self: *const MutationRecord) ?[]const u8 {
+        return self.attribute_name;
+    }
+
+    pub fn get_attributeNamespace(self: *const MutationRecord) ?[]const u8 {
+        return self.attribute_namespace;
+    }
+
+    pub fn get_previousSibling(self: *const MutationRecord) ?*parser.Node {
+        return self.previous_sibling;
+    }
+
+    pub fn get_nextSibling(self: *const MutationRecord) ?*parser.Node {
+        return self.next_sibling;
+    }
+
+    pub fn get_oldValue(self: *const MutationRecord) ?[]const u8 {
+        return self.old_value;
+    }
+};
+
+const Options = struct {
+    childList: bool = false,
+    attributes: bool = false,
+    characterData: bool = false,
+    subtree: bool = false,
+    attributeOldValue: bool = false,
+    characterDataOldValue: bool = false,
+    attributeFilter: [][]const u8 = &.{},
+
+    fn attr(self: Options) bool {
+        return self.attributes or self.attributeOldValue or self.attributeFilter.len > 0;
+    }
+
+    fn cdata(self: Options) bool {
+        return self.characterData or self.characterDataOldValue;
+    }
+};
+
+const Observer = struct {
+    node: *parser.Node,
+    options: Options,
+
+    // reference back to the MutationObserver so that we can access the arena
+    // and batch the mutation records.
+    mutation_observer: *MutationObserver,
+
+    event_node: parser.EventNode,
+
+    fn appliesTo(
+        self: *const Observer,
+        target: *parser.Node,
+        event_type: MutationEventType,
+        event: *parser.MutationEvent,
+    ) !bool {
+        if (event_type == .DOMAttrModified and self.options.attributeFilter.len > 0) {
+            const attribute_name = try parser.mutationEventAttributeName(event);
+            for (self.options.attributeFilter) |needle| blk: {
+                if (std.mem.eql(u8, attribute_name, needle)) {
+                    break :blk;
+                }
+            }
+            return false;
+        }
+
+        // mutation on any target is always ok.
+        if (self.options.subtree) {
+            return true;
+        }
+
+        // if target equals node, alway ok.
+        if (target == self.node) {
+            return true;
+        }
+
+        // no subtree, no same target and no childlist, always noky.
+        if (!self.options.childList) {
+            return false;
+        }
+
+        // target must be a child of o.node
+        const walker = Walker{};
+        var next: ?*parser.Node = null;
+        while (true) {
+            next = walker.get_next(self.node, next) catch break orelse break;
+            if (next.? == target) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    fn handle(en: *parser.EventNode, event: *parser.Event) void {
+        const self: *Observer = @fieldParentPtr("event_node", en);
+        self._handle(event) catch |err| {
+            log.err(.web_api, "handle error", .{ .err = err, .source = "mutation observer" });
+        };
+    }
+
+    fn _handle(self: *Observer, event: *parser.Event) !void {
+        var mutation_observer = self.mutation_observer;
+
+        const node = blk: {
+            const event_target = try parser.eventTarget(event) orelse return;
+            break :blk parser.eventTargetToNode(event_target);
+        };
+
+        const mutation_event = parser.eventToMutationEvent(event);
+        const event_type = blk: {
+            const t = try parser.eventType(event);
+            break :blk std.meta.stringToEnum(MutationEventType, t) orelse return;
+        };
+
+        if (try self.appliesTo(node, event_type, mutation_event) == false) {
+            return;
+        }
+
+        var record = MutationRecord{
+            .target = self.node,
+            .type = event_type.recordType(),
+        };
+
+        const arena = mutation_observer.arena;
+        switch (event_type) {
+            .DOMAttrModified => {
+                record.attribute_name = parser.mutationEventAttributeName(mutation_event) catch null;
+                if (self.options.attributeOldValue) {
+                    record.old_value = parser.mutationEventPrevValue(mutation_event) catch null;
+                }
+            },
+            .DOMCharacterDataModified => {
+                if (self.options.characterDataOldValue) {
+                    record.old_value = parser.mutationEventPrevValue(mutation_event) catch null;
+                }
+            },
+            .DOMNodeInserted => {
+                if (parser.mutationEventRelatedNode(mutation_event) catch null) |related_node| {
+                    try record.added_nodes.append(arena, related_node);
+                }
+            },
+            .DOMNodeRemoved => {
+                if (parser.mutationEventRelatedNode(mutation_event) catch null) |related_node| {
+                    try record.removed_nodes.append(arena, related_node);
+                }
+            },
+        }
+
+        try mutation_observer.observed.append(arena, record);
+
+        if (mutation_observer.scheduled == false) {
+            mutation_observer.scheduled = true;
+            _ = try mutation_observer.loop.timeout(0, &mutation_observer.loop_node);
+        }
+    }
+};
+
+const MutationEventType = enum {
+    DOMAttrModified,
+    DOMCharacterDataModified,
+    DOMNodeInserted,
+    DOMNodeRemoved,
+
+    fn recordType(self: MutationEventType) []const u8 {
+        return switch (self) {
+            .DOMAttrModified => "attributes",
+            .DOMCharacterDataModified => "characterData",
+            .DOMNodeInserted => "childList",
+            .DOMNodeRemoved => "childList",
+        };
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.MutationObserver" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "new MutationObserver(() => {}).observe(document, { childList: true });", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ var nb = 0;
+            \\ var mrs;
+            \\ new MutationObserver((mu) => {
+            \\    mrs = mu;
+            \\    nb++;
+            \\ }).observe(document.firstElementChild, { attributes: true, attributeOldValue: true });
+            \\ document.firstElementChild.setAttribute("foo", "bar");
+            \\ // ignored b/c it's about another target.
+            \\ document.firstElementChild.firstChild.setAttribute("foo", "bar");
+            ,
+            null,
+        },
+        .{ "nb", "1" },
+        .{ "mrs[0].type", "attributes" },
+        .{ "mrs[0].target == document.firstElementChild", "true" },
+        .{ "mrs[0].target.getAttribute('foo')", "bar" },
+        .{ "mrs[0].attributeName", "foo" },
+        .{ "mrs[0].oldValue", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ var node = document.getElementById("para").firstChild;
+            \\ var nb2 = 0;
+            \\ var mrs2;
+            \\ new MutationObserver((mu) => {
+            \\     mrs2 = mu;
+            \\     nb2++;
+            \\ }).observe(node, { characterData: true, characterDataOldValue: true });
+            \\ node.data = "foo";
+            ,
+            null,
+        },
+        .{ "nb2", "1" },
+        .{ "mrs2[0].type", "characterData" },
+        .{ "mrs2[0].target == node", "true" },
+        .{ "mrs2[0].target.data", "foo" },
+        .{ "mrs2[0].oldValue", " And" },
+    }, .{});
+
+    // tests that mutation observers that have a callback which trigger the
+    // mutation observer don't crash.
+    // https://github.com/lightpanda-io/browser/issues/550
+    try runner.testCases(&.{
+        .{
+            \\ var node = document.getElementById("para");
+            \\ new MutationObserver(() => {
+            \\     node.innerText = 'a';
+            \\ }).observe(document, { subtree:true,childList:true });
+            \\ node.innerText = "2";
+            ,
+            null,
+        },
+        .{ "node.innerText", "a" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ var node = document.getElementById("para");
+            \\ var attrWatch = 0;
+            \\ new MutationObserver(() => {
+            \\     attrWatch++;
+            \\ }).observe(document, { attributeFilter: ["name"], subtree: true });
+            \\ node.setAttribute("id", "1");
+            ,
+            null,
+        },
+        .{ "attrWatch", "0" },
+        .{ "node.setAttribute('name', 'other');", null },
+        .{ "attrWatch", "1" },
+    }, .{});
+}
--- a/src/browser/dom/namednodemap.zig
+++ b/src/browser/dom/namednodemap.zig
@@ -0,0 +1,140 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+
+const DOMException = @import("exceptions.zig").DOMException;
+
+// WEB IDL https://dom.spec.whatwg.org/#namednodemap
+pub const NamedNodeMap = struct {
+    pub const Self = parser.NamedNodeMap;
+
+    pub const Exception = DOMException;
+    pub const Iterator = NamedNodeMapIterator;
+
+    // TODO implement LegacyUnenumerableNamedProperties.
+    // https://webidl.spec.whatwg.org/#LegacyUnenumerableNamedProperties
+
+    pub fn get_length(self: *parser.NamedNodeMap) !u32 {
+        return try parser.namedNodeMapGetLength(self);
+    }
+
+    pub fn _item(self: *parser.NamedNodeMap, index: u32) !?*parser.Attribute {
+        return try parser.namedNodeMapItem(self, index);
+    }
+
+    pub fn _getNamedItem(self: *parser.NamedNodeMap, qname: []const u8) !?*parser.Attribute {
+        return try parser.namedNodeMapGetNamedItem(self, qname);
+    }
+
+    pub fn _getNamedItemNS(
+        self: *parser.NamedNodeMap,
+        namespace: []const u8,
+        localname: []const u8,
+    ) !?*parser.Attribute {
+        return try parser.namedNodeMapGetNamedItemNS(self, namespace, localname);
+    }
+
+    pub fn _setNamedItem(self: *parser.NamedNodeMap, attr: *parser.Attribute) !?*parser.Attribute {
+        return try parser.namedNodeMapSetNamedItem(self, attr);
+    }
+
+    pub fn _setNamedItemNS(self: *parser.NamedNodeMap, attr: *parser.Attribute) !?*parser.Attribute {
+        return try parser.namedNodeMapSetNamedItemNS(self, attr);
+    }
+
+    pub fn _removeNamedItem(self: *parser.NamedNodeMap, qname: []const u8) !*parser.Attribute {
+        return try parser.namedNodeMapRemoveNamedItem(self, qname);
+    }
+
+    pub fn _removeNamedItemNS(
+        self: *parser.NamedNodeMap,
+        namespace: []const u8,
+        localname: []const u8,
+    ) !*parser.Attribute {
+        return try parser.namedNodeMapRemoveNamedItemNS(self, namespace, localname);
+    }
+
+    pub fn indexed_get(self: *parser.NamedNodeMap, index: u32, has_value: *bool) !*parser.Attribute {
+        return (try _item(self, index)) orelse {
+            has_value.* = false;
+            return undefined;
+        };
+    }
+
+    pub fn named_get(self: *parser.NamedNodeMap, name: []const u8, has_value: *bool) !*parser.Attribute {
+        return (try _getNamedItem(self, name)) orelse {
+            has_value.* = false;
+            return undefined;
+        };
+    }
+
+    pub fn _symbol_iterator(self: *parser.NamedNodeMap) NamedNodeMapIterator {
+        return .{ .map = self };
+    }
+};
+
+pub const NamedNodeMapIterator = struct {
+    index: u32 = 0,
+    map: *parser.NamedNodeMap,
+
+    pub const Return = struct {
+        done: bool,
+        value: ?*parser.Attribute,
+    };
+
+    pub fn _next(self: *NamedNodeMapIterator) !Return {
+        const e = try NamedNodeMap._item(self.map, self.index);
+        if (e == null) {
+            return .{
+                .value = null,
+                .done = true,
+            };
+        }
+
+        self.index += 1;
+        return .{
+            .value = e,
+            .done = false,
+        };
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.NamedNodeMap" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let a = document.getElementById('content').attributes", "undefined" },
+        .{ "a.length", "1" },
+        .{ "a.item(0)", "[object Attr]" },
+        .{ "a.item(1)", "null" },
+        .{ "a.getNamedItem('id')", "[object Attr]" },
+        .{ "a.getNamedItem('foo')", "null" },
+        .{ "a.setNamedItem(a.getNamedItem('id'))", "[object Attr]" },
+        .{ "a['id'].name", "id" },
+        .{ "a['id'].value", "content" },
+        .{ "a['other']", "undefined" },
+        .{ "a[0].value = 'abc123'", null },
+        .{ "a[0].value", "abc123" },
+    }, .{});
+}
--- a/src/browser/dom/node.zig
+++ b/src/browser/dom/node.zig
@@ -0,0 +1,722 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const generate = @import("../../runtime/generate.zig");
+
+const Page = @import("../page.zig").Page;
+const EventTarget = @import("event_target.zig").EventTarget;
+
+// DOM
+const Attr = @import("attribute.zig").Attr;
+const CData = @import("character_data.zig");
+const Element = @import("element.zig").Element;
+const NodeList = @import("nodelist.zig").NodeList;
+const Document = @import("document.zig").Document;
+const DocumentType = @import("document_type.zig").DocumentType;
+const DocumentFragment = @import("document_fragment.zig").DocumentFragment;
+const HTMLCollection = @import("html_collection.zig").HTMLCollection;
+const HTMLAllCollection = @import("html_collection.zig").HTMLAllCollection;
+const HTMLCollectionIterator = @import("html_collection.zig").HTMLCollectionIterator;
+const Walker = @import("walker.zig").WalkerDepthFirst;
+
+// HTML
+const HTML = @import("../html/html.zig");
+const HTMLElem = @import("../html/elements.zig");
+
+// Node interfaces
+pub const Interfaces = .{
+    Attr,
+    CData.CharacterData,
+    CData.Interfaces,
+    Element,
+    Document,
+    DocumentType,
+    DocumentFragment,
+    HTMLCollection,
+    HTMLAllCollection,
+    HTMLCollectionIterator,
+    HTML.Interfaces,
+};
+
+pub const Union = generate.Union(Interfaces);
+
+// Node implementation
+pub const Node = struct {
+    pub const Self = parser.Node;
+    pub const prototype = *EventTarget;
+    pub const subtype = .node;
+
+    pub fn toInterface(node: *parser.Node) !Union {
+        return switch (try parser.nodeType(node)) {
+            .element => try HTMLElem.toInterface(
+                Union,
+                @as(*parser.Element, @ptrCast(node)),
+            ),
+            .comment => .{ .Comment = @as(*parser.Comment, @ptrCast(node)) },
+            .text => .{ .Text = @as(*parser.Text, @ptrCast(node)) },
+            .cdata_section => .{ .CDATASection = @as(*parser.CDATASection, @ptrCast(node)) },
+            .processing_instruction => .{ .ProcessingInstruction = @as(*parser.ProcessingInstruction, @ptrCast(node)) },
+            .document => .{ .HTMLDocument = @as(*parser.DocumentHTML, @ptrCast(node)) },
+            .document_type => .{ .DocumentType = @as(*parser.DocumentType, @ptrCast(node)) },
+            .attribute => .{ .Attr = @as(*parser.Attribute, @ptrCast(node)) },
+            .document_fragment => .{ .DocumentFragment = @as(*parser.DocumentFragment, @ptrCast(node)) },
+            else => @panic("node type not handled"), // TODO
+        };
+    }
+
+    // class attributes
+
+    pub const _ELEMENT_NODE = @intFromEnum(parser.NodeType.element);
+    pub const _ATTRIBUTE_NODE = @intFromEnum(parser.NodeType.attribute);
+    pub const _TEXT_NODE = @intFromEnum(parser.NodeType.text);
+    pub const _CDATA_SECTION_NODE = @intFromEnum(parser.NodeType.cdata_section);
+    pub const _PROCESSING_INSTRUCTION_NODE = @intFromEnum(parser.NodeType.processing_instruction);
+    pub const _COMMENT_NODE = @intFromEnum(parser.NodeType.comment);
+    pub const _DOCUMENT_NODE = @intFromEnum(parser.NodeType.document);
+    pub const _DOCUMENT_TYPE_NODE = @intFromEnum(parser.NodeType.document_type);
+    pub const _DOCUMENT_FRAGMENT_NODE = @intFromEnum(parser.NodeType.document_fragment);
+
+    // These 3 are deprecated, but both Chrome and Firefox still expose them
+    pub const _ENTITY_REFERENCE_NODE = @intFromEnum(parser.NodeType.entity_reference);
+    pub const _ENTITY_NODE = @intFromEnum(parser.NodeType.entity);
+    pub const _NOTATION_NODE = @intFromEnum(parser.NodeType.notation);
+
+    // JS funcs
+    // --------
+
+    // Read-only attributes
+
+    pub fn get_firstChild(self: *parser.Node) !?Union {
+        const res = try parser.nodeFirstChild(self);
+        if (res == null) {
+            return null;
+        }
+        return try Node.toInterface(res.?);
+    }
+
+    pub fn get_lastChild(self: *parser.Node) !?Union {
+        const res = try parser.nodeLastChild(self);
+        if (res == null) {
+            return null;
+        }
+        return try Node.toInterface(res.?);
+    }
+
+    pub fn get_nextSibling(self: *parser.Node) !?Union {
+        const res = try parser.nodeNextSibling(self);
+        if (res == null) {
+            return null;
+        }
+        return try Node.toInterface(res.?);
+    }
+
+    pub fn get_previousSibling(self: *parser.Node) !?Union {
+        const res = try parser.nodePreviousSibling(self);
+        if (res == null) {
+            return null;
+        }
+        return try Node.toInterface(res.?);
+    }
+
+    pub fn get_parentNode(self: *parser.Node) !?Union {
+        const res = try parser.nodeParentNode(self);
+        if (res == null) {
+            return null;
+        }
+        return try Node.toInterface(res.?);
+    }
+
+    pub fn get_parentElement(self: *parser.Node) !?HTMLElem.Union {
+        const res = try parser.nodeParentElement(self);
+        if (res == null) {
+            return null;
+        }
+        return try HTMLElem.toInterface(HTMLElem.Union, @as(*parser.Element, @ptrCast(res.?)));
+    }
+
+    pub fn get_nodeName(self: *parser.Node) ![]const u8 {
+        return try parser.nodeName(self);
+    }
+
+    pub fn get_nodeType(self: *parser.Node) !u8 {
+        return @intFromEnum(try parser.nodeType(self));
+    }
+
+    pub fn get_ownerDocument(self: *parser.Node) !?*parser.DocumentHTML {
+        const res = try parser.nodeOwnerDocument(self);
+        if (res == null) {
+            return null;
+        }
+        return @as(*parser.DocumentHTML, @ptrCast(res.?));
+    }
+
+    pub fn get_isConnected(self: *parser.Node) !bool {
+        // TODO: handle Shadow DOM
+        if (try parser.nodeType(self) == .document) {
+            return true;
+        }
+        return try Node.get_parentNode(self) != null;
+    }
+
+    // Read/Write attributes
+
+    pub fn get_nodeValue(self: *parser.Node) !?[]const u8 {
+        return try parser.nodeValue(self);
+    }
+
+    pub fn set_nodeValue(self: *parser.Node, data: []u8) !void {
+        try parser.nodeSetValue(self, data);
+    }
+
+    pub fn get_textContent(self: *parser.Node) !?[]const u8 {
+        return try parser.nodeTextContent(self);
+    }
+
+    pub fn set_textContent(self: *parser.Node, data: []u8) !void {
+        return try parser.nodeSetTextContent(self, data);
+    }
+
+    // Methods
+
+    pub fn _appendChild(self: *parser.Node, child: *parser.Node) !Union {
+        // TODO: DocumentFragment special case
+        const res = try parser.nodeAppendChild(self, child);
+        return try Node.toInterface(res);
+    }
+
+    pub fn _cloneNode(self: *parser.Node, deep: ?bool) !Union {
+        const clone = try parser.nodeCloneNode(self, deep orelse false);
+        return try Node.toInterface(clone);
+    }
+
+    pub fn _compareDocumentPosition(self: *parser.Node, other: *parser.Node) !u32 {
+        if (self == other) return 0;
+
+        const docself = try parser.nodeOwnerDocument(self);
+        const docother = try parser.nodeOwnerDocument(other);
+
+        // Both are in different document.
+        if (docself == null or docother == null or docother.? != docself.?) {
+            return @intFromEnum(parser.DocumentPosition.disconnected);
+        }
+
+        // TODO Both are in a different trees in the same document.
+
+        const w = Walker{};
+        var next: ?*parser.Node = null;
+
+        // Is other a descendant of self?
+        while (true) {
+            next = try w.get_next(self, next) orelse break;
+            if (other == next) {
+                return @intFromEnum(parser.DocumentPosition.following) +
+                    @intFromEnum(parser.DocumentPosition.contained_by);
+            }
+        }
+
+        // Is self a descendant of other?
+        next = null;
+        while (true) {
+            next = try w.get_next(other, next) orelse break;
+            if (self == next) {
+                return @intFromEnum(parser.DocumentPosition.contains) +
+                    @intFromEnum(parser.DocumentPosition.preceding);
+            }
+        }
+
+        next = null;
+        while (true) {
+            next = try w.get_next(parser.documentToNode(docself.?), next) orelse break;
+            if (other == next) {
+                // other precedes self.
+                return @intFromEnum(parser.DocumentPosition.preceding);
+            }
+            if (self == next) {
+                // other follows self.
+                return @intFromEnum(parser.DocumentPosition.following);
+            }
+        }
+
+        return 0;
+    }
+
+    pub fn _contains(self: *parser.Node, other: *parser.Node) !bool {
+        return try parser.nodeContains(self, other);
+    }
+
+    // Returns itself or ancestor object inheriting from Node.
+    // - An Element inside a standard web page will return an HTMLDocument object representing the entire page (or <iframe>).
+    // - An Element inside a shadow DOM will return the associated ShadowRoot.
+    // - An Element that is not attached to a document or a shadow tree will return the root of the DOM tree it belongs to
+    pub fn _getRootNode(self: *parser.Node, options: ?struct { composed: bool = false }) !Union {
+        if (options) |options_| if (options_.composed) {
+            log.warn(.web_api, "not implemented", .{ .feature = "getRootNode composed" });
+        };
+        return try Node.toInterface(try parser.nodeGetRootNode(self));
+    }
+
+    pub fn _hasChildNodes(self: *parser.Node) !bool {
+        return try parser.nodeHasChildNodes(self);
+    }
+
+    pub fn get_childNodes(self: *parser.Node, page: *Page) !NodeList {
+        const allocator = page.arena;
+        var list: NodeList = .{};
+
+        var n = try parser.nodeFirstChild(self) orelse return list;
+        while (true) {
+            try list.append(allocator, n);
+            n = try parser.nodeNextSibling(n) orelse return list;
+        }
+    }
+
+    pub fn _insertBefore(self: *parser.Node, new_node: *parser.Node, ref_node_: ?*parser.Node) !Union {
+        if (ref_node_) |ref_node| {
+            return Node.toInterface(try parser.nodeInsertBefore(self, new_node, ref_node));
+        }
+        return _appendChild(self, new_node);
+    }
+
+    pub fn _isDefaultNamespace(self: *parser.Node, namespace: ?[]const u8) !bool {
+        return try parser.nodeIsDefaultNamespace(self, namespace);
+    }
+
+    pub fn _isEqualNode(self: *parser.Node, other: *parser.Node) !bool {
+        // TODO: other is not an optional parameter, but can be null.
+        return try parser.nodeIsEqualNode(self, other);
+    }
+
+    pub fn _isSameNode(self: *parser.Node, other: *parser.Node) !bool {
+        // TODO: other is not an optional parameter, but can be null.
+        // NOTE: there is no need to use isSameNode(); instead use the === strict equality operator
+        return try parser.nodeIsSameNode(self, other);
+    }
+
+    pub fn _lookupPrefix(self: *parser.Node, namespace: ?[]const u8) !?[]const u8 {
+        // TODO: other is not an optional parameter, but can be null.
+        if (namespace == null) {
+            return null;
+        }
+        if (std.mem.eql(u8, namespace.?, "")) {
+            return null;
+        }
+        return try parser.nodeLookupPrefix(self, namespace.?);
+    }
+
+    pub fn _lookupNamespaceURI(self: *parser.Node, prefix: ?[]const u8) !?[]const u8 {
+        // TODO: other is not an optional parameter, but can be null.
+        return try parser.nodeLookupNamespaceURI(self, prefix);
+    }
+
+    pub fn _normalize(self: *parser.Node) !void {
+        return try parser.nodeNormalize(self);
+    }
+
+    pub fn _removeChild(self: *parser.Node, child: *parser.Node) !Union {
+        const res = try parser.nodeRemoveChild(self, child);
+        return try Node.toInterface(res);
+    }
+
+    pub fn _replaceChild(self: *parser.Node, new_child: *parser.Node, old_child: *parser.Node) !Union {
+        const res = try parser.nodeReplaceChild(self, new_child, old_child);
+        return try Node.toInterface(res);
+    }
+
+    // Check if the hierarchy node tree constraints are respected.
+    // For now, it checks only if new nodes are not self.
+    // TODO implements the others contraints.
+    // see https://dom.spec.whatwg.org/#concept-node-tree
+    pub fn hierarchy(self: *parser.Node, nodes: []const NodeOrText) bool {
+        for (nodes) |n| {
+            if (n.is(self)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    pub fn prepend(self: *parser.Node, nodes: []const NodeOrText) !void {
+        if (nodes.len == 0) {
+            return;
+        }
+
+        // check hierarchy
+        if (!hierarchy(self, nodes)) {
+            return parser.DOMError.HierarchyRequest;
+        }
+
+        const doc = (try parser.nodeOwnerDocument(self)) orelse return;
+
+        if (try parser.nodeFirstChild(self)) |first| {
+            for (nodes) |node| {
+                _ = try parser.nodeInsertBefore(self, try node.toNode(doc), first);
+            }
+            return;
+        }
+
+        for (nodes) |node| {
+            _ = try parser.nodeAppendChild(self, try node.toNode(doc));
+        }
+    }
+
+    pub fn append(self: *parser.Node, nodes: []const NodeOrText) !void {
+        if (nodes.len == 0) {
+            return;
+        }
+
+        // check hierarchy
+        if (!hierarchy(self, nodes)) {
+            return parser.DOMError.HierarchyRequest;
+        }
+
+        const doc = (try parser.nodeOwnerDocument(self)) orelse return;
+        for (nodes) |node| {
+            _ = try parser.nodeAppendChild(self, try node.toNode(doc));
+        }
+    }
+
+    pub fn replaceChildren(self: *parser.Node, nodes: []const NodeOrText) !void {
+        if (nodes.len == 0) {
+            return;
+        }
+
+        // check hierarchy
+        if (!hierarchy(self, nodes)) {
+            return parser.DOMError.HierarchyRequest;
+        }
+
+        // remove existing children
+        try removeChildren(self);
+
+        const doc = (try parser.nodeOwnerDocument(self)) orelse return;
+        // add new children
+        for (nodes) |node| {
+            _ = try parser.nodeAppendChild(self, try node.toNode(doc));
+        }
+    }
+
+    pub fn removeChildren(self: *parser.Node) !void {
+        if (!try parser.nodeHasChildNodes(self)) return;
+
+        const children = try parser.nodeGetChildNodes(self);
+        const ln = try parser.nodeListLength(children);
+        var i: u32 = 0;
+        while (i < ln) {
+            defer i += 1;
+            // we always retrieve the 0 index child on purpose: libdom nodelist
+            // are dynamic. So the next child to remove is always as pos 0.
+            const child = try parser.nodeListItem(children, 0) orelse continue;
+            _ = try parser.nodeRemoveChild(self, child);
+        }
+    }
+
+    pub fn before(self: *parser.Node, nodes: []const NodeOrText) !void {
+        const parent = try parser.nodeParentNode(self) orelse return;
+        const doc = (try parser.nodeOwnerDocument(parent)) orelse return;
+
+        var sibling: ?*parser.Node = self;
+        // have to find the first sibling that isn't in nodes
+        CHECK: while (sibling) |s| {
+            for (nodes) |n| {
+                if (n.is(s)) {
+                    sibling = try parser.nodePreviousSibling(s);
+                    continue :CHECK;
+                }
+            }
+            break;
+        }
+
+        if (sibling == null) {
+            sibling = try parser.nodeFirstChild(parent);
+        }
+
+        if (sibling) |ref_node| {
+            for (nodes) |node| {
+                _ = try parser.nodeInsertBefore(parent, try node.toNode(doc), ref_node);
+            }
+            return;
+        }
+
+        return Node.prepend(self, nodes);
+    }
+
+    pub fn after(self: *parser.Node, nodes: []const NodeOrText) !void {
+        const parent = try parser.nodeParentNode(self) orelse return;
+        const doc = (try parser.nodeOwnerDocument(parent)) orelse return;
+
+        // have to find the first sibling that isn't in nodes
+        var sibling = try parser.nodeNextSibling(self);
+        CHECK: while (sibling) |s| {
+            for (nodes) |n| {
+                if (n.is(s)) {
+                    sibling = try parser.nodeNextSibling(s);
+                    continue :CHECK;
+                }
+            }
+            break;
+        }
+
+        if (sibling) |ref_node| {
+            for (nodes) |node| {
+                _ = try parser.nodeInsertBefore(parent, try node.toNode(doc), ref_node);
+            }
+            return;
+        }
+
+        for (nodes) |node| {
+            _ = try parser.nodeAppendChild(parent, try node.toNode(doc));
+        }
+    }
+
+    // A lot of functions take either a node or text input.
+    // The text input is to be converted into a Text node.
+    pub const NodeOrText = union(enum) {
+        text: []const u8,
+        node: *parser.Node,
+
+        fn toNode(self: NodeOrText, doc: *parser.Document) !*parser.Node {
+            return switch (self) {
+                .node => |n| n,
+                .text => |txt| @alignCast(@ptrCast(try parser.documentCreateTextNode(doc, txt))),
+            };
+        }
+
+        // Whether the node represented by the NodeOrText is the same as the
+        // given Node. Always false for text values as these represent as-of-yet
+        // created Text nodes.
+        fn is(self: NodeOrText, other: *parser.Node) bool {
+            return switch (self) {
+                .text => false,
+                .node => |n| n == other,
+            };
+        }
+    };
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.node" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    {
+        var err_out: ?[]const u8 = null;
+        try runner.exec(
+            \\ function trimAndReplace(str) {
+            \\   str = str.replace(/(\r\n|\n|\r)/gm,'');
+            \\   str = str.replace(/\s+/g, ' ');
+            \\   str = str.trim();
+            \\   return str;
+            \\ }
+        , "trimAndReplace", &err_out);
+    }
+
+    try runner.testCases(&.{
+        .{ "document.body.compareDocumentPosition(document.firstChild); ", "10" },
+        .{ "document.getElementById(\"para-empty\").compareDocumentPosition(document.getElementById(\"content\"));", "10" },
+        .{ "document.getElementById(\"content\").compareDocumentPosition(document.getElementById(\"para-empty\"));", "20" },
+        .{ "document.getElementById(\"link\").compareDocumentPosition(document.getElementById(\"link\"));", "0" },
+        .{ "document.getElementById(\"para-empty\").compareDocumentPosition(document.getElementById(\"link\"));", "2" },
+        .{ "document.getElementById(\"link\").compareDocumentPosition(document.getElementById(\"para-empty\"));", "4" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.getElementById('content').getRootNode().__proto__.constructor.name", "HTMLDocument" },
+    }, .{});
+
+    try runner.testCases(&.{
+        // for next test cases
+        .{ "let content = document.getElementById('content')", "undefined" },
+        .{ "let link = document.getElementById('link')", "undefined" },
+        .{ "let first_child = content.firstChild.nextSibling", "undefined" }, // nextSibling because of line return \n
+
+        .{ "let body_first_child = document.body.firstChild", "undefined" },
+        .{ "body_first_child.localName", "div" },
+        .{ "body_first_child.__proto__.constructor.name", "HTMLDivElement" },
+        .{ "document.getElementById('para-empty').firstChild.firstChild", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let last_child = content.lastChild.previousSibling", "undefined" }, // previousSibling because of line return \n
+        .{ "last_child.__proto__.constructor.name", "Comment" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let next_sibling = link.nextSibling.nextSibling", "undefined" },
+        .{ "next_sibling.localName", "p" },
+        .{ "next_sibling.__proto__.constructor.name", "HTMLParagraphElement" },
+        .{ "content.nextSibling.nextSibling", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let prev_sibling = document.getElementById('para-empty').previousSibling.previousSibling", "undefined" },
+        .{ "prev_sibling.localName", "a" },
+        .{ "prev_sibling.__proto__.constructor.name", "HTMLAnchorElement" },
+        .{ "content.previousSibling", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let parent = document.getElementById('para').parentElement", "undefined" },
+        .{ "parent.localName", "div" },
+        .{ "parent.__proto__.constructor.name", "HTMLDivElement" },
+        .{ "let h = content.parentElement.parentElement", "undefined" },
+        .{ "h.parentElement", "null" },
+        .{ "h.parentNode.__proto__.constructor.name", "HTMLDocument" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "first_child.nodeName === 'A'", "true" },
+        .{ "link.firstChild.nodeName === '#text'", "true" },
+        .{ "last_child.nodeName === '#comment'", "true" },
+        .{ "document.nodeName === '#document'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "first_child.nodeType === 1", "true" },
+        .{ "link.firstChild.nodeType === 3", "true" },
+        .{ "last_child.nodeType === 8", "true" },
+        .{ "document.nodeType === 9", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let owner = content.ownerDocument", "undefined" },
+        .{ "owner.__proto__.constructor.name", "HTMLDocument" },
+        .{ "document.ownerDocument", "null" },
+        .{ "let owner2 = document.createElement('div').ownerDocument", "undefined" },
+        .{ "owner2.__proto__.constructor.name", "HTMLDocument" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "content.isConnected", "true" },
+        .{ "document.isConnected", "true" },
+        .{ "document.createElement('div').isConnected", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "last_child.nodeValue === 'comment'", "true" },
+        .{ "link.nodeValue === null", "true" },
+        .{ "let text = link.firstChild", "undefined" },
+        .{ "text.nodeValue === 'OK'", "true" },
+        .{ "text.nodeValue = 'OK modified'", "OK modified" },
+        .{ "text.nodeValue === 'OK modified'", "true" },
+        .{ "link.nodeValue = 'nothing'", "nothing" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "text.textContent === 'OK modified'", "true" },
+        .{ "trimAndReplace(content.textContent) === 'OK modified And'", "true" },
+        .{ "text.textContent = 'OK'", "OK" },
+        .{ "text.textContent", "OK" },
+        .{ "trimAndReplace(document.getElementById('para-empty').textContent)", "" },
+        .{ "document.getElementById('para-empty').textContent = 'OK'", "OK" },
+        .{ "document.getElementById('para-empty').firstChild.nodeName === '#text'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let append = document.createElement('h1')", "undefined" },
+        .{ "content.appendChild(append).toString()", "[object HTMLHeadingElement]" },
+        .{ "content.lastChild.__proto__.constructor.name", "HTMLHeadingElement" },
+        .{ "content.appendChild(link).toString()", "[object HTMLAnchorElement]" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let clone = link.cloneNode()", "undefined" },
+        .{ "clone.toString()", "[object HTMLAnchorElement]" },
+        .{ "clone.parentNode === null", "true" },
+        .{ "clone.firstChild === null", "true" },
+        .{ "let clone_deep = link.cloneNode(true)", "undefined" },
+        .{ "clone_deep.firstChild.nodeName === '#text'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "link.contains(text)", "true" },
+        .{ "text.contains(link)", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "link.hasChildNodes()", "true" },
+        .{ "text.hasChildNodes()", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "link.childNodes.length", "1" },
+        .{ "text.childNodes.length", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let insertBefore = document.createElement('a')", "undefined" },
+        .{ "link.insertBefore(insertBefore, text) !== undefined", "true" },
+        .{ "link.firstChild.localName === 'a'", "true" },
+
+        .{ "let insertBefore2 = document.createElement('b')", null },
+        .{ "link.insertBefore(insertBefore2, null).localName", "b" },
+        .{ "link.childNodes[link.childNodes.length - 1].localName", "b" },
+    }, .{});
+
+    try runner.testCases(&.{
+        // TODO: does not seems to work
+        // .{ "link.isDefaultNamespace('')", "true" },
+        .{ "link.isDefaultNamespace('false')", "false" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let equal1 = document.createElement('a')", "undefined" },
+        .{ "let equal2 = document.createElement('a')", "undefined" },
+        .{ "equal1.textContent = 'is equal'", "is equal" },
+        .{ "equal2.textContent = 'is equal'", "is equal" },
+        // TODO: does not seems to work
+        // .{ "equal1.isEqualNode(equal2)", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.body.isSameNode(document.body)", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        // TODO: no test
+        .{ "link.normalize()", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "content.removeChild(append) !== undefined", "true" },
+        .{ "last_child.__proto__.constructor.name !== 'HTMLHeadingElement'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let replace = document.createElement('div')", "undefined" },
+        .{ "link.replaceChild(replace, insertBefore) !== undefined", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "Node.ELEMENT_NODE", "1" },
+        .{ "Node.ATTRIBUTE_NODE", "2" },
+        .{ "Node.TEXT_NODE", "3" },
+        .{ "Node.CDATA_SECTION_NODE", "4" },
+        .{ "Node.PROCESSING_INSTRUCTION_NODE", "7" },
+        .{ "Node.COMMENT_NODE", "8" },
+        .{ "Node.DOCUMENT_NODE", "9" },
+        .{ "Node.DOCUMENT_TYPE_NODE", "10" },
+        .{ "Node.DOCUMENT_FRAGMENT_NODE", "11" },
+        .{ "Node.ENTITY_REFERENCE_NODE", "5" },
+        .{ "Node.ENTITY_NODE", "6" },
+        .{ "Node.NOTATION_NODE", "12" },
+    }, .{});
+}
--- a/src/browser/dom/node_filter.zig
+++ b/src/browser/dom/node_filter.zig
@@ -0,0 +1,89 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+const Env = @import("../env.zig").Env;
+const Node = @import("node.zig").Node;
+
+pub const NodeFilter = struct {
+    pub const _FILTER_ACCEPT: u16 = 1;
+    pub const _FILTER_REJECT: u16 = 2;
+    pub const _FILTER_SKIP: u16 = 3;
+
+    pub const _SHOW_ALL: u32 = std.math.maxInt(u32);
+    pub const _SHOW_ELEMENT: u32 = 0b1;
+    pub const _SHOW_ATTRIBUTE: u32 = 0b10;
+    pub const _SHOW_TEXT: u32 = 0b100;
+    pub const _SHOW_CDATA_SECTION: u32 = 0b1000;
+    pub const _SHOW_ENTITY_REFERENCE: u32 = 0b10000;
+    pub const _SHOW_ENTITY: u32 = 0b100000;
+    pub const _SHOW_PROCESSING_INSTRUCTION: u32 = 0b1000000;
+    pub const _SHOW_COMMENT: u32 = 0b10000000;
+    pub const _SHOW_DOCUMENT: u32 = 0b100000000;
+    pub const _SHOW_DOCUMENT_TYPE: u32 = 0b1000000000;
+    pub const _SHOW_DOCUMENT_FRAGMENT: u32 = 0b10000000000;
+    pub const _SHOW_NOTATION: u32 = 0b100000000000;
+};
+
+const VerifyResult = enum { accept, skip, reject };
+
+pub fn verify(what_to_show: u32, filter: ?Env.Function, node: *parser.Node) !VerifyResult {
+    const node_type = try parser.nodeType(node);
+
+    // Verify that we can show this node type.
+    if (!switch (node_type) {
+        .attribute => what_to_show & NodeFilter._SHOW_ATTRIBUTE != 0,
+        .cdata_section => what_to_show & NodeFilter._SHOW_CDATA_SECTION != 0,
+        .comment => what_to_show & NodeFilter._SHOW_COMMENT != 0,
+        .document => what_to_show & NodeFilter._SHOW_DOCUMENT != 0,
+        .document_fragment => what_to_show & NodeFilter._SHOW_DOCUMENT_FRAGMENT != 0,
+        .document_type => what_to_show & NodeFilter._SHOW_DOCUMENT_TYPE != 0,
+        .element => what_to_show & NodeFilter._SHOW_ELEMENT != 0,
+        .entity => what_to_show & NodeFilter._SHOW_ENTITY != 0,
+        .entity_reference => what_to_show & NodeFilter._SHOW_ENTITY_REFERENCE != 0,
+        .notation => what_to_show & NodeFilter._SHOW_NOTATION != 0,
+        .processing_instruction => what_to_show & NodeFilter._SHOW_PROCESSING_INSTRUCTION != 0,
+        .text => what_to_show & NodeFilter._SHOW_TEXT != 0,
+    }) return .reject;
+
+    // Verify that we aren't filtering it out.
+    if (filter) |f| {
+        const acceptance = try f.call(u16, .{try Node.toInterface(node)});
+        return switch (acceptance) {
+            NodeFilter._FILTER_ACCEPT => .accept,
+            NodeFilter._FILTER_REJECT => .reject,
+            NodeFilter._FILTER_SKIP => .skip,
+            else => .reject,
+        };
+    } else return .accept;
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.NodeFilter" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "NodeFilter.FILTER_ACCEPT", "1" },
+        .{ "NodeFilter.FILTER_REJECT", "2" },
+        .{ "NodeFilter.FILTER_SKIP", "3" },
+        .{ "NodeFilter.SHOW_ALL", "4294967295" },
+        .{ "NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_COMMENT", "129" },
+    }, .{});
+}
--- a/src/browser/dom/node_iterator.zig
+++ b/src/browser/dom/node_iterator.zig
@@ -0,0 +1,290 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+const Env = @import("../env.zig").Env;
+const NodeFilter = @import("node_filter.zig");
+const Node = @import("node.zig").Node;
+const NodeUnion = @import("node.zig").Union;
+
+// https://developer.mozilla.org/en-US/docs/Web/API/NodeIterator
+// While this is similar to TreeWalker it has its own implementation as there are several subtle differences
+// For example:
+// - nextNode returns the reference node, whereas TreeWalker returns the next node
+// - Skip and reject are equivalent for NodeIterator, for TreeWalker they are different
+pub const NodeIterator = struct {
+    root: *parser.Node,
+    reference_node: *parser.Node,
+    what_to_show: u32,
+    filter: ?NodeIteratorOpts,
+    filter_func: ?Env.Function,
+
+    pointer_before_current: bool = true,
+
+    pub const NodeIteratorOpts = union(enum) {
+        function: Env.Function,
+        object: struct { acceptNode: Env.Function },
+    };
+
+    pub fn init(node: *parser.Node, what_to_show: ?u32, filter: ?NodeIteratorOpts) !NodeIterator {
+        var filter_func: ?Env.Function = null;
+        if (filter) |f| {
+            filter_func = switch (f) {
+                .function => |func| func,
+                .object => |o| o.acceptNode,
+            };
+        }
+
+        return .{
+            .root = node,
+            .reference_node = node,
+            .what_to_show = what_to_show orelse NodeFilter.NodeFilter._SHOW_ALL,
+            .filter = filter,
+            .filter_func = filter_func,
+        };
+    }
+
+    pub fn get_filter(self: *const NodeIterator) ?NodeIteratorOpts {
+        return self.filter;
+    }
+
+    pub fn get_pointerBeforeReferenceNode(self: *const NodeIterator) bool {
+        return self.pointer_before_current;
+    }
+
+    pub fn get_referenceNode(self: *const NodeIterator) !NodeUnion {
+        return try Node.toInterface(self.reference_node);
+    }
+
+    pub fn get_root(self: *const NodeIterator) !NodeUnion {
+        return try Node.toInterface(self.root);
+    }
+
+    pub fn get_whatToShow(self: *const NodeIterator) u32 {
+        return self.what_to_show;
+    }
+
+    pub fn _nextNode(self: *NodeIterator) !?NodeUnion {
+        if (self.pointer_before_current) { // Unlike TreeWalker, NodeIterator starts at the first node
+            self.pointer_before_current = false;
+            if (.accept == try NodeFilter.verify(self.what_to_show, self.filter_func, self.reference_node)) {
+                return try Node.toInterface(self.reference_node);
+            }
+        }
+
+        if (try self.firstChild(self.reference_node)) |child| {
+            self.reference_node = child;
+            return try Node.toInterface(child);
+        }
+
+        var current = self.reference_node;
+        while (current != self.root) {
+            if (try self.nextSibling(current)) |sibling| {
+                self.reference_node = sibling;
+                return try Node.toInterface(sibling);
+            }
+
+            current = (try parser.nodeParentNode(current)) orelse break;
+        }
+
+        return null;
+    }
+
+    pub fn _previousNode(self: *NodeIterator) !?NodeUnion {
+        if (!self.pointer_before_current) {
+            self.pointer_before_current = true;
+            if (.accept == try NodeFilter.verify(self.what_to_show, self.filter_func, self.reference_node)) {
+                return try Node.toInterface(self.reference_node); // Still need to verify as last may be first as well
+            }
+        }
+        if (self.reference_node == self.root) return null;
+
+        var current = self.reference_node;
+        while (try parser.nodePreviousSibling(current)) |previous| {
+            current = previous;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => {
+                    // Get last child if it has one.
+                    if (try self.lastChild(current)) |child| {
+                        self.reference_node = child;
+                        return try Node.toInterface(child);
+                    }
+
+                    // Otherwise, this node is our previous one.
+                    self.reference_node = current;
+                    return try Node.toInterface(current);
+                },
+                .reject, .skip => {
+                    // Get last child if it has one.
+                    if (try self.lastChild(current)) |child| {
+                        self.reference_node = child;
+                        return try Node.toInterface(child);
+                    }
+                },
+            }
+        }
+
+        if (current != self.root) {
+            if (try self.parentNode(current)) |parent| {
+                self.reference_node = parent;
+                return try Node.toInterface(parent);
+            }
+        }
+
+        return null;
+    }
+
+    fn firstChild(self: *const NodeIterator, node: *parser.Node) !?*parser.Node {
+        const children = try parser.nodeGetChildNodes(node);
+        const child_count = try parser.nodeListLength(children);
+
+        for (0..child_count) |i| {
+            const index: u32 = @intCast(i);
+            const child = (try parser.nodeListItem(children, index)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, child)) {
+                .accept => return child, // NOTE: Skip and reject are equivalent for NodeIterator, this is different from TreeWalker
+                .reject, .skip => if (try self.firstChild(child)) |gchild| return gchild,
+            }
+        }
+
+        return null;
+    }
+
+    fn lastChild(self: *const NodeIterator, node: *parser.Node) !?*parser.Node {
+        const children = try parser.nodeGetChildNodes(node);
+        const child_count = try parser.nodeListLength(children);
+
+        var index: u32 = child_count;
+        while (index > 0) {
+            index -= 1;
+            const child = (try parser.nodeListItem(children, index)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, child)) {
+                .accept => return child, // NOTE: Skip and reject are equivalent for NodeIterator, this is different from TreeWalker
+                .reject, .skip => if (try self.lastChild(child)) |gchild| return gchild,
+            }
+        }
+
+        return null;
+    }
+
+    // This implementation is actually the same as :TreeWalker
+    fn parentNode(self: *const NodeIterator, node: *parser.Node) !?*parser.Node {
+        if (self.root == node) return null;
+
+        var current = node;
+        while (true) {
+            if (current == self.root) return null;
+            current = (try parser.nodeParentNode(current)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => return current,
+                .reject, .skip => continue,
+            }
+        }
+    }
+
+    // This implementation is actually the same as :TreeWalker
+    fn nextSibling(self: *const NodeIterator, node: *parser.Node) !?*parser.Node {
+        var current = node;
+
+        while (true) {
+            current = (try parser.nodeNextSibling(current)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => return current,
+                .skip, .reject => continue,
+            }
+        }
+
+        return null;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.NodeFilter" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{
+            \\ const nodeIterator = document.createNodeIterator(
+            \\   document.body,
+            \\   NodeFilter.SHOW_ELEMENT,
+            \\   {
+            \\     acceptNode(node) {
+            \\       return NodeFilter.FILTER_ACCEPT;
+            \\     },
+            \\   },
+            \\ );
+            \\ nodeIterator.nextNode().nodeName;
+            ,
+            "BODY",
+        },
+        .{ "nodeIterator.nextNode().nodeName", "DIV" },
+        .{ "nodeIterator.nextNode().nodeName", "A" },
+        .{ "nodeIterator.previousNode().nodeName", "A" }, // pointer_before_current flips
+        .{ "nodeIterator.nextNode().nodeName", "A" }, // pointer_before_current flips
+        .{ "nodeIterator.previousNode().nodeName", "A" }, // pointer_before_current flips
+        .{ "nodeIterator.previousNode().nodeName", "DIV" },
+        .{ "nodeIterator.previousNode().nodeName", "BODY" },
+        .{ "nodeIterator.previousNode()", "null" }, // Not HEAD since body is root
+        .{ "nodeIterator.previousNode()", "null" }, // Keeps returning null
+        .{ "nodeIterator.nextNode().nodeName", "BODY" },
+
+        .{ "nodeIterator.nextNode().nodeName", null },
+        .{ "nodeIterator.nextNode().nodeName", null },
+        .{ "nodeIterator.nextNode().nodeName", null },
+        .{ "nodeIterator.nextNode().nodeName", "SPAN" },
+        .{ "nodeIterator.nextNode().nodeName", "P" },
+        .{ "nodeIterator.nextNode()", "null" }, // Just the last one
+        .{ "nodeIterator.nextNode()", "null" }, // Keeps returning null
+        .{ "nodeIterator.previousNode().nodeName", "P" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ const notationIterator = document.createNodeIterator(
+            \\   document.body,
+            \\   NodeFilter.SHOW_NOTATION,
+            \\ );
+            \\ notationIterator.nextNode();
+            ,
+            "null",
+        },
+        .{ "notationIterator.previousNode()", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nodeIterator.filter.acceptNode(document.body)", "1" },
+        .{ "notationIterator.filter", "null" },
+        .{
+            \\ const rejectIterator = document.createNodeIterator(
+            \\   document.body,
+            \\   NodeFilter.SHOW_ALL,
+            \\   (e => { return NodeFilter.FILTER_REJECT}),
+            \\ );
+            \\ rejectIterator.filter(document.body);
+            ,
+            "2",
+        },
+    }, .{});
+}
--- a/src/browser/dom/nodelist.zig
+++ b/src/browser/dom/nodelist.zig
@@ -0,0 +1,198 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+
+const JsThis = @import("../env.zig").JsThis;
+const Function = @import("../env.zig").Function;
+
+const NodeUnion = @import("node.zig").Union;
+const Node = @import("node.zig").Node;
+
+const U32Iterator = @import("../iterator/iterator.zig").U32Iterator;
+
+const DOMException = @import("exceptions.zig").DOMException;
+
+pub const Interfaces = .{
+    NodeListIterator,
+    NodeList,
+};
+
+pub const NodeListIterator = struct {
+    coll: *NodeList,
+    index: u32 = 0,
+
+    pub const Return = struct {
+        value: ?NodeUnion,
+        done: bool,
+    };
+
+    pub fn _next(self: *NodeListIterator) !Return {
+        const e = try self.coll._item(self.index);
+        if (e == null) {
+            return Return{
+                .value = null,
+                .done = true,
+            };
+        }
+
+        self.index += 1;
+        return Return{
+            .value = e,
+            .done = false,
+        };
+    }
+};
+
+pub const NodeListEntriesIterator = struct {
+    coll: *NodeList,
+    index: u32 = 0,
+
+    pub const Return = struct {
+        value: ?NodeUnion,
+        done: bool,
+    };
+
+    pub fn _next(self: *NodeListEntriesIterator) !Return {
+        const e = try self.coll._item(self.index);
+        if (e == null) {
+            return Return{
+                .value = null,
+                .done = true,
+            };
+        }
+
+        self.index += 1;
+        return Return{
+            .value = e,
+            .done = false,
+        };
+    }
+};
+
+// Nodelist is implemented in pure Zig b/c libdom's NodeList doesn't allow to
+// append nodes.
+// WEB IDL https://dom.spec.whatwg.org/#nodelist
+//
+// TODO: a Nodelist can be either static or live. But the current
+// implementation allows only static nodelist.
+// see https://dom.spec.whatwg.org/#old-style-collections
+pub const NodeList = struct {
+    pub const Exception = DOMException;
+    const NodesArrayList = std.ArrayListUnmanaged(*parser.Node);
+
+    nodes: NodesArrayList = .{},
+
+    pub fn deinit(self: *NodeList, alloc: std.mem.Allocator) void {
+        // TODO unref all nodes
+        self.nodes.deinit(alloc);
+    }
+
+    pub fn append(self: *NodeList, alloc: std.mem.Allocator, node: *parser.Node) !void {
+        try self.nodes.append(alloc, node);
+    }
+
+    pub fn get_length(self: *NodeList) u32 {
+        return @intCast(self.nodes.items.len);
+    }
+
+    pub fn _item(self: *const NodeList, index: u32) !?NodeUnion {
+        if (index >= self.nodes.items.len) {
+            return null;
+        }
+
+        const n = self.nodes.items[index];
+        return try Node.toInterface(n);
+    }
+
+    // This code works, but it's _MUCH_ slower than using postAttach. The benefit
+    // of this version, is that it's "live"..but we're talking many orders of
+    // magnitude slower.
+    //
+    // You can test it by commenting out `postAttach`, uncommenting this and
+    // running:
+    //    zig build wpt --  tests/wpt/dom/nodes/NodeList-static-length-getter-tampered-indexOf-1.html
+    //
+    // I think this _is_ the right way to do it, but I must be doing something
+    // wrong to make it so slow.
+    // pub fn indexed_get(self: *const NodeList, index: u32, has_value: *bool) !?NodeUnion {
+    //     return (try self._item(index)) orelse {
+    //         has_value.* = false;
+    //         return null;
+    //     };
+    // }
+
+    pub fn _forEach(self: *NodeList, cbk: Function) !void { // TODO handle thisArg
+        for (self.nodes.items, 0..) |n, i| {
+            const ii: u32 = @intCast(i);
+            var result: Function.Result = undefined;
+            cbk.tryCall(void, .{ n, ii, self }, &result) catch {
+                log.debug(.user_script, "forEach callback", .{ .err = result.exception, .stack = result.stack });
+            };
+        }
+    }
+
+    pub fn _keys(self: *NodeList) U32Iterator {
+        return .{
+            .length = self.get_length(),
+        };
+    }
+
+    pub fn _values(self: *NodeList) NodeListIterator {
+        return .{
+            .coll = self,
+        };
+    }
+
+    pub fn _symbol_iterator(self: *NodeList) NodeListIterator {
+        return self._values();
+    }
+
+    // TODO entries() https://developer.mozilla.org/en-US/docs/Web/API/NodeList/entries
+    pub fn postAttach(self: *NodeList, js_this: JsThis) !void {
+        const len = self.get_length();
+        for (0..len) |i| {
+            const node = try self._item(@intCast(i)) orelse unreachable;
+            try js_this.setIndex(@intCast(i), node, .{});
+        }
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.NodeList" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let list = document.getElementById('content').childNodes", "undefined" },
+        .{ "list.length", "9" },
+        .{ "list[0].__proto__.constructor.name", "Text" },
+        .{
+            \\  let i = 0;
+            \\  list.forEach(function (n, idx) {
+            \\    i += idx;
+            \\  });
+            \\  i;
+            ,
+            "36",
+        },
+    }, .{});
+}
--- a/src/browser/dom/performance.zig
+++ b/src/browser/dom/performance.zig
@@ -0,0 +1,214 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+const Env = @import("../env.zig").Env;
+const Page = @import("../page.zig").Page;
+
+pub const Interfaces = .{
+    Performance,
+    PerformanceEntry,
+    PerformanceMark,
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/Performance
+pub const Performance = struct {
+    pub const prototype = *EventTarget;
+
+    // Extend libdom event target for pure zig struct.
+    base: parser.EventTargetTBase = parser.EventTargetTBase{ .internal_target_type = .performance },
+
+    time_origin: std.time.Timer,
+    // if (Window.crossOriginIsolated) -> Resolution in isolated contexts:       5 microseconds
+    // else                            -> Resolution in non-isolated contexts: 100 microseconds
+    const ms_resolution = 100;
+
+    fn limitedResolutionMs(nanoseconds: u64) f64 {
+        const elapsed_at_resolution = ((nanoseconds / std.time.ns_per_us) + ms_resolution / 2) / ms_resolution * ms_resolution;
+        const elapsed = @as(f64, @floatFromInt(elapsed_at_resolution));
+        return elapsed / @as(f64, std.time.us_per_ms);
+    }
+
+    pub fn get_timeOrigin(self: *const Performance) f64 {
+        const is_posix = switch (@import("builtin").os.tag) { // From std.time.zig L125
+            .windows, .uefi, .wasi => false,
+            else => true,
+        };
+        const zero = std.time.Instant{ .timestamp = if (!is_posix) 0 else .{ .sec = 0, .nsec = 0 } };
+        const started = self.time_origin.started.since(zero);
+        return limitedResolutionMs(started);
+    }
+
+    pub fn _now(self: *Performance) f64 {
+        return limitedResolutionMs(self.time_origin.read());
+    }
+
+    pub fn _mark(_: *Performance, name: []const u8, _options: ?PerformanceMark.Options, page: *Page) !PerformanceMark {
+        const mark: PerformanceMark = try .constructor(name, _options, page);
+        // TODO: Should store this in an entries list
+        return mark;
+    }
+
+    // TODO: fn _mark should record the marks in a lookup
+    pub fn _clearMarks(_: *Performance, name: ?[]const u8) void {
+        _ = name;
+    }
+
+    // TODO: fn _measures should record the marks in a lookup
+    pub fn _clearMeasures(_: *Performance, name: ?[]const u8) void {
+        _ = name;
+    }
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/PerformanceEntry
+pub const PerformanceEntry = struct {
+    const PerformanceEntryType = enum {
+        element,
+        event,
+        first_input,
+        largest_contentful_paint,
+        layout_shift,
+        long_animation_frame,
+        longtask,
+        mark,
+        measure,
+        navigation,
+        paint,
+        resource,
+        taskattribution,
+        visibility_state,
+
+        pub fn toString(self: PerformanceEntryType) []const u8 {
+            return switch (self) {
+                .first_input => "first-input",
+                .largest_contentful_paint => "largest-contentful-paint",
+                .layout_shift => "layout-shift",
+                .long_animation_frame => "long-animation-frame",
+                .visibility_state => "visibility-state",
+                else => @tagName(self),
+            };
+        }
+    };
+
+    duration: f64 = 0.0,
+    entry_type: PerformanceEntryType,
+    name: []const u8,
+    start_time: f64 = 0.0,
+
+    pub fn get_duration(self: *const PerformanceEntry) f64 {
+        return self.duration;
+    }
+
+    pub fn get_entryType(self: *const PerformanceEntry) PerformanceEntryType {
+        return self.entry_type;
+    }
+
+    pub fn get_name(self: *const PerformanceEntry) []const u8 {
+        return self.name;
+    }
+
+    pub fn get_startTime(self: *const PerformanceEntry) f64 {
+        return self.start_time;
+    }
+};
+
+// https://developer.mozilla.org/en-US/docs/Web/API/PerformanceMark
+pub const PerformanceMark = struct {
+    pub const prototype = *PerformanceEntry;
+
+    proto: PerformanceEntry,
+    detail: ?Env.JsObject,
+
+    const Options = struct {
+        detail: ?Env.JsObject = null,
+        start_time: ?f64 = null,
+    };
+
+    pub fn constructor(name: []const u8, _options: ?Options, page: *Page) !PerformanceMark {
+        const perf = &page.window.performance;
+
+        const options = _options orelse Options{};
+        const start_time = options.start_time orelse perf._now();
+
+        if (start_time < 0.0) {
+            return error.TypeError;
+        }
+
+        const detail = if (options.detail) |d| try d.persist() else null;
+
+        const duped_name = try page.arena.dupe(u8, name);
+        const proto = PerformanceEntry{ .name = duped_name, .entry_type = .mark, .start_time = start_time };
+
+        return .{ .proto = proto, .detail = detail };
+    }
+
+    pub fn get_detail(self: *const PerformanceMark) ?Env.JsObject {
+        return self.detail;
+    }
+};
+
+const testing = @import("./../../testing.zig");
+
+test "Performance: get_timeOrigin" {
+    var perf = Performance{ .time_origin = try std.time.Timer.start() };
+    const time_origin = perf.get_timeOrigin();
+    try testing.expect(time_origin >= 0);
+
+    // Check resolution
+    try testing.expectDelta(@rem(time_origin * std.time.us_per_ms, 100.0), 0.0, 0.2);
+}
+
+test "Performance: now" {
+    var perf = Performance{ .time_origin = try std.time.Timer.start() };
+
+    // Monotonically increasing
+    var now = perf._now();
+    while (now <= 0) { // Loop for now to not be 0
+        try testing.expectEqual(now, 0);
+        now = perf._now();
+    }
+    // Check resolution
+    try testing.expectDelta(@rem(now * std.time.us_per_ms, 100.0), 0.0, 0.1);
+
+    var after = perf._now();
+    while (after <= now) { // Loop untill after > now
+        try testing.expectEqual(after, now);
+        after = perf._now();
+    }
+    // Check resolution
+    try testing.expectDelta(@rem(after * std.time.us_per_ms, 100.0), 0.0, 0.1);
+}
+
+test "Browser.Performance.Mark" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let performance = window.performance", "undefined" },
+        .{ "performance instanceof Performance", "true" },
+        .{ "let mark = performance.mark(\"start\")", "undefined" },
+        .{ "mark instanceof PerformanceMark", "true" },
+        .{ "mark.name", "start" },
+        .{ "mark.entryType", "mark" },
+        .{ "mark.duration", "0" },
+        .{ "mark.detail", "null" },
+    }, .{});
+}
--- a/src/browser/dom/performance_observer.zig
+++ b/src/browser/dom/performance_observer.zig
@@ -0,0 +1,63 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Env = @import("../env.zig").Env;
+
+const PerformanceEntry = @import("performance.zig").PerformanceEntry;
+
+// https://developer.mozilla.org/en-US/docs/Web/API/PerformanceObserver
+pub const PerformanceObserver = struct {
+    pub const _supportedEntryTypes = [0][]const u8{};
+
+    pub fn constructor(cbk: Env.Function) PerformanceObserver {
+        _ = cbk;
+        return .{};
+    }
+
+    pub fn _observe(self: *const PerformanceObserver, options_: ?Options) void {
+        _ = self;
+        _ = options_;
+        return;
+    }
+
+    pub fn _disconnect(self: *PerformanceObserver) void {
+        _ = self;
+    }
+
+    pub fn _takeRecords(_: *const PerformanceObserver) []PerformanceEntry {
+        return &[_]PerformanceEntry{};
+    }
+};
+
+const Options = struct {
+    buffered: ?bool = null,
+    durationThreshold: ?f64 = null,
+    entryTypes: ?[]const []const u8 = null,
+    type: ?[]const u8 = null,
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.PerformanceObserver" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "PerformanceObserver.supportedEntryTypes.length", "0" },
+    }, .{});
+}
--- a/src/browser/dom/processing_instruction.zig
+++ b/src/browser/dom/processing_instruction.zig
@@ -0,0 +1,116 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+const Node = @import("node.zig").Node;
+const Page = @import("../page.zig").Page;
+
+// https://dom.spec.whatwg.org/#processinginstruction
+pub const ProcessingInstruction = struct {
+    pub const Self = parser.ProcessingInstruction;
+
+    // TODO for libdom processing instruction inherit from node.
+    // But the spec says it must inherit from CDATA.
+    pub const prototype = *Node;
+    pub const subtype = .node;
+
+    pub fn get_target(self: *parser.ProcessingInstruction) ![]const u8 {
+        // libdom stores the ProcessingInstruction target in the node's name.
+        return try parser.nodeName(parser.processingInstructionToNode(self));
+    }
+
+    // There's something wrong when we try to clone a ProcessInstruction normally.
+    // The resulting object can't be cast back into a node (it crashes). This is
+    // a simple workaround.
+    pub fn _cloneNode(self: *parser.ProcessingInstruction, _: ?bool, page: *Page) !*parser.ProcessingInstruction {
+        return try parser.documentCreateProcessingInstruction(
+            @ptrCast(page.window.document),
+            try get_target(self),
+            (try get_data(self)) orelse "",
+        );
+    }
+
+    pub fn get_data(self: *parser.ProcessingInstruction) !?[]const u8 {
+        return try parser.nodeValue(parser.processingInstructionToNode(self));
+    }
+
+    pub fn set_data(self: *parser.ProcessingInstruction, data: []u8) !void {
+        try parser.nodeSetValue(parser.processingInstructionToNode(self), data);
+    }
+
+    // netsurf's ProcessInstruction doesn't implement the dom_node_get_attributes
+    // and thus will crash if we try to call nodeIsEqualNode.
+    pub fn _isEqualNode(self: *parser.ProcessingInstruction, other_node: *parser.Node) !bool {
+        if (try parser.nodeType(other_node) != .processing_instruction) {
+            return false;
+        }
+
+        const other: *parser.ProcessingInstruction = @ptrCast(other_node);
+
+        if (std.mem.eql(u8, try get_target(self), try get_target(other)) == false) {
+            return false;
+        }
+
+        {
+            const self_data = try get_data(self);
+            const other_data = try get_data(other);
+            if (self_data == null and other_data != null) {
+                return false;
+            }
+            if (self_data != null and other_data == null) {
+                return false;
+            }
+            if (std.mem.eql(u8, self_data.?, other_data.?) == false) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.ProcessingInstruction" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let pi = document.createProcessingInstruction('foo', 'bar')", "undefined" },
+        .{ "pi.target", "foo" },
+        .{ "pi.data", "bar" },
+        .{ "pi.data = 'foo'", "foo" },
+        .{ "pi.data", "foo" },
+
+        .{ "let pi2 = pi.cloneNode()", "undefined" },
+        .{ "pi2.nodeType", "7" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let pi11 = document.createProcessingInstruction('target1', 'data1');", "undefined" },
+        .{ "let pi12 = document.createProcessingInstruction('target2', 'data2');", "undefined" },
+        .{ "let pi13 = document.createProcessingInstruction('target1', 'data1');", "undefined" },
+        .{ "pi11.isEqualNode(pi11)", "true" },
+        .{ "pi11.isEqualNode(pi13)", "true" },
+        .{ "pi11.isEqualNode(pi12)", "false" },
+        .{ "pi12.isEqualNode(pi13)", "false" },
+        .{ "pi11.isEqualNode(document)", "false" },
+        .{ "document.isEqualNode(pi11)", "false" },
+    }, .{});
+}
--- a/src/browser/dom/range.zig
+++ b/src/browser/dom/range.zig
@@ -0,0 +1,178 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const NodeUnion = @import("node.zig").Union;
+const Node = @import("node.zig").Node;
+
+pub const Interfaces = .{
+    AbstractRange,
+    Range,
+};
+
+pub const AbstractRange = struct {
+    collapsed: bool,
+    end_container: *parser.Node,
+    end_offset: i32,
+    start_container: *parser.Node,
+    start_offset: i32,
+
+    pub fn updateCollapsed(self: *AbstractRange) void {
+        // TODO: Eventually, compare properly.
+        self.collapsed = false;
+    }
+
+    pub fn get_collapsed(self: *const AbstractRange) bool {
+        return self.collapsed;
+    }
+
+    pub fn get_endContainer(self: *const AbstractRange) !NodeUnion {
+        return Node.toInterface(self.end_container);
+    }
+
+    pub fn get_endOffset(self: *const AbstractRange) i32 {
+        return self.end_offset;
+    }
+
+    pub fn get_startContainer(self: *const AbstractRange) !NodeUnion {
+        return Node.toInterface(self.start_container);
+    }
+
+    pub fn get_startOffset(self: *const AbstractRange) i32 {
+        return self.start_offset;
+    }
+};
+
+pub const Range = struct {
+    pub const prototype = *AbstractRange;
+
+    proto: AbstractRange,
+
+    // The Range() constructor returns a newly created Range object whose start
+    // and end is the global Document object.
+    // https://developer.mozilla.org/en-US/docs/Web/API/Range/Range
+    pub fn constructor(page: *Page) Range {
+        const proto: AbstractRange = .{
+            .collapsed = true,
+            .end_container = parser.documentHTMLToNode(page.window.document),
+            .end_offset = 0,
+            .start_container = parser.documentHTMLToNode(page.window.document),
+            .start_offset = 0,
+        };
+
+        return .{ .proto = proto };
+    }
+
+    pub fn _setStart(self: *Range, node: *parser.Node, offset: i32) void {
+        self.proto.start_container = node;
+        self.proto.start_offset = offset;
+        self.proto.updateCollapsed();
+    }
+
+    pub fn _setEnd(self: *Range, node: *parser.Node, offset: i32) void {
+        self.proto.end_container = node;
+        self.proto.end_offset = offset;
+        self.proto.updateCollapsed();
+    }
+
+    pub fn _createContextualFragment(_: *Range, fragment: []const u8, page: *Page) !*parser.DocumentFragment {
+        const document_html = page.window.document;
+        const document = parser.documentHTMLToDocument(document_html);
+        const doc_frag = try parser.documentParseFragmentFromStr(document, fragment);
+        return doc_frag;
+    }
+
+    pub fn _selectNodeContents(self: *Range, node: *parser.Node) !void {
+        self.proto.start_container = node;
+        self.proto.start_offset = 0;
+        self.proto.end_container = node;
+
+        // Set end_offset
+        switch (try parser.nodeType(node)) {
+            .text, .cdata_section, .comment, .processing_instruction => {
+                // For text-like nodes, end_offset should be the length of the text data
+                if (try parser.nodeValue(node)) |text_data| {
+                    self.proto.end_offset = @intCast(text_data.len);
+                } else {
+                    self.proto.end_offset = 0;
+                }
+            },
+            else => {
+                // For element and other nodes, end_offset is the number of children
+                const child_nodes = try parser.nodeGetChildNodes(node);
+                const child_count = try parser.nodeListLength(child_nodes);
+                self.proto.end_offset = @intCast(child_count);
+            },
+        }
+
+        self.proto.updateCollapsed();
+    }
+
+    // The Range.detach() method does nothing. It used to disable the Range
+    // object and enable the browser to release associated resources. The
+    // method has been kept for compatibility.
+    // https://developer.mozilla.org/en-US/docs/Web/API/Range/detach
+    pub fn _detach(_: *Range) void {}
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.Range" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        // Test Range constructor
+        .{ "let range = new Range()", "undefined" },
+        .{ "range instanceof Range", "true" },
+        .{ "range instanceof AbstractRange", "true" },
+
+        // Test initial state - collapsed range
+        .{ "range.collapsed", "true" },
+        .{ "range.startOffset", "0" },
+        .{ "range.endOffset", "0" },
+        .{ "range.startContainer instanceof HTMLDocument", "true" },
+        .{ "range.endContainer instanceof HTMLDocument", "true" },
+
+        // Test document.createRange()
+        .{ "let docRange = document.createRange()", "undefined" },
+        .{ "docRange instanceof Range", "true" },
+        .{ "docRange.collapsed", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const container = document.getElementById('content');", null },
+
+        // Test text range
+        .{ "const commentNode = container.childNodes[7];", null },
+        .{ "commentNode.nodeValue", "comment" },
+        .{ "const textRange = document.createRange();", null },
+        .{ "textRange.selectNodeContents(commentNode)", "undefined" },
+        .{ "textRange.startOffset", "0" },
+        .{ "textRange.endOffset", "7" }, // length of `comment`
+
+        // Test Node range
+        .{ "const nodeRange = document.createRange();", null },
+        .{ "nodeRange.selectNodeContents(container)", "undefined" },
+        .{ "nodeRange.startOffset", "0" },
+        .{ "nodeRange.endOffset", "9" }, // length of container.childNodes
+    }, .{});
+}
--- a/src/browser/dom/resize_observer.zig
+++ b/src/browser/dom/resize_observer.zig
@@ -0,0 +1,54 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const Env = @import("../env.zig").Env;
+const parser = @import("../netsurf.zig");
+
+pub const Interfaces = .{
+    ResizeObserver,
+};
+
+// WEB IDL https://drafts.csswg.org/resize-observer/#resize-observer-interface
+pub const ResizeObserver = struct {
+    pub fn constructor(cbk: Env.Function) ResizeObserver {
+        _ = cbk;
+        return .{};
+    }
+
+    pub fn _observe(self: *const ResizeObserver, element: *parser.Element, options_: ?Options) void {
+        _ = self;
+        _ = element;
+        _ = options_;
+        return;
+    }
+
+    pub fn _unobserve(self: *const ResizeObserver, element: *parser.Element) void {
+        _ = self;
+        _ = element;
+        return;
+    }
+
+    // TODO
+    pub fn _disconnect(self: *ResizeObserver) void {
+        _ = self;
+    }
+};
+
+const Options = struct {
+    box: []const u8,
+};
--- a/src/browser/dom/shadow_root.zig
+++ b/src/browser/dom/shadow_root.zig
@@ -0,0 +1,73 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+const Element = @import("element.zig").Element;
+const ElementUnion = @import("element.zig").Union;
+
+// WEB IDL https://dom.spec.whatwg.org/#interface-shadowroot
+pub const ShadowRoot = struct {
+    pub const prototype = *parser.DocumentFragment;
+    pub const subtype = .node;
+
+    mode: Mode,
+    host: *parser.Element,
+    proto: *parser.DocumentFragment,
+
+    pub const Mode = enum {
+        open,
+        closed,
+    };
+
+    pub fn get_host(self: *const ShadowRoot) !ElementUnion {
+        return Element.toInterface(self.host);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.ShadowRoot" {
+    defer testing.reset();
+
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{ .html = "" });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "const div1 = document.createElement('div');", null },
+        .{ "let sr1 = div1.attachShadow({mode: 'open'})", null },
+        .{ "sr1.host == div1", "true" },
+        .{ "div1.attachShadow({mode: 'open'}) == sr1", "true" },
+        .{ "div1.shadowRoot == sr1", "true" },
+
+        .{ "try { div1.attachShadow({mode: 'closed'}) } catch (e) { e }", "Error: NotSupportedError" },
+
+        .{ " sr1.append(document.createElement('div'))", null },
+        .{ " sr1.append(document.createElement('span'))", null },
+        .{ "sr1.childElementCount", "2" },
+        // re-attaching clears it
+        .{ "div1.attachShadow({mode: 'open'}) == sr1", "true" },
+        .{ "sr1.childElementCount", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "const div2 = document.createElement('di2');", null },
+        .{ "let sr2 = div2.attachShadow({mode: 'closed'})", null },
+        .{ "sr2.host == div2", "true" },
+        .{ "div2.shadowRoot", "null" }, // null when attached with 'closed'
+    }, .{});
+}
--- a/src/browser/dom/text.zig
+++ b/src/browser/dom/text.zig
@@ -0,0 +1,86 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const CharacterData = @import("character_data.zig").CharacterData;
+const CDATASection = @import("cdata_section.zig").CDATASection;
+
+// Text interfaces
+pub const Interfaces = .{
+    CDATASection,
+};
+
+pub const Text = struct {
+    pub const Self = parser.Text;
+    pub const prototype = *CharacterData;
+    pub const subtype = .node;
+
+    pub fn constructor(data: ?[]const u8, page: *const Page) !*parser.Text {
+        return parser.documentCreateTextNode(
+            parser.documentHTMLToDocument(page.window.document),
+            data orelse "",
+        );
+    }
+
+    // JS funcs
+    // --------
+
+    // Read attributes
+
+    pub fn get_wholeText(self: *parser.Text) ![]const u8 {
+        return try parser.textWholdeText(self);
+    }
+
+    // JS methods
+    // ----------
+
+    pub fn _splitText(self: *parser.Text, offset: u32) !*parser.Text {
+        return try parser.textSplitText(self, offset);
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.Text" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let t = new Text('foo')", "undefined" },
+        .{ "t.data", "foo" },
+
+        .{ "let emptyt = new Text()", "undefined" },
+        .{ "emptyt.data", "" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let text = document.getElementById('link').firstChild", "undefined" },
+        .{ "text.wholeText === 'OK'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "text.data = 'OK modified'", "OK modified" },
+        .{ "let split = text.splitText('OK'.length)", "undefined" },
+        .{ "split.data === ' modified'", "true" },
+        .{ "text.data === 'OK'", "true" },
+    }, .{});
+}
--- a/src/browser/dom/token_list.zig
+++ b/src/browser/dom/token_list.zig
@@ -0,0 +1,245 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const iterator = @import("../iterator/iterator.zig");
+
+const Function = @import("../env.zig").Function;
+const JsObject = @import("../env.zig").JsObject;
+const DOMException = @import("exceptions.zig").DOMException;
+
+pub const Interfaces = .{
+    DOMTokenList,
+    DOMTokenListIterable,
+    TokenListEntriesIterator,
+    TokenListEntriesIterator.Iterable,
+};
+
+// https://dom.spec.whatwg.org/#domtokenlist
+pub const DOMTokenList = struct {
+    pub const Self = parser.TokenList;
+    pub const Exception = DOMException;
+
+    pub fn get_length(self: *parser.TokenList) !u32 {
+        return parser.tokenListGetLength(self);
+    }
+
+    pub fn _item(self: *parser.TokenList, index: u32) !?[]const u8 {
+        return parser.tokenListItem(self, index);
+    }
+
+    pub fn _contains(self: *parser.TokenList, token: []const u8) !bool {
+        return parser.tokenListContains(self, token);
+    }
+
+    pub fn _add(self: *parser.TokenList, tokens: []const []const u8) !void {
+        for (tokens) |token| {
+            try parser.tokenListAdd(self, token);
+        }
+    }
+
+    pub fn _remove(self: *parser.TokenList, tokens: []const []const u8) !void {
+        for (tokens) |token| {
+            try parser.tokenListRemove(self, token);
+        }
+    }
+
+    /// If token is the empty string, then throw a "SyntaxError" DOMException.
+    /// If token contains any ASCII whitespace, then throw an
+    /// "InvalidCharacterError" DOMException.
+    fn validateToken(token: []const u8) !void {
+        if (token.len == 0) {
+            return parser.DOMError.Syntax;
+        }
+        for (token) |c| {
+            if (std.ascii.isWhitespace(c)) return parser.DOMError.InvalidCharacter;
+        }
+    }
+
+    pub fn _toggle(self: *parser.TokenList, token: []const u8, force: ?bool) !bool {
+        try validateToken(token);
+        const exists = try parser.tokenListContains(self, token);
+        if (exists) {
+            if (force == null or force.? == false) {
+                try parser.tokenListRemove(self, token);
+                return false;
+            }
+            return true;
+        }
+
+        if (force == null or force.? == true) {
+            try parser.tokenListAdd(self, token);
+            return true;
+        }
+        return false;
+    }
+
+    pub fn _replace(self: *parser.TokenList, token: []const u8, new: []const u8) !bool {
+        try validateToken(token);
+        try validateToken(new);
+        const exists = try parser.tokenListContains(self, token);
+        if (!exists) return false;
+        try parser.tokenListRemove(self, token);
+        try parser.tokenListAdd(self, new);
+        return true;
+    }
+
+    // TODO to implement.
+    pub fn _supports(_: *parser.TokenList, token: []const u8) !bool {
+        try validateToken(token);
+        return error.TypeError;
+    }
+
+    pub fn get_value(self: *parser.TokenList) !?[]const u8 {
+        return (try parser.tokenListGetValue(self)) orelse "";
+    }
+
+    pub fn set_value(self: *parser.TokenList, value: []const u8) !void {
+        return parser.tokenListSetValue(self, value);
+    }
+
+    pub fn _toString(self: *parser.TokenList) ![]const u8 {
+        return (try get_value(self)) orelse "";
+    }
+
+    pub fn _keys(self: *parser.TokenList) !iterator.U32Iterator {
+        return .{ .length = try get_length(self) };
+    }
+
+    pub fn _values(self: *parser.TokenList) DOMTokenListIterable {
+        return DOMTokenListIterable.init(.{ .token_list = self });
+    }
+
+    pub fn _entries(self: *parser.TokenList) TokenListEntriesIterator {
+        return TokenListEntriesIterator.init(.{ .token_list = self });
+    }
+
+    pub fn _symbol_iterator(self: *parser.TokenList) DOMTokenListIterable {
+        return _values(self);
+    }
+
+    // TODO handle thisArg
+    pub fn _forEach(self: *parser.TokenList, cbk: Function, this_arg: JsObject) !void {
+        var entries = _entries(self);
+        while (try entries._next()) |entry| {
+            var result: Function.Result = undefined;
+            cbk.tryCallWithThis(void, this_arg, .{ entry.@"1", entry.@"0", self }, &result) catch {
+                log.debug(.user_script, "callback error", .{
+                    .err = result.exception,
+                    .stack = result.stack,
+                    .soure = "tokenList foreach",
+                });
+            };
+        }
+    }
+};
+
+const DOMTokenListIterable = iterator.Iterable(Iterator, "DOMTokenListIterable");
+const TokenListEntriesIterator = iterator.NumericEntries(Iterator, "TokenListEntriesIterator");
+
+pub const Iterator = struct {
+    index: u32 = 0,
+    token_list: *parser.TokenList,
+
+    // used when wrapped in an iterator.NumericEntries
+    pub const Error = parser.DOMError;
+
+    pub fn _next(self: *Iterator) !?[]const u8 {
+        const index = self.index;
+        self.index = index + 1;
+        return DOMTokenList._item(self.token_list, index);
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.DOM.TokenList" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let gs = document.getElementById('para-empty')", "undefined" },
+        .{ "let cl = gs.classList", "undefined" },
+        .{ "gs.className", "ok empty" },
+        .{ "cl.value", "ok empty" },
+        .{ "cl.length", "2" },
+        .{ "gs.className = 'foo bar baz'", "foo bar baz" },
+        .{ "gs.className", "foo bar baz" },
+        .{ "cl.length", "3" },
+        .{ "gs.className = 'ok empty'", "ok empty" },
+        .{ "cl.length", "2" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let cl2 = gs.classList", "undefined" },
+        .{ "cl2.length", "2" },
+        .{ "cl2.item(0)", "ok" },
+        .{ "cl2.item(1)", "empty" },
+        .{ "cl2.contains('ok')", "true" },
+        .{ "cl2.contains('nok')", "false" },
+        .{ "cl2.add('foo', 'bar', 'baz')", "undefined" },
+        .{ "cl2.length", "5" },
+        .{ "cl2.remove('foo', 'bar', 'baz')", "undefined" },
+        .{ "cl2.length", "2" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let cl3 = gs.classList", "undefined" },
+        .{ "cl3.toggle('ok')", "false" },
+        .{ "cl3.toggle('ok')", "true" },
+        .{ "cl3.length", "2" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let cl4 = gs.classList", "undefined" },
+        .{ "cl4.replace('ok', 'nok')", "true" },
+        .{ "cl4.value", "empty nok" },
+        .{ "cl4.replace('nok', 'ok')", "true" },
+        .{ "cl4.value", "empty ok" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let cl5 = gs.classList", "undefined" },
+        .{ "let keys = [...cl5.keys()]", "undefined" },
+        .{ "keys.length", "2" },
+        .{ "keys[0]", "0" },
+        .{ "keys[1]", "1" },
+
+        .{ "let values = [...cl5.values()]", "undefined" },
+        .{ "values.length", "2" },
+        .{ "values[0]", "empty" },
+        .{ "values[1]", "ok" },
+
+        .{ "let entries = [...cl5.entries()]", "undefined" },
+        .{ "entries.length", "2" },
+        .{ "entries[0]", "0,empty" },
+        .{ "entries[1]", "1,ok" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "let cl6 = gs.classList", "undefined" },
+        .{ "cl6.value = 'a  b  ccc'", "a  b  ccc" },
+        .{ "cl6.value", "a  b  ccc" },
+        .{ "cl6.toString()", "a  b  ccc" },
+    }, .{});
+}
--- a/src/browser/dom/tree_walker.zig
+++ b/src/browser/dom/tree_walker.zig
@@ -0,0 +1,265 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+
+const NodeFilter = @import("node_filter.zig");
+const Env = @import("../env.zig").Env;
+const Page = @import("../page.zig").Page;
+const Node = @import("node.zig").Node;
+const NodeUnion = @import("node.zig").Union;
+
+// https://developer.mozilla.org/en-US/docs/Web/API/TreeWalker
+pub const TreeWalker = struct {
+    root: *parser.Node,
+    current_node: *parser.Node,
+    what_to_show: u32,
+    filter: ?TreeWalkerOpts,
+    filter_func: ?Env.Function,
+
+    pub const TreeWalkerOpts = union(enum) {
+        function: Env.Function,
+        object: struct { acceptNode: Env.Function },
+    };
+
+    pub fn init(node: *parser.Node, what_to_show: ?u32, filter: ?TreeWalkerOpts) !TreeWalker {
+        var filter_func: ?Env.Function = null;
+
+        if (filter) |f| {
+            filter_func = switch (f) {
+                .function => |func| func,
+                .object => |o| o.acceptNode,
+            };
+        }
+
+        return .{
+            .root = node,
+            .current_node = node,
+            .what_to_show = what_to_show orelse NodeFilter.NodeFilter._SHOW_ALL,
+            .filter = filter,
+            .filter_func = filter_func,
+        };
+    }
+
+    pub fn get_root(self: *TreeWalker) !NodeUnion {
+        return try Node.toInterface(self.root);
+    }
+
+    pub fn get_currentNode(self: *TreeWalker) !NodeUnion {
+        return try Node.toInterface(self.current_node);
+    }
+
+    pub fn get_whatToShow(self: *TreeWalker) u32 {
+        return self.what_to_show;
+    }
+
+    pub fn get_filter(self: *TreeWalker) ?TreeWalkerOpts {
+        return self.filter;
+    }
+
+    pub fn set_currentNode(self: *TreeWalker, node: *parser.Node) !void {
+        self.current_node = node;
+    }
+
+    fn firstChild(self: *const TreeWalker, node: *parser.Node) !?*parser.Node {
+        const children = try parser.nodeGetChildNodes(node);
+        const child_count = try parser.nodeListLength(children);
+
+        for (0..child_count) |i| {
+            const index: u32 = @intCast(i);
+            const child = (try parser.nodeListItem(children, index)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, child)) {
+                .accept => return child,
+                .reject => continue,
+                .skip => if (try self.firstChild(child)) |gchild| return gchild,
+            }
+        }
+
+        return null;
+    }
+
+    fn lastChild(self: *const TreeWalker, node: *parser.Node) !?*parser.Node {
+        const children = try parser.nodeGetChildNodes(node);
+        const child_count = try parser.nodeListLength(children);
+
+        var index: u32 = child_count;
+        while (index > 0) {
+            index -= 1;
+            const child = (try parser.nodeListItem(children, index)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, child)) {
+                .accept => return child,
+                .reject => continue,
+                .skip => if (try self.lastChild(child)) |gchild| return gchild,
+            }
+        }
+
+        return null;
+    }
+
+    fn nextSibling(self: *const TreeWalker, node: *parser.Node) !?*parser.Node {
+        var current = node;
+
+        while (true) {
+            current = (try parser.nodeNextSibling(current)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => return current,
+                .skip, .reject => continue,
+            }
+        }
+
+        return null;
+    }
+
+    fn previousSibling(self: *const TreeWalker, node: *parser.Node) !?*parser.Node {
+        var current = node;
+
+        while (true) {
+            current = (try parser.nodePreviousSibling(current)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => return current,
+                .skip, .reject => continue,
+            }
+        }
+
+        return null;
+    }
+
+    fn parentNode(self: *const TreeWalker, node: *parser.Node) !?*parser.Node {
+        if (self.root == node) return null;
+
+        var current = node;
+        while (true) {
+            if (current == self.root) return null;
+            current = (try parser.nodeParentNode(current)) orelse return null;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => return current,
+                .reject, .skip => continue,
+            }
+        }
+    }
+
+    pub fn _firstChild(self: *TreeWalker) !?NodeUnion {
+        if (try self.firstChild(self.current_node)) |child| {
+            self.current_node = child;
+            return try Node.toInterface(child);
+        }
+
+        return null;
+    }
+
+    pub fn _lastChild(self: *TreeWalker) !?NodeUnion {
+        if (try self.lastChild(self.current_node)) |child| {
+            self.current_node = child;
+            return try Node.toInterface(child);
+        }
+
+        return null;
+    }
+
+    pub fn _nextNode(self: *TreeWalker) !?NodeUnion {
+        if (try self.firstChild(self.current_node)) |child| {
+            self.current_node = child;
+            return try Node.toInterface(child);
+        }
+
+        var current = self.current_node;
+        while (current != self.root) {
+            if (try self.nextSibling(current)) |sibling| {
+                self.current_node = sibling;
+                return try Node.toInterface(sibling);
+            }
+
+            current = (try parser.nodeParentNode(current)) orelse break;
+        }
+
+        return null;
+    }
+
+    pub fn _nextSibling(self: *TreeWalker) !?NodeUnion {
+        if (try self.nextSibling(self.current_node)) |sibling| {
+            self.current_node = sibling;
+            return try Node.toInterface(sibling);
+        }
+
+        return null;
+    }
+
+    pub fn _parentNode(self: *TreeWalker) !?NodeUnion {
+        if (try self.parentNode(self.current_node)) |parent| {
+            self.current_node = parent;
+            return try Node.toInterface(parent);
+        }
+
+        return null;
+    }
+
+    pub fn _previousNode(self: *TreeWalker) !?NodeUnion {
+        if (self.current_node == self.root) return null;
+
+        var current = self.current_node;
+        while (try parser.nodePreviousSibling(current)) |previous| {
+            current = previous;
+
+            switch (try NodeFilter.verify(self.what_to_show, self.filter_func, current)) {
+                .accept => {
+                    // Get last child if it has one.
+                    if (try self.lastChild(current)) |child| {
+                        self.current_node = child;
+                        return try Node.toInterface(child);
+                    }
+
+                    // Otherwise, this node is our previous one.
+                    self.current_node = current;
+                    return try Node.toInterface(current);
+                },
+                .reject => continue,
+                .skip => {
+                    // Get last child if it has one.
+                    if (try self.lastChild(current)) |child| {
+                        self.current_node = child;
+                        return try Node.toInterface(child);
+                    }
+                },
+            }
+        }
+
+        if (current != self.root) {
+            if (try self.parentNode(current)) |parent| {
+                self.current_node = parent;
+                return try Node.toInterface(parent);
+            }
+        }
+
+        return null;
+    }
+
+    pub fn _previousSibling(self: *TreeWalker) !?NodeUnion {
+        if (try self.previousSibling(self.current_node)) |sibling| {
+            self.current_node = sibling;
+            return try Node.toInterface(sibling);
+        }
+
+        return null;
+    }
+};
--- a/src/browser/dom/walker.zig
+++ b/src/browser/dom/walker.zig
@@ -0,0 +1,102 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+
+pub const Walker = union(enum) {
+    walkerDepthFirst: WalkerDepthFirst,
+    walkerChildren: WalkerChildren,
+    walkerNone: WalkerNone,
+
+    pub fn get_next(self: Walker, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        switch (self) {
+            inline else => |case| return case.get_next(root, cur),
+        }
+    }
+};
+
+// WalkerDepthFirst iterates over the DOM tree to return the next following
+// node or null at the end.
+//
+// This implementation is a zig version of Netsurf code.
+// http://source.netsurf-browser.org/libdom.git/tree/src/html/html_collection.c#n177
+//
+// The iteration is a depth first as required by the specification.
+// https://dom.spec.whatwg.org/#htmlcollection
+// https://dom.spec.whatwg.org/#concept-tree-order
+pub const WalkerDepthFirst = struct {
+    pub fn get_next(_: WalkerDepthFirst, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        var n = cur orelse root;
+
+        // TODO deinit next
+        if (try parser.nodeFirstChild(n)) |next| {
+            return next;
+        }
+
+        // TODO deinit next
+        if (try parser.nodeNextSibling(n)) |next| {
+            return next;
+        }
+
+        // TODO deinit parent
+        // Back to the parent of cur.
+        // If cur has no parent, then the iteration is over.
+        var parent = try parser.nodeParentNode(n) orelse return null;
+
+        // TODO deinit lastchild
+        var lastchild = try parser.nodeLastChild(parent);
+        while (n != root and n == lastchild) {
+            n = parent;
+
+            // TODO deinit parent
+            // Back to the prev's parent.
+            // If prev has no parent, then the loop must stop.
+            parent = try parser.nodeParentNode(n) orelse break;
+
+            // TODO deinit lastchild
+            lastchild = try parser.nodeLastChild(parent);
+        }
+
+        if (n == root) {
+            return null;
+        }
+
+        return try parser.nodeNextSibling(n);
+    }
+};
+
+// WalkerChildren iterates over the root's children only.
+pub const WalkerChildren = struct {
+    pub fn get_next(_: WalkerChildren, root: *parser.Node, cur: ?*parser.Node) !?*parser.Node {
+        // On walk start, we return the first root's child.
+        if (cur == null) return try parser.nodeFirstChild(root);
+
+        // If cur is root, then return null.
+        // This is a special case, if the root is included in the walk, we
+        // don't want to go further to find children.
+        if (root == cur.?) return null;
+
+        return try parser.nodeNextSibling(cur.?);
+    }
+};
+
+pub const WalkerNone = struct {
+    pub fn get_next(_: WalkerNone, _: *parser.Node, _: ?*parser.Node) !?*parser.Node {
+        return null;
+    }
+};
--- a/src/browser/dump.zig
+++ b/src/browser/dump.zig
@@ -1,86 +1,252 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
 const std = @import("std");
-const Node = @import("webapi/Node.zig");
+
+const parser = @import("netsurf.zig");
+const Walker = @import("dom/walker.zig").WalkerChildren;

 pub const Opts = struct {
-    // @ZIGDOM (none of these do anything)
-    with_base: bool = false,
-    strip_mode: StripMode = .{},
-
-    pub const StripMode = struct {
-        js: bool = false,
-        ui: bool = false,
-        css: bool = false,
-    };
+    exclude_scripts: bool = false,
 };

-pub fn deep(node: *Node, opts: Opts, writer: *std.Io.Writer) error{WriteFailed}!void {
-    switch (node._type) {
-        .cdata => |cd| try writer.writeAll(cd.getData()),
-        .element => |el| {
-            try el.format(writer);
-            try children(node, opts, writer);
-            if (!isVoidElement(el)) {
-                try writer.writeAll("</");
-                try writer.writeAll(el.getTagNameDump());
-                try writer.writeByte('>');
+// writer must be a std.io.Writer
+pub fn writeHTML(doc: *parser.Document, opts: Opts, writer: anytype) !void {
+    try writer.writeAll("<!DOCTYPE html>\n");
+    try writeChildren(parser.documentToNode(doc), opts, writer);
+    try writer.writeAll("\n");
+}
+
+// Spec: https://www.w3.org/TR/xml/#sec-prolog-dtd
+pub fn writeDocType(doc_type: *parser.DocumentType, writer: anytype) !void {
+    try writer.writeAll("<!DOCTYPE ");
+    try writer.writeAll(try parser.documentTypeGetName(doc_type));
+
+    const public_id = try parser.documentTypeGetPublicId(doc_type);
+    const system_id = try parser.documentTypeGetSystemId(doc_type);
+    if (public_id.len != 0 and system_id.len != 0) {
+        try writer.writeAll(" PUBLIC \"");
+        try writeEscapedAttributeValue(writer, public_id);
+        try writer.writeAll("\" \"");
+        try writeEscapedAttributeValue(writer, system_id);
+        try writer.writeAll("\"");
+    } else if (public_id.len != 0) {
+        try writer.writeAll(" PUBLIC \"");
+        try writeEscapedAttributeValue(writer, public_id);
+        try writer.writeAll("\"");
+    } else if (system_id.len != 0) {
+        try writer.writeAll(" SYSTEM \"");
+        try writeEscapedAttributeValue(writer, system_id);
+        try writer.writeAll("\"");
+    }
+    // Internal subset is not implemented
+    try writer.writeAll(">");
+}
+
+pub fn writeNode(node: *parser.Node, opts: Opts, writer: anytype) anyerror!void {
+    switch (try parser.nodeType(node)) {
+        .element => {
+            // open the tag
+            const tag_type = try parser.elementHTMLGetTagType(@ptrCast(node));
+            if (tag_type == .script and opts.exclude_scripts) {
+                return;
            }
-        },
-        .document => try children(node, opts, writer),
-        .document_fragment => try children(node, opts, writer),
-        .attribute => unreachable,
-    }
-}

-pub fn children(parent: *Node, opts: Opts, writer: *std.Io.Writer) !void {
-    var it = parent.childrenIterator();
-    while (it.next()) |child| {
-        try deep(child, opts, writer);
-    }
-}
+            const tag = try parser.nodeLocalName(node);
+            try writer.writeAll("<");
+            try writer.writeAll(tag);

-pub fn toJSON(node: *Node, writer: *std.json.Stringify) !void {
-    try writer.beginObject();
-
-    try writer.objectField("type");
-    switch (node.type) {
-        .cdata => {
-            try writer.write("cdata");
-        },
-        .document => {
-            try writer.write("document");
-        },
-        .element => |*el| {
-            try writer.write("element");
-            try writer.objectField("tag");
-            try writer.write(el.tagName());
-
-            try writer.objectField("attributes");
-            try writer.beginObject();
-            var it = el.attributeIterator();
-            while (it.next()) |attr| {
-                try writer.objectField(attr.name);
-                try writer.write(attr.value);
+            // write the attributes
+            const _map = try parser.nodeGetAttributes(node);
+            if (_map) |map| {
+                const ln = try parser.namedNodeMapGetLength(map);
+                for (0..ln) |i| {
+                    const attr = try parser.namedNodeMapItem(map, @intCast(i)) orelse break;
+                    try writer.writeAll(" ");
+                    try writer.writeAll(try parser.attributeGetName(attr));
+                    try writer.writeAll("=\"");
+                    const attribute_value = try parser.attributeGetValue(attr) orelse "";
+                    try writeEscapedAttributeValue(writer, attribute_value);
+                    try writer.writeAll("\"");
+                }
            }
-            try writer.endObject();
-        },
-    }

-    try writer.objectField("children");
-    try writer.beginArray();
-    var it = node.childrenIterator();
-    while (it.next()) |child| {
-        try toJSON(child, writer);
+            try writer.writeAll(">");
+
+            // void elements can't have any content.
+            if (try isVoid(parser.nodeToElement(node))) return;
+
+            if (tag_type == .script) {
+                try writer.writeAll(try parser.nodeTextContent(node) orelse "");
+            } else {
+                // write the children
+                // TODO avoid recursion
+                try writeChildren(node, opts, writer);
+            }
+
+            // close the tag
+            try writer.writeAll("</");
+            try writer.writeAll(tag);
+            try writer.writeAll(">");
+        },
+        .text => {
+            const v = try parser.nodeValue(node) orelse return;
+            try writeEscapedTextNode(writer, v);
+        },
+        .cdata_section => {
+            const v = try parser.nodeValue(node) orelse return;
+            try writer.writeAll("<![CDATA[");
+            try writer.writeAll(v);
+            try writer.writeAll("]]>");
+        },
+        .comment => {
+            const v = try parser.nodeValue(node) orelse return;
+            try writer.writeAll("<!--");
+            try writer.writeAll(v);
+            try writer.writeAll("-->");
+        },
+        // TODO handle processing instruction dump
+        .processing_instruction => return,
+        // document fragment is outside of the main document DOM, so we
+        // don't output it.
+        .document_fragment => return,
+        // document will never be called, but required for completeness.
+        .document => return,
+        // done globally instead, but required for completeness. Only the outer DOCTYPE should be written
+        .document_type => return,
+        // deprecated
+        .attribute => return,
+        .entity_reference => return,
+        .entity => return,
+        .notation => return,
    }
-    try writer.endArray();
-    try writer.endObject();
 }

-fn isVoidElement(el: *const Node.Element) bool {
-    return switch (el._type) {
-        .html => |html| switch (html._type) {
-            .br, .hr, .img, .input, .link, .meta => true,
-            else => false,
-        },
-        .svg => false,
+// writer must be a std.io.Writer
+pub fn writeChildren(root: *parser.Node, opts: Opts, writer: anytype) !void {
+    const walker = Walker{};
+    var next: ?*parser.Node = null;
+    while (true) {
+        next = try walker.get_next(root, next) orelse break;
+        try writeNode(next.?, opts, writer);
+    }
+}
+
+// area, base, br, col, embed, hr, img, input, link, meta, source, track, wbr
+// https://html.spec.whatwg.org/#void-elements
+fn isVoid(elem: *parser.Element) !bool {
+    const tag = try parser.elementHTMLGetTagType(@as(*parser.ElementHTML, @ptrCast(elem)));
+    return switch (tag) {
+        .area, .base, .br, .col, .embed, .hr, .img, .input, .link => true,
+        .meta, .source, .track, .wbr => true,
+        else => false,
    };
 }
+
+fn writeEscapedTextNode(writer: anytype, value: []const u8) !void {
+    var v = value;
+    while (v.len > 0) {
+        const index = std.mem.indexOfAnyPos(u8, v, 0, &.{ '&', '<', '>' }) orelse {
+            return writer.writeAll(v);
+        };
+        try writer.writeAll(v[0..index]);
+        switch (v[index]) {
+            '&' => try writer.writeAll("&amp;"),
+            '<' => try writer.writeAll("&lt;"),
+            '>' => try writer.writeAll("&gt;"),
+            else => unreachable,
+        }
+        v = v[index + 1 ..];
+    }
+}
+
+fn writeEscapedAttributeValue(writer: anytype, value: []const u8) !void {
+    var v = value;
+    while (v.len > 0) {
+        const index = std.mem.indexOfAnyPos(u8, v, 0, &.{ '&', '<', '>', '"' }) orelse {
+            return writer.writeAll(v);
+        };
+        try writer.writeAll(v[0..index]);
+        switch (v[index]) {
+            '&' => try writer.writeAll("&amp;"),
+            '<' => try writer.writeAll("&lt;"),
+            '>' => try writer.writeAll("&gt;"),
+            '"' => try writer.writeAll("&quot;"),
+            else => unreachable,
+        }
+        v = v[index + 1 ..];
+    }
+}
+
+const testing = std.testing;
+test "dump.writeHTML" {
+    try parser.init();
+    defer parser.deinit();
+
+    try testWriteHTML(
+        "<div id=\"content\">Over 9000!</div>",
+        "<div id=\"content\">Over 9000!</div>",
+    );
+
+    try testWriteHTML(
+        "<root><!-- a comment --></root>",
+        "<root><!-- a comment --></root>",
+    );
+
+    try testWriteHTML(
+        "<p>&lt; &gt; &amp;</p>",
+        "<p>&lt; &gt; &amp;</p>",
+    );
+
+    try testWriteHTML(
+        "<p id=\"&quot;&gt;&lt;&amp;&quot;''\">wat?</p>",
+        "<p id='\">&lt;&amp;&quot;&#39;&apos;'>wat?</p>",
+    );
+
+    try testWriteFullHTML(
+        \\<!DOCTYPE html>
+        \\<html><head><title>It's over what?</title><meta name="a" value="b">
+        \\</head><body>9000</body></html>
+        \\
+    , "<html><title>It's over what?</title><meta name=a value=\"b\">\n<body>9000");
+
+    try testWriteHTML(
+        "<p>hi</p><script>alert(power > 9000)</script>",
+        "<p>hi</p><script>alert(power > 9000)</script>",
+    );
+}
+
+fn testWriteHTML(comptime expected_body: []const u8, src: []const u8) !void {
+    const expected =
+        "<!DOCTYPE html>\n<html><head></head><body>" ++
+        expected_body ++
+        "</body></html>\n";
+    return testWriteFullHTML(expected, src);
+}
+
+fn testWriteFullHTML(comptime expected: []const u8, src: []const u8) !void {
+    var buf = std.ArrayListUnmanaged(u8){};
+    defer buf.deinit(testing.allocator);
+
+    const doc_html = try parser.documentHTMLParseFromStr(src);
+    defer parser.documentHTMLClose(doc_html) catch {};
+
+    const doc = parser.documentHTMLToDocument(doc_html);
+    try writeHTML(doc, .{}, buf.writer(testing.allocator));
+    try testing.expectEqualStrings(expected, buf.items);
+}
--- a/src/browser/encoding/TextDecoder.zig
+++ b/src/browser/encoding/TextDecoder.zig
@@ -0,0 +1,107 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const log = @import("../../log.zig");
+
+const Env = @import("../env.zig").Env;
+
+// https://encoding.spec.whatwg.org/#interface-textdecoder
+const TextDecoder = @This();
+
+const SupportedLabels = enum {
+    utf8,
+    @"utf-8",
+    @"unicode-1-1-utf-8",
+};
+
+const Options = struct {
+    fatal: bool = false,
+    ignoreBOM: bool = false,
+};
+
+fatal: bool,
+ignore_bom: bool,
+
+pub fn constructor(label_: ?[]const u8, opts_: ?Options) !TextDecoder {
+    if (label_) |l| {
+        _ = std.meta.stringToEnum(SupportedLabels, l) orelse {
+            log.warn(.web_api, "not implemented", .{ .feature = "TextDecoder label", .label = l });
+            return error.NotImplemented;
+        };
+    }
+    const opts = opts_ orelse Options{};
+    return .{
+        .fatal = opts.fatal,
+        .ignore_bom = opts.ignoreBOM,
+    };
+}
+
+pub fn get_encoding(_: *const TextDecoder) []const u8 {
+    return "utf-8";
+}
+
+pub fn get_ignoreBOM(self: *const TextDecoder) bool {
+    return self.ignore_bom;
+}
+
+pub fn get_fatal(self: *const TextDecoder) bool {
+    return self.fatal;
+}
+
+// TODO: Should accept an ArrayBuffer, TypedArray or DataView
+// js.zig will currently only map a TypedArray to our []const u8.
+pub fn _decode(self: *const TextDecoder, v: []const u8) ![]const u8 {
+    if (self.fatal and !std.unicode.utf8ValidateSlice(v)) {
+        return error.InvalidUtf8;
+    }
+
+    if (self.ignore_bom == false and std.mem.startsWith(u8, v, &.{ 0xEF, 0xBB, 0xBF })) {
+        return v[3..];
+    }
+
+    return v;
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.Encoding.TextDecoder" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .html = "",
+    });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let d1 = new TextDecoder();", null },
+        .{ "d1.encoding;", "utf-8" },
+        .{ "d1.fatal", "false" },
+        .{ "d1.ignoreBOM", "false" },
+        .{ "d1.decode(new Uint8Array([240, 160, 174, 183]))", "𠮷" },
+        .{ "d1.decode(new Uint8Array([0xEF, 0xBB, 0xBF, 240, 160, 174, 183]))", "𠮷" },
+        .{ "d1.decode(new Uint8Array([49, 50]).buffer)", "12" },
+
+        .{ "let d2 = new TextDecoder('utf8', {fatal: true})", null },
+        .{
+            \\ try {
+            \\    let data  = new Uint8Array([240, 240, 160, 174, 183]);
+            \\    d2.decode(data);
+            \\ } catch (e) {e}
+            ,
+            "Error: InvalidUtf8",
+        },
+    }, .{});
+}
--- a/src/browser/encoding/TextEncoder.zig
+++ b/src/browser/encoding/TextEncoder.zig
@@ -0,0 +1,62 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Env = @import("../env.zig").Env;
+
+// https://encoding.spec.whatwg.org/#interface-textencoder
+const TextEncoder = @This();
+
+pub fn constructor() !TextEncoder {
+    return .{};
+}
+
+pub fn get_encoding(_: *const TextEncoder) []const u8 {
+    return "utf-8";
+}
+
+pub fn _encode(_: *const TextEncoder, v: []const u8) !Env.TypedArray(u8) {
+    // Ensure the input is a valid utf-8
+    // It seems chrome accepts invalid utf-8 sequence.
+    //
+    if (!std.unicode.utf8ValidateSlice(v)) {
+        return error.InvalidUtf8;
+    }
+
+    return .{ .values = v };
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.Encoding.TextEncoder" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{
+        .html = "",
+    });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "var encoder = new TextEncoder();", null },
+        .{ "encoder.encoding;", "utf-8" },
+        .{ "encoder.encode('€');", "226,130,172" },
+
+        // Invalid utf-8 sequence.
+        // Result with chrome:
+        // .{ "encoder.encode(new Uint8Array([0xE2,0x28,0xA1]))", "50,50,54,44,52,48,44,49,54,49" },
+        .{ "try {encoder.encode(new Uint8Array([0xE2,0x28,0xA1])) } catch (e) { e };", "Error: InvalidUtf8" },
+    }, .{});
+}
--- a/src/browser/encoding/encoding.zig
+++ b/src/browser/encoding/encoding.zig
@@ -16,24 +16,7 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.

-const js = @import("js.zig");
-const v8 = js.v8;
-
-const Platform = @This();
-inner: v8.Platform,
-
-pub fn init() !Platform {
-    if (v8.initV8ICU() == false) {
-        return error.FailedToInitializeICU;
-    }
-    const platform = v8.Platform.initDefault(0, true);
-    v8.initV8Platform(platform);
-    v8.initV8();
-    return .{ .inner = platform };
-}
-
-pub fn deinit(self: Platform) void {
-    _ = v8.deinitV8();
-    v8.deinitV8Platform();
-    self.inner.deinit();
-}
+pub const Interfaces = .{
+    @import("TextDecoder.zig"),
+    @import("TextEncoder.zig"),
+};
--- a/src/browser/env.zig
+++ b/src/browser/env.zig
@@ -0,0 +1,48 @@
+const std = @import("std");
+
+const Page = @import("page.zig").Page;
+const js = @import("../runtime/js.zig");
+const generate = @import("../runtime/generate.zig");
+
+const WebApis = struct {
+    // Wrapped like this for debug ergonomics.
+    // When we create our Env, a few lines down, we define it as:
+    //   pub const Env = js.Env(*Page, WebApis);
+    //
+    // If there's a compile time error witht he Env, it's type will be readable,
+    // i.e.: runtime.js.Env(*browser.env.Page, browser.env.WebApis)
+    //
+    // But if we didn't wrap it in the struct, like we once didn't, and defined
+    // env as:
+    //   pub const Env = js.Env(*Page, Interfaces);
+    //
+    // Because Interfaces is an anynoumous type, it doesn't have a friendly name
+    // and errors would be something like:
+    //   runtime.js.Env(*browser.Page, .{...A HUNDRED TYPES...})
+    pub const Interfaces = generate.Tuple(.{
+        @import("crypto/crypto.zig").Crypto,
+        @import("console/console.zig").Console,
+        @import("css/css.zig").Interfaces,
+        @import("cssom/cssom.zig").Interfaces,
+        @import("dom/dom.zig").Interfaces,
+        @import("dom/shadow_root.zig").ShadowRoot,
+        @import("encoding/encoding.zig").Interfaces,
+        @import("events/event.zig").Interfaces,
+        @import("html/html.zig").Interfaces,
+        @import("iterator/iterator.zig").Interfaces,
+        @import("storage/storage.zig").Interfaces,
+        @import("url/url.zig").Interfaces,
+        @import("xhr/xhr.zig").Interfaces,
+        @import("xhr/form_data.zig").Interfaces,
+        @import("xmlserializer/xmlserializer.zig").Interfaces,
+    });
+};
+
+pub const JsThis = Env.JsThis;
+pub const JsObject = Env.JsObject;
+pub const Function = Env.Function;
+pub const Promise = Env.Promise;
+pub const PromiseResolver = Env.PromiseResolver;
+
+pub const Env = js.Env(*Page, WebApis);
+pub const Global = @import("html/window.zig").Window;
--- a/src/browser/events/custom_event.zig
+++ b/src/browser/events/custom_event.zig
@@ -0,0 +1,80 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+const Event = @import("event.zig").Event;
+const JsObject = @import("../env.zig").JsObject;
+
+// https://dom.spec.whatwg.org/#interface-customevent
+pub const CustomEvent = struct {
+    pub const prototype = *Event;
+    pub const union_make_copy = true;
+
+    proto: parser.Event,
+    detail: ?JsObject,
+
+    const CustomEventInit = struct {
+        bubbles: bool = false,
+        cancelable: bool = false,
+        composed: bool = false,
+        detail: ?JsObject = null,
+    };
+
+    pub fn constructor(event_type: []const u8, opts_: ?CustomEventInit) !CustomEvent {
+        const opts = opts_ orelse CustomEventInit{};
+
+        const event = try parser.eventCreate();
+        defer parser.eventDestroy(event);
+        try parser.eventInit(event, event_type, .{
+            .bubbles = opts.bubbles,
+            .cancelable = opts.cancelable,
+            .composed = opts.composed,
+        });
+
+        return .{
+            .proto = event.*,
+            .detail = if (opts.detail) |d| try d.persist() else null,
+        };
+    }
+
+    pub fn get_detail(self: *CustomEvent) ?JsObject {
+        return self.detail;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.CustomEvent" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let capture = null", "undefined" },
+        .{ "const el = document.createElement('div');", "undefined" },
+        .{ "el.addEventListener('c1', (e) => { capture = 'c1-' + new String(e.detail)})", "undefined" },
+        .{ "el.addEventListener('c2', (e) => { capture = 'c2-' + new String(e.detail.over)})", "undefined" },
+
+        .{ "el.dispatchEvent(new CustomEvent('c1'));", "true" },
+        .{ "capture", "c1-null" },
+
+        .{ "el.dispatchEvent(new CustomEvent('c1', {detail: '123'}));", "true" },
+        .{ "capture", "c1-123" },
+
+        .{ "el.dispatchEvent(new CustomEvent('c2', {detail: {over: 9000}}));", "true" },
+        .{ "capture", "c2-9000" },
+    }, .{});
+}
--- a/src/browser/events/event.zig
+++ b/src/browser/events/event.zig
@@ -0,0 +1,449 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const generate = @import("../../runtime/generate.zig");
+
+const Page = @import("../page.zig").Page;
+const DOMException = @import("../dom/exceptions.zig").DOMException;
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+const EventTargetUnion = @import("../dom/event_target.zig").Union;
+const AbortSignal = @import("../html/AbortController.zig").AbortSignal;
+
+const CustomEvent = @import("custom_event.zig").CustomEvent;
+const ProgressEvent = @import("../xhr/progress_event.zig").ProgressEvent;
+const MouseEvent = @import("mouse_event.zig").MouseEvent;
+const ErrorEvent = @import("../html/error_event.zig").ErrorEvent;
+const MessageEvent = @import("../dom/MessageChannel.zig").MessageEvent;
+
+// Event interfaces
+pub const Interfaces = .{ Event, CustomEvent, ProgressEvent, MouseEvent, ErrorEvent, MessageEvent };
+
+pub const Union = generate.Union(Interfaces);
+
+// https://dom.spec.whatwg.org/#event
+pub const Event = struct {
+    pub const Self = parser.Event;
+    pub const Exception = DOMException;
+
+    pub const EventInit = parser.EventInit;
+
+    // JS
+    // --
+
+    pub const _CAPTURING_PHASE = 1;
+    pub const _AT_TARGET = 2;
+    pub const _BUBBLING_PHASE = 3;
+
+    pub fn toInterface(evt: *parser.Event) !Union {
+        return switch (try parser.eventGetInternalType(evt)) {
+            .event, .abort_signal, .xhr_event => .{ .Event = evt },
+            .custom_event => .{ .CustomEvent = @as(*CustomEvent, @ptrCast(evt)).* },
+            .progress_event => .{ .ProgressEvent = @as(*ProgressEvent, @ptrCast(evt)).* },
+            .mouse_event => .{ .MouseEvent = @as(*parser.MouseEvent, @ptrCast(evt)) },
+            .error_event => .{ .ErrorEvent = @as(*ErrorEvent, @ptrCast(evt)).* },
+            .message_event => .{ .MessageEvent = @as(*MessageEvent, @ptrCast(evt)).* },
+        };
+    }
+
+    pub fn constructor(event_type: []const u8, opts: ?EventInit) !*parser.Event {
+        const event = try parser.eventCreate();
+        try parser.eventInit(event, event_type, opts orelse EventInit{});
+        return event;
+    }
+
+    // Getters
+
+    pub fn get_type(self: *parser.Event) ![]const u8 {
+        return try parser.eventType(self);
+    }
+
+    pub fn get_target(self: *parser.Event, page: *Page) !?EventTargetUnion {
+        const et = try parser.eventTarget(self);
+        if (et == null) return null;
+        return try EventTarget.toInterface(et.?, page);
+    }
+
+    pub fn get_currentTarget(self: *parser.Event, page: *Page) !?EventTargetUnion {
+        const et = try parser.eventCurrentTarget(self);
+        if (et == null) return null;
+        return try EventTarget.toInterface(et.?, page);
+    }
+
+    pub fn get_eventPhase(self: *parser.Event) !u8 {
+        return try parser.eventPhase(self);
+    }
+
+    pub fn get_bubbles(self: *parser.Event) !bool {
+        return try parser.eventBubbles(self);
+    }
+
+    pub fn get_cancelable(self: *parser.Event) !bool {
+        return try parser.eventCancelable(self);
+    }
+
+    pub fn get_defaultPrevented(self: *parser.Event) !bool {
+        return try parser.eventDefaultPrevented(self);
+    }
+
+    pub fn get_isTrusted(self: *parser.Event) !bool {
+        return try parser.eventIsTrusted(self);
+    }
+
+    pub fn get_timestamp(self: *parser.Event) !u32 {
+        return try parser.eventTimestamp(self);
+    }
+
+    // Methods
+
+    pub fn _initEvent(
+        self: *parser.Event,
+        eventType: []const u8,
+        bubbles: ?bool,
+        cancelable: ?bool,
+    ) !void {
+        const opts = EventInit{
+            .bubbles = bubbles orelse false,
+            .cancelable = cancelable orelse false,
+        };
+        return try parser.eventInit(self, eventType, opts);
+    }
+
+    pub fn _stopPropagation(self: *parser.Event) !void {
+        return try parser.eventStopPropagation(self);
+    }
+
+    pub fn _stopImmediatePropagation(self: *parser.Event) !void {
+        return try parser.eventStopImmediatePropagation(self);
+    }
+
+    pub fn _preventDefault(self: *parser.Event) !void {
+        return try parser.eventPreventDefault(self);
+    }
+};
+
+pub const EventHandler = struct {
+    once: bool,
+    capture: bool,
+    callback: Function,
+    node: parser.EventNode,
+    listener: *parser.EventListener,
+
+    const Env = @import("../env.zig").Env;
+    const Function = Env.Function;
+
+    pub const Listener = union(enum) {
+        function: Function,
+        object: Env.JsObject,
+
+        pub fn callback(self: Listener, target: *parser.EventTarget) !?Function {
+            return switch (self) {
+                .function => |func| try func.withThis(target),
+                .object => |obj| blk: {
+                    const func = (try obj.getFunction("handleEvent")) orelse return null;
+                    break :blk try func.withThis(try obj.persist());
+                },
+            };
+        }
+    };
+
+    pub const Opts = union(enum) {
+        flags: Flags,
+        capture: bool,
+
+        const Flags = struct {
+            once: ?bool,
+            capture: ?bool,
+            // We ignore this property. It seems to be largely used to help the
+            // browser make certain performance tweaks (i.e. the browser knows
+            // that the listener won't call preventDefault() and thus can safely
+            // run the default as needed).
+            passive: ?bool,
+            signal: ?*AbortSignal, // currently does nothing
+        };
+    };
+
+    pub fn register(
+        allocator: Allocator,
+        target: *parser.EventTarget,
+        typ: []const u8,
+        listener: Listener,
+        opts_: ?Opts,
+    ) !?*EventHandler {
+        var once = false;
+        var capture = false;
+        var signal: ?*AbortSignal = null;
+
+        if (opts_) |opts| {
+            switch (opts) {
+                .capture => |c| capture = c,
+                .flags => |f| {
+                    once = f.once orelse false;
+                    signal = f.signal orelse null;
+                    capture = f.capture orelse false;
+                },
+            }
+        }
+
+        const callback = (try listener.callback(target)) orelse return null;
+
+        if (signal) |s| {
+            const signal_target = parser.toEventTarget(AbortSignal, s);
+
+            const scb = try allocator.create(SignalCallback);
+            scb.* = .{
+                .target = target,
+                .capture = capture,
+                .callback_id = callback.id,
+                .typ = try allocator.dupe(u8, typ),
+                .signal_target = signal_target,
+                .signal_listener = undefined,
+                .node = .{ .func = SignalCallback.handle },
+            };
+
+            scb.signal_listener = try parser.eventTargetAddEventListener(
+                signal_target,
+                "abort",
+                &scb.node,
+                false,
+            );
+        }
+
+        // check if event target has already this listener
+        if (try parser.eventTargetHasListener(target, typ, capture, callback.id) != null) {
+            return null;
+        }
+
+        const eh = try allocator.create(EventHandler);
+        eh.* = .{
+            .once = once,
+            .capture = capture,
+            .callback = callback,
+            .node = .{
+                .id = callback.id,
+                .func = handle,
+            },
+            .listener = undefined,
+        };
+
+        eh.listener = try parser.eventTargetAddEventListener(
+            target,
+            typ,
+            &eh.node,
+            capture,
+        );
+        return eh;
+    }
+
+    fn handle(node: *parser.EventNode, event: *parser.Event) void {
+        const ievent = Event.toInterface(event) catch |err| {
+            log.err(.app, "toInterface error", .{ .err = err });
+            return;
+        };
+
+        const self: *EventHandler = @fieldParentPtr("node", node);
+        var result: Function.Result = undefined;
+        self.callback.tryCall(void, .{ievent}, &result) catch {
+            log.debug(.user_script, "callback error", .{
+                .err = result.exception,
+                .stack = result.stack,
+                .source = "event handler",
+            });
+        };
+
+        if (self.once) {
+            const target = (parser.eventTarget(event) catch return).?;
+            const typ = parser.eventType(event) catch return;
+            parser.eventTargetRemoveEventListener(
+                target,
+                typ,
+                self.listener,
+                self.capture,
+            ) catch {};
+        }
+    }
+};
+
+const SignalCallback = struct {
+    typ: []const u8,
+    capture: bool,
+    callback_id: usize,
+    node: parser.EventNode,
+    target: *parser.EventTarget,
+    signal_target: *parser.EventTarget,
+    signal_listener: *parser.EventListener,
+
+    fn handle(node: *parser.EventNode, _: *parser.Event) void {
+        const self: *SignalCallback = @fieldParentPtr("node", node);
+        self._handle() catch |err| {
+            log.err(.app, "event signal handler", .{ .err = err });
+        };
+    }
+
+    fn _handle(self: *SignalCallback) !void {
+        const lst = try parser.eventTargetHasListener(
+            self.target,
+            self.typ,
+            self.capture,
+            self.callback_id,
+        );
+        if (lst == null) {
+            return;
+        }
+
+        try parser.eventTargetRemoveEventListener(
+            self.target,
+            self.typ,
+            lst.?,
+            self.capture,
+        );
+
+        // remove the abort signal listener itself
+        try parser.eventTargetRemoveEventListener(
+            self.signal_target,
+            "abort",
+            self.signal_listener,
+            false,
+        );
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.Event" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let content = document.getElementById('content')", "undefined" },
+        .{ "let para = document.getElementById('para')", "undefined" },
+        .{ "var nb = 0; var evt", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ content.addEventListener('target', function(e) {
+            \\  evt = e; nb = nb + 1;
+            \\  e.preventDefault();
+            \\ })
+            ,
+            "undefined",
+        },
+        .{ "content.dispatchEvent(new Event('target', {bubbles: true, cancelable: true}))", "false" },
+        .{ "nb", "1" },
+        .{ "evt.target === content", "true" },
+        .{ "evt.bubbles", "true" },
+        .{ "evt.cancelable", "true" },
+        .{ "evt.defaultPrevented", "true" },
+        .{ "evt.isTrusted", "true" },
+        .{ "evt.timestamp > 1704063600", "true" }, // 2024/01/01 00:00
+        // event.type, event.currentTarget, event.phase checked in EventTarget
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0", "0" },
+        .{
+            \\ content.addEventListener('stop',function(e) {
+            \\    e.stopPropagation();
+            \\    nb = nb + 1;
+            \\  }, true)
+            ,
+            "undefined",
+        },
+        // the following event listener will not be invoked
+        .{
+            \\  para.addEventListener('stop',function(e) {
+            \\    nb = nb + 1;
+            \\  })
+            ,
+            "undefined",
+        },
+        .{ "para.dispatchEvent(new Event('stop'))", "true" },
+        .{ "nb", "1" }, // will be 2 if event was not stopped at content event listener
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0", "0" },
+        .{
+            \\  content.addEventListener('immediate', function(e) {
+            \\    e.stopImmediatePropagation();
+            \\    nb = nb + 1;
+            \\  })
+            ,
+            "undefined",
+        },
+        // the following event listener will not be invoked
+        .{
+            \\  content.addEventListener('immediate', function(e) {
+            \\    nb = nb + 1;
+            \\  })
+            ,
+            "undefined",
+        },
+        .{ "content.dispatchEvent(new Event('immediate'))", "true" },
+        .{ "nb", "1" }, // will be 2 if event was not stopped at first content event listener
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0", "0" },
+        .{
+            \\  content.addEventListener('legacy', function(e) {
+            \\     evt = e; nb = nb + 1;
+            \\  })
+            ,
+            "undefined",
+        },
+        .{ "let evtLegacy = document.createEvent('Event')", "undefined" },
+        .{ "evtLegacy.initEvent('legacy')", "undefined" },
+        .{ "content.dispatchEvent(evtLegacy)", "true" },
+        .{ "nb", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var nb = 0; var evt = null; function cbk(event) { nb ++; evt=event; }", "undefined" },
+        .{ "document.addEventListener('count', cbk)", "undefined" },
+        .{ "document.removeEventListener('count', cbk)", "undefined" },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "nb", "0" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; function cbk(event) { nb ++; }", null },
+        .{ "document.addEventListener('count', cbk, {once: true})", null },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "nb", "1" },
+        .{ "document.removeEventListener('count', cbk)", "undefined" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "nb = 0; function cbk(event) { nb ++; }", null },
+        .{ "let ac = new AbortController()", null },
+        .{ "document.addEventListener('count', cbk, {signal: ac.signal})", null },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "ac.abort()", null },
+        .{ "document.dispatchEvent(new Event('count'))", "true" },
+        .{ "nb", "2" },
+        .{ "document.removeEventListener('count', cbk)", "undefined" },
+    }, .{});
+}
--- a/src/browser/events/mouse_event.zig
+++ b/src/browser/events/mouse_event.zig
@@ -0,0 +1,140 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const log = std.log.scoped(.mouse_event);
+
+const parser = @import("../netsurf.zig");
+const Event = @import("event.zig").Event;
+const JsObject = @import("../env.zig").JsObject;
+
+// TODO: We currently don't have a UIEvent interface so we skip it in the prototype chain.
+// https://developer.mozilla.org/en-US/docs/Web/API/UIEvent
+const UIEvent = Event;
+
+// https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent
+pub const MouseEvent = struct {
+    pub const Self = parser.MouseEvent;
+    pub const prototype = *UIEvent;
+
+    const MouseButton = enum(u16) {
+        main_button = 0,
+        auxillary_button = 1,
+        secondary_button = 2,
+        fourth_button = 3,
+        fifth_button = 4,
+    };
+
+    const MouseEventInit = struct {
+        screenX: i32 = 0,
+        screenY: i32 = 0,
+        clientX: i32 = 0,
+        clientY: i32 = 0,
+        ctrlKey: bool = false,
+        shiftKey: bool = false,
+        altKey: bool = false,
+        metaKey: bool = false,
+        button: MouseButton = .main_button,
+    };
+
+    pub fn constructor(event_type: []const u8, opts_: ?MouseEventInit) !*parser.MouseEvent {
+        const opts = opts_ orelse MouseEventInit{};
+
+        var mouse_event = try parser.mouseEventCreate();
+        try parser.eventSetInternalType(@ptrCast(&mouse_event), .mouse_event);
+
+        try parser.mouseEventInit(mouse_event, event_type, .{
+            .x = opts.clientX,
+            .y = opts.clientY,
+            .ctrl = opts.ctrlKey,
+            .shift = opts.shiftKey,
+            .alt = opts.altKey,
+            .meta = opts.metaKey,
+            .button = @intFromEnum(opts.button),
+        });
+
+        if (!std.mem.eql(u8, event_type, "click")) {
+            log.warn("MouseEvent currently only supports listeners for 'click' events!", .{});
+        }
+
+        return mouse_event;
+    }
+
+    pub fn get_button(self: *parser.MouseEvent) u16 {
+        return self.button;
+    }
+
+    // These is just an alias for clientX.
+    pub fn get_x(self: *parser.MouseEvent) i32 {
+        return self.cx;
+    }
+
+    // These is just an alias for clientY.
+    pub fn get_y(self: *parser.MouseEvent) i32 {
+        return self.cy;
+    }
+
+    pub fn get_clientX(self: *parser.MouseEvent) i32 {
+        return self.cx;
+    }
+
+    pub fn get_clientY(self: *parser.MouseEvent) i32 {
+        return self.cy;
+    }
+
+    pub fn get_screenX(self: *parser.MouseEvent) i32 {
+        return self.sx;
+    }
+
+    pub fn get_screenY(self: *parser.MouseEvent) i32 {
+        return self.sy;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.MouseEvent" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        // Default MouseEvent
+        .{ "let event = new MouseEvent('click')", "undefined" },
+        .{ "event.type", "click" },
+        .{ "event instanceof MouseEvent", "true" },
+        .{ "event instanceof Event", "true" },
+        .{ "event.clientX", "0" },
+        .{ "event.clientY", "0" },
+        .{ "event.screenX", "0" },
+        .{ "event.screenY", "0" },
+        // MouseEvent with parameters
+        .{ "let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20 })", "undefined" },
+        .{ "new_event.button", "0" },
+        .{ "new_event.x", "10" },
+        .{ "new_event.y", "20" },
+        .{ "new_event.screenX", "10" },
+        .{ "new_event.screenY", "20" },
+        // MouseEvent Listener
+        .{ "let me = new MouseEvent('click')", "undefined" },
+        .{ "me instanceof Event", "true" },
+        .{ "var eevt = null; function ccbk(event) { eevt = event; }", "undefined" },
+        .{ "document.addEventListener('click', ccbk)", "undefined" },
+        .{ "document.dispatchEvent(me)", "true" },
+        .{ "eevt.type", "click" },
+        .{ "eevt instanceof MouseEvent", "true" },
+    }, .{});
+}
--- a/src/browser/html/AbortController.zig
+++ b/src/browser/html/AbortController.zig
@@ -0,0 +1,187 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const Env = @import("../env.zig").Env;
+const Page = @import("../page.zig").Page;
+const Loop = @import("../../runtime/loop.zig").Loop;
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+
+pub const Interfaces = .{
+    AbortController,
+    AbortSignal,
+};
+
+const AbortController = @This();
+
+signal: *AbortSignal,
+
+pub fn constructor(page: *Page) !AbortController {
+    // Why do we allocate this rather than storing directly in the struct?
+    // https://github.com/lightpanda-io/project/discussions/165
+    const signal = try page.arena.create(AbortSignal);
+    signal.* = .init;
+
+    return .{
+        .signal = signal,
+    };
+}
+
+pub fn get_signal(self: *AbortController) *AbortSignal {
+    return self.signal;
+}
+
+pub fn _abort(self: *AbortController, reason_: ?[]const u8) !void {
+    return self.signal.abort(reason_);
+}
+
+pub const AbortSignal = struct {
+    const DEFAULT_REASON = "AbortError";
+
+    pub const prototype = *EventTarget;
+    proto: parser.EventTargetTBase = .{ .internal_target_type = .abort_signal },
+
+    aborted: bool,
+    reason: ?[]const u8,
+
+    pub const init: AbortSignal = .{
+        .reason = null,
+        .aborted = false,
+    };
+
+    pub fn static_abort(reason_: ?[]const u8) AbortSignal {
+        return .{
+            .aborted = true,
+            .reason = reason_ orelse DEFAULT_REASON,
+        };
+    }
+
+    pub fn static_timeout(delay: u32, page: *Page) !*AbortSignal {
+        const callback = try page.arena.create(TimeoutCallback);
+        callback.* = .{
+            .signal = .init,
+            .node = .{ .func = TimeoutCallback.run },
+        };
+
+        const delay_ms: u63 = @as(u63, delay) * std.time.ns_per_ms;
+        _ = try page.loop.timeout(delay_ms, &callback.node);
+        return &callback.signal;
+    }
+
+    pub fn get_aborted(self: *const AbortSignal) bool {
+        return self.aborted;
+    }
+
+    fn abort(self: *AbortSignal, reason_: ?[]const u8) !void {
+        self.aborted = true;
+        self.reason = reason_ orelse DEFAULT_REASON;
+
+        const abort_event = try parser.eventCreate();
+        try parser.eventSetInternalType(abort_event, .abort_signal);
+
+        defer parser.eventDestroy(abort_event);
+        try parser.eventInit(abort_event, "abort", .{});
+        _ = try parser.eventTargetDispatchEvent(
+            parser.toEventTarget(AbortSignal, self),
+            abort_event,
+        );
+    }
+
+    const Reason = union(enum) {
+        reason: []const u8,
+        undefined: void,
+    };
+    pub fn get_reason(self: *const AbortSignal) Reason {
+        if (self.reason) |r| {
+            return .{ .reason = r };
+        }
+        return .{ .undefined = {} };
+    }
+
+    const ThrowIfAborted = union(enum) {
+        exception: Env.Exception,
+        undefined: void,
+    };
+    pub fn _throwIfAborted(self: *const AbortSignal, page: *Page) ThrowIfAborted {
+        if (self.aborted) {
+            const ex = page.main_context.throw(self.reason orelse DEFAULT_REASON);
+            return .{ .exception = ex };
+        }
+        return .{ .undefined = {} };
+    }
+};
+
+const TimeoutCallback = struct {
+    signal: AbortSignal,
+
+    // This is the internal data that the event loop tracks. We'll get this
+    // back in run and, from it, can get our TimeoutCallback instance
+    node: Loop.CallbackNode = undefined,
+
+    fn run(node: *Loop.CallbackNode, _: *?u63) void {
+        const self: *TimeoutCallback = @fieldParentPtr("node", node);
+        self.signal.abort("TimeoutError") catch |err| {
+            log.warn(.app, "abort signal timeout", .{ .err = err });
+        };
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.AbortController" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "var called = 0", null },
+        .{ "var a1 = new AbortController()", null },
+        .{ "var s1 = a1.signal", null },
+        .{ "s1.throwIfAborted()", "undefined" },
+        .{ "s1.reason", "undefined" },
+        .{ "var target;", null },
+        .{
+            \\ s1.addEventListener('abort', (e) => {
+            \\   called += 1;
+            \\   target = e.target;
+            \\
+            \\ });
+            ,
+            null,
+        },
+        .{ "a1.abort()", null },
+        .{ "s1.aborted", "true" },
+        .{ "target == s1", "true" },
+        .{ "s1.reason", "AbortError" },
+        .{ "called", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var s2 = AbortSignal.abort('over 9000')", null },
+        .{ "s2.aborted", "true" },
+        .{ "s2.reason", "over 9000" },
+        .{ "AbortSignal.abort().reason", "AbortError" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "var s3 = AbortSignal.timeout(10)", null },
+        .{ "s3.aborted", "true" },
+        .{ "s3.reason", "TimeoutError" },
+        .{ "try { s3.throwIfAborted() } catch (e) { e }", "Error: TimeoutError" },
+    }, .{});
+}
--- a/src/browser/html/DataSet.zig
+++ b/src/browser/html/DataSet.zig
@@ -0,0 +1,97 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+const std = @import("std");
+const parser = @import("../netsurf.zig");
+const Env = @import("../env.zig").Env;
+const Page = @import("../page.zig").Page;
+
+const Allocator = std.mem.Allocator;
+
+const DataSet = @This();
+
+element: *parser.Element,
+
+pub fn named_get(self: *const DataSet, name: []const u8, _: *bool, page: *Page) !Env.UndefinedOr([]const u8) {
+    const normalized_name = try normalize(page.call_arena, name);
+    if (try parser.elementGetAttribute(self.element, normalized_name)) |value| {
+        return .{ .value = value };
+    }
+    return .undefined;
+}
+
+pub fn named_set(self: *DataSet, name: []const u8, value: []const u8, _: *bool, page: *Page) !void {
+    const normalized_name = try normalize(page.call_arena, name);
+    try parser.elementSetAttribute(self.element, normalized_name, value);
+}
+
+pub fn named_delete(self: *DataSet, name: []const u8, _: *bool, page: *Page) !void {
+    const normalized_name = try normalize(page.call_arena, name);
+    try parser.elementRemoveAttribute(self.element, normalized_name);
+}
+
+fn normalize(allocator: Allocator, name: []const u8) ![]const u8 {
+    var upper_count: usize = 0;
+    for (name) |c| {
+        if (std.ascii.isUpper(c)) {
+            upper_count += 1;
+        }
+    }
+    // for every upper-case letter, we'll probably need a dash before it
+    // and we need the 'data-' prefix
+    var normalized = try allocator.alloc(u8, name.len + upper_count + 5);
+
+    @memcpy(normalized[0..5], "data-");
+    if (upper_count == 0) {
+        @memcpy(normalized[5..], name);
+        return normalized;
+    }
+
+    var pos: usize = 5;
+    for (name) |c| {
+        if (std.ascii.isUpper(c)) {
+            normalized[pos] = '-';
+            pos += 1;
+            normalized[pos] = c + 32;
+        } else {
+            normalized[pos] = c;
+        }
+        pos += 1;
+    }
+    return normalized;
+}
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.DataSet" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{ .html = "" });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let el1 = document.createElement('div')", null },
+        .{ "el1.dataset.x", "undefined" },
+        .{ "el1.dataset.x = '123'", "123" },
+        .{ "delete el1.dataset.x", "true" },
+        .{ "el1.dataset.x", "undefined" },
+        .{ "delete el1.dataset.other", "true" }, // yes, this is right
+
+        .{ "let ds1 = el1.dataset", null },
+        .{ "ds1.helloWorld = 'yes'", null },
+        .{ "el1.getAttribute('data-hello-world')", "yes" },
+        .{ "el1.setAttribute('data-this-will-work', 'positive')", null },
+        .{ "ds1.thisWillWork", "positive" },
+    }, .{});
+}
--- a/src/browser/html/document.zig
+++ b/src/browser/html/document.zig
@@ -0,0 +1,412 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const log = @import("../../log.zig");
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+
+const Window = @import("window.zig").Window;
+const Element = @import("../dom/element.zig").Element;
+const ElementUnion = @import("../dom/element.zig").Union;
+const Document = @import("../dom/document.zig").Document;
+const NodeList = @import("../dom/nodelist.zig").NodeList;
+const Location = @import("location.zig").Location;
+
+const collection = @import("../dom/html_collection.zig");
+const Walker = @import("../dom/walker.zig").WalkerDepthFirst;
+const Cookie = @import("../storage/cookie.zig").Cookie;
+
+// WEB IDL https://html.spec.whatwg.org/#the-document-object
+pub const HTMLDocument = struct {
+    pub const Self = parser.DocumentHTML;
+    pub const prototype = *Document;
+    pub const subtype = .node;
+
+    // JS funcs
+    // --------
+
+    pub fn get_domain(self: *parser.DocumentHTML, page: *Page) ![]const u8 {
+        // libdom's document_html get_domain always returns null, this is
+        // the way MDN recommends getting the domain anyways, since document.domain
+        // is deprecated.
+        const location = try parser.documentHTMLGetLocation(Location, self) orelse return "";
+        return location.get_host(page);
+    }
+
+    pub fn set_domain(_: *parser.DocumentHTML, _: []const u8) ![]const u8 {
+        return error.NotImplemented;
+    }
+
+    pub fn get_referrer(self: *parser.DocumentHTML) ![]const u8 {
+        return try parser.documentHTMLGetReferrer(self);
+    }
+
+    pub fn set_referrer(_: *parser.DocumentHTML, _: []const u8) ![]const u8 {
+        return error.NotImplemented;
+    }
+
+    pub fn get_body(self: *parser.DocumentHTML) !?*parser.Body {
+        return try parser.documentHTMLBody(self);
+    }
+
+    pub fn set_body(self: *parser.DocumentHTML, elt: ?*parser.ElementHTML) !?*parser.Body {
+        try parser.documentHTMLSetBody(self, elt);
+        return try get_body(self);
+    }
+
+    pub fn get_head(self: *parser.DocumentHTML) !?*parser.Head {
+        const root = parser.documentHTMLToNode(self);
+        const walker = Walker{};
+        var next: ?*parser.Node = null;
+        while (true) {
+            next = try walker.get_next(root, next) orelse return null;
+            if (std.ascii.eqlIgnoreCase("head", try parser.nodeName(next.?))) {
+                return @as(*parser.Head, @ptrCast(next.?));
+            }
+        }
+    }
+
+    pub fn get_cookie(_: *parser.DocumentHTML, page: *Page) ![]const u8 {
+        var buf: std.ArrayListUnmanaged(u8) = .{};
+        try page.cookie_jar.forRequest(&page.url.uri, buf.writer(page.arena), .{ .navigation = true, .is_http = false });
+        return buf.items;
+    }
+
+    pub fn set_cookie(_: *parser.DocumentHTML, cookie_str: []const u8, page: *Page) ![]const u8 {
+        // we use the cookie jar's allocator to parse the cookie because it
+        // outlives the page's arena.
+        const c = try Cookie.parse(page.cookie_jar.allocator, &page.url.uri, cookie_str);
+        errdefer c.deinit();
+        if (c.http_only) {
+            c.deinit();
+            return ""; // HttpOnly cookies cannot be set from JS
+        }
+        try page.cookie_jar.add(c, std.time.timestamp());
+        return cookie_str;
+    }
+
+    pub fn get_title(self: *parser.DocumentHTML) ![]const u8 {
+        return try parser.documentHTMLGetTitle(self);
+    }
+
+    pub fn set_title(self: *parser.DocumentHTML, v: []const u8) ![]const u8 {
+        try parser.documentHTMLSetTitle(self, v);
+        return v;
+    }
+
+    pub fn _getElementsByName(self: *parser.DocumentHTML, name: []const u8, page: *Page) !NodeList {
+        const arena = page.arena;
+        var list: NodeList = .{};
+
+        if (name.len == 0) return list;
+
+        const root = parser.documentHTMLToNode(self);
+        var c = try collection.HTMLCollectionByName(arena, root, name, false);
+
+        const ln = try c.get_length();
+        var i: u32 = 0;
+        while (i < ln) {
+            const n = try c.item(i) orelse break;
+            try list.append(arena, n);
+            i += 1;
+        }
+
+        return list;
+    }
+
+    pub fn get_images(self: *parser.DocumentHTML, page: *Page) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(page.arena, parser.documentHTMLToNode(self), "img", false);
+    }
+
+    pub fn get_embeds(self: *parser.DocumentHTML, page: *Page) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(page.arena, parser.documentHTMLToNode(self), "embed", false);
+    }
+
+    pub fn get_plugins(self: *parser.DocumentHTML, page: *Page) !collection.HTMLCollection {
+        return get_embeds(self, page);
+    }
+
+    pub fn get_forms(self: *parser.DocumentHTML, page: *Page) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(page.arena, parser.documentHTMLToNode(self), "form", false);
+    }
+
+    pub fn get_scripts(self: *parser.DocumentHTML, page: *Page) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByTagName(page.arena, parser.documentHTMLToNode(self), "script", false);
+    }
+
+    pub fn get_applets(_: *parser.DocumentHTML) !collection.HTMLCollection {
+        return try collection.HTMLCollectionEmpty();
+    }
+
+    pub fn get_links(self: *parser.DocumentHTML) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByLinks(parser.documentHTMLToNode(self), false);
+    }
+
+    pub fn get_anchors(self: *parser.DocumentHTML) !collection.HTMLCollection {
+        return try collection.HTMLCollectionByAnchors(parser.documentHTMLToNode(self), false);
+    }
+
+    pub fn get_all(self: *parser.DocumentHTML) collection.HTMLAllCollection {
+        return collection.HTMLAllCollection.init(parser.documentHTMLToNode(self));
+    }
+
+    pub fn get_currentScript(self: *parser.DocumentHTML) !?*parser.Script {
+        return try parser.documentHTMLGetCurrentScript(self);
+    }
+
+    pub fn get_location(self: *parser.DocumentHTML) !?*Location {
+        return try parser.documentHTMLGetLocation(Location, self);
+    }
+
+    pub fn set_location(_: *const parser.DocumentHTML, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url, .{ .reason = .script });
+    }
+
+    pub fn get_designMode(_: *parser.DocumentHTML) []const u8 {
+        return "off";
+    }
+
+    pub fn set_designMode(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "off";
+    }
+
+    pub fn get_defaultView(_: *parser.DocumentHTML, page: *Page) *Window {
+        return &page.window;
+    }
+
+    pub fn get_readyState(self: *parser.DocumentHTML, page: *Page) ![]const u8 {
+        const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
+        return @tagName(state.ready_state);
+    }
+
+    // noop legacy functions
+    // https://html.spec.whatwg.org/#Document-partial
+    pub fn _clear(_: *parser.DocumentHTML) void {}
+    pub fn _captureEvents(_: *parser.DocumentHTML) void {}
+    pub fn _releaseEvents(_: *parser.DocumentHTML) void {}
+
+    pub fn get_fgColor(_: *parser.DocumentHTML) []const u8 {
+        return "";
+    }
+    pub fn set_fgColor(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "";
+    }
+    pub fn get_linkColor(_: *parser.DocumentHTML) []const u8 {
+        return "";
+    }
+    pub fn set_linkColor(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "";
+    }
+    pub fn get_vlinkColor(_: *parser.DocumentHTML) []const u8 {
+        return "";
+    }
+    pub fn set_vlinkColor(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "";
+    }
+    pub fn get_alinkColor(_: *parser.DocumentHTML) []const u8 {
+        return "";
+    }
+    pub fn set_alinkColor(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "";
+    }
+    pub fn get_bgColor(_: *parser.DocumentHTML) []const u8 {
+        return "";
+    }
+    pub fn set_bgColor(_: *parser.DocumentHTML, _: []const u8) []const u8 {
+        return "";
+    }
+
+    // Returns the topmost Element at the specified coordinates (relative to the viewport).
+    // Since LightPanda requires the client to know what they are clicking on we do not return the underlying element at this moment
+    // This can currenty only happen if the first pixel is clicked without having rendered any element. This will change when css properties are supported.
+    // This returns an ElementUnion instead of a *Parser.Element in case the element somehow hasn't passed through the js runtime yet.
+    // While x and y should be f32, here we take i32 since that's what our
+    // "renderer" uses. By specifying i32 here, rather than f32 and doing the
+    // conversion ourself, we rely on v8's type conversion which is both more
+    // flexible (e.g. handles NaN) and will be more consistent with a browser.
+    pub fn _elementFromPoint(_: *parser.DocumentHTML, x: i32, y: i32, page: *Page) !?ElementUnion {
+        const element = page.renderer.getElementAtPosition(x, y) orelse return null;
+        // TODO if pointer-events set to none the underlying element should be returned (parser.documentGetDocumentElement(self.document);?)
+        return try Element.toInterface(element);
+    }
+
+    // Returns an array of all elements at the specified coordinates (relative to the viewport). The elements are ordered from the topmost to the bottommost box of the viewport.
+    // While x and y should be f32, here we take i32 since that's what our
+    // "renderer" uses. By specifying i32 here, rather than f32 and doing the
+    // conversion ourself, we rely on v8's type conversion which is both more
+    // flexible (e.g. handles NaN) and will be more consistent with a browser.
+    pub fn _elementsFromPoint(_: *parser.DocumentHTML, x: i32, y: i32, page: *Page) ![]ElementUnion {
+        const element = page.renderer.getElementAtPosition(x, y) orelse return &.{};
+        // TODO if pointer-events set to none the underlying element should be returned (parser.documentGetDocumentElement(self.document);?)
+
+        var list: std.ArrayListUnmanaged(ElementUnion) = .empty;
+        try list.ensureTotalCapacity(page.call_arena, 3);
+        list.appendAssumeCapacity(try Element.toInterface(element));
+
+        // Since we are using a flat renderer there is no hierarchy of elements. What we do know is that the element is part of the main document.
+        // Thus we can add the HtmlHtmlElement and it's child HTMLBodyElement to the returned list.
+        // TBD Should we instead return every parent that is an element? Note that a child does not physically need to be overlapping the parent.
+        // Should we do a render pass on demand?
+        const doc_elem = try parser.documentGetDocumentElement(parser.documentHTMLToDocument(page.window.document)) orelse {
+            return list.items;
+        };
+        if (try parser.documentHTMLBody(page.window.document)) |body| {
+            list.appendAssumeCapacity(try Element.toInterface(parser.bodyToElement(body)));
+        }
+        list.appendAssumeCapacity(try Element.toInterface(doc_elem));
+        return list.items;
+    }
+
+    pub fn documentIsLoaded(self: *parser.DocumentHTML, page: *Page) !void {
+        const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
+        state.ready_state = .interactive;
+
+        log.debug(.script_event, "dispatch event", .{
+            .type = "DOMContentLoaded",
+            .source = "document",
+        });
+
+        const evt = try parser.eventCreate();
+        defer parser.eventDestroy(evt);
+        try parser.eventInit(evt, "DOMContentLoaded", .{ .bubbles = true, .cancelable = true });
+        _ = try parser.eventTargetDispatchEvent(parser.toEventTarget(parser.DocumentHTML, self), evt);
+
+        try page.window.dispatchForDocumentTarget(evt);
+    }
+
+    pub fn documentIsComplete(self: *parser.DocumentHTML, page: *Page) !void {
+        const state = try page.getOrCreateNodeState(@alignCast(@ptrCast(self)));
+        state.ready_state = .complete;
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+
+test "Browser.HTML.Document" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "document.__proto__.constructor.name", "HTMLDocument" },
+        .{ "document.__proto__.__proto__.constructor.name", "Document" },
+        .{ "document.body.localName == 'body'", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.domain", "lightpanda.io" },
+        .{ "document.referrer", "" },
+        .{ "document.title", "" },
+        .{ "document.body.localName", "body" },
+        .{ "document.head.localName", "head" },
+        .{ "document.images.length", "0" },
+        .{ "document.embeds.length", "0" },
+        .{ "document.plugins.length", "0" },
+        .{ "document.scripts.length", "0" },
+        .{ "document.forms.length", "0" },
+        .{ "document.links.length", "1" },
+        .{ "document.applets.length", "0" },
+        .{ "document.anchors.length", "0" },
+        .{ "document.all.length", "8" },
+        .{ "document.currentScript", "null" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.title = 'foo'", "foo" },
+        .{ "document.title", "foo" },
+        .{ "document.title = ''", "" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.getElementById('link').setAttribute('name', 'foo')", "undefined" },
+        .{ "let list = document.getElementsByName('foo')", "undefined" },
+        .{ "list.length", "1" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.cookie", "" },
+        .{ "document.cookie = 'name=Oeschger; SameSite=None; Secure'", "name=Oeschger; SameSite=None; Secure" },
+        .{ "document.cookie = 'favorite_food=tripe; SameSite=None; Secure'", "favorite_food=tripe; SameSite=None; Secure" },
+        .{ "document.cookie", "name=Oeschger; favorite_food=tripe" },
+        .{ "document.cookie = 'IgnoreMy=Ghost; HttpOnly'", null }, // "" should be returned, but the framework overrules it atm
+        .{ "document.cookie", "name=Oeschger; favorite_food=tripe" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.elementFromPoint(0.5, 0.5)", "null" }, //  Return null since we only return element s when they have previously been localized
+        .{ "document.elementsFromPoint(0.5, 0.5)", "" },
+        .{
+            \\ let div1 = document.createElement('div');
+            \\ document.body.appendChild(div1);
+            \\ div1.getClientRects();
+            ,
+            null,
+        },
+        .{ "document.elementFromPoint(0.5, 0.5)", "[object HTMLDivElement]" },
+        .{ "let elems = document.elementsFromPoint(0.5, 0.5)", null },
+        .{ "elems.length", "3" },
+        .{ "elems[0]", "[object HTMLDivElement]" },
+        .{ "elems[1]", "[object HTMLBodyElement]" },
+        .{ "elems[2]", "[object HTMLHtmlElement]" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{
+            \\ let a = document.createElement('a');
+            \\ a.href = "https://lightpanda.io";
+            \\ document.body.appendChild(a);
+            \\ a.getClientRects();
+            , // Note this will be placed after the div of previous test
+            null,
+        },
+        .{ "let a_again = document.elementFromPoint(1.5, 0.5)", null },
+        .{ "a_again", "[object HTMLAnchorElement]" },
+        .{ "a_again.href", "https://lightpanda.io" },
+        .{ "let a_agains = document.elementsFromPoint(1.5, 0.5)", null },
+        .{ "a_agains[0].href", "https://lightpanda.io" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "!document.all", "true" },
+        .{ "!!document.all", "false" },
+        .{ "document.all(5)", "[object HTMLParagraphElement]" },
+        .{ "document.all('content')", "[object HTMLDivElement]" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.defaultView.document == document", "true" },
+    }, .{});
+
+    try runner.testCases(&.{
+        .{ "document.readyState", "loading" },
+    }, .{});
+
+    try HTMLDocument.documentIsLoaded(runner.page.window.document, runner.page);
+    try runner.testCases(&.{
+        .{ "document.readyState", "interactive" },
+    }, .{});
+
+    try HTMLDocument.documentIsComplete(runner.page.window.document, runner.page);
+    try runner.testCases(&.{
+        .{ "document.readyState", "complete" },
+    }, .{});
+}
--- a/src/browser/html/elements.zig
+++ b/src/browser/html/elements.zig
--- a/src/browser/html/error_event.zig
+++ b/src/browser/html/error_event.zig
@@ -0,0 +1,114 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+const Env = @import("../env.zig").Env;
+const parser = @import("../netsurf.zig");
+
+// https://developer.mozilla.org/en-US/docs/Web/API/ErrorEvent
+pub const ErrorEvent = struct {
+    pub const prototype = *parser.Event;
+    pub const union_make_copy = true;
+
+    proto: parser.Event,
+    message: []const u8,
+    filename: []const u8,
+    lineno: i32,
+    colno: i32,
+    @"error": ?Env.JsObject,
+
+    const ErrorEventInit = struct {
+        message: []const u8 = "",
+        filename: []const u8 = "",
+        lineno: i32 = 0,
+        colno: i32 = 0,
+        @"error": ?Env.JsObject = null,
+    };
+
+    pub fn constructor(event_type: []const u8, opts: ?ErrorEventInit) !ErrorEvent {
+        const event = try parser.eventCreate();
+        defer parser.eventDestroy(event);
+        try parser.eventInit(event, event_type, .{});
+        try parser.eventSetInternalType(event, .event);
+
+        const o = opts orelse ErrorEventInit{};
+
+        return .{
+            .proto = event.*,
+            .message = o.message,
+            .filename = o.filename,
+            .lineno = o.lineno,
+            .colno = o.colno,
+            .@"error" = if (o.@"error") |e| try e.persist() else null,
+        };
+    }
+
+    pub fn get_message(self: *const ErrorEvent) []const u8 {
+        return self.message;
+    }
+
+    pub fn get_filename(self: *const ErrorEvent) []const u8 {
+        return self.filename;
+    }
+
+    pub fn get_lineno(self: *const ErrorEvent) i32 {
+        return self.lineno;
+    }
+
+    pub fn get_colno(self: *const ErrorEvent) i32 {
+        return self.colno;
+    }
+
+    pub fn get_error(self: *const ErrorEvent) Env.UndefinedOr(Env.JsObject) {
+        if (self.@"error") |e| {
+            return .{ .value = e };
+        }
+        return .undefined;
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.ErrorEvent" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{ .html = "<div id=c></div>" });
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "let e1 = new ErrorEvent('err1')", null },
+        .{ "e1.message", "" },
+        .{ "e1.filename", "" },
+        .{ "e1.lineno", "0" },
+        .{ "e1.colno", "0" },
+        .{ "e1.error", "undefined" },
+
+        .{
+            \\ let e2 = new ErrorEvent('err1', {
+            \\    message: 'm1',
+            \\    filename: 'fx19',
+            \\    lineno: 443,
+            \\    colno: 8999,
+            \\    error: 'under 9000!',
+            \\
+            \\})
+            ,
+            null,
+        },
+        .{ "e2.message", "m1" },
+        .{ "e2.filename", "fx19" },
+        .{ "e2.lineno", "443" },
+        .{ "e2.colno", "8999" },
+        .{ "e2.error", "under 9000!" },
+    }, .{});
+}
--- a/src/browser/html/form.zig
+++ b/src/browser/html/form.zig
@@ -0,0 +1,38 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+const std = @import("std");
+const Allocator = std.mem.Allocator;
+
+const parser = @import("../netsurf.zig");
+const Page = @import("../page.zig").Page;
+const HTMLElement = @import("elements.zig").HTMLElement;
+const FormData = @import("../xhr/form_data.zig").FormData;
+
+pub const HTMLFormElement = struct {
+    pub const Self = parser.Form;
+    pub const prototype = *HTMLElement;
+    pub const subtype = .node;
+
+    pub fn _submit(self: *parser.Form, page: *Page) !void {
+        return page.submitForm(self, null);
+    }
+
+    pub fn _reset(self: *parser.Form) !void {
+        try parser.formElementReset(self);
+    }
+};
--- a/src/browser/html/history.zig
+++ b/src/browser/html/history.zig
@@ -0,0 +1,120 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+// https://html.spec.whatwg.org/multipage/nav-history-apis.html#the-history-interface
+pub const History = struct {
+    const ScrollRestorationMode = enum {
+        auto,
+        manual,
+    };
+
+    scrollRestoration: ScrollRestorationMode = .auto,
+    state: std.json.Value = .null,
+
+    // count tracks the history length until we implement correctly pushstate.
+    count: u32 = 0,
+
+    pub fn get_length(self: *History) u32 {
+        // TODO return the real history length value.
+        return self.count;
+    }
+
+    pub fn get_scrollRestoration(self: *History) []const u8 {
+        return switch (self.scrollRestoration) {
+            .auto => "auto",
+            .manual => "manual",
+        };
+    }
+
+    pub fn set_scrollRestoration(self: *History, mode: []const u8) void {
+        if (std.mem.eql(u8, "manual", mode)) self.scrollRestoration = .manual;
+        if (std.mem.eql(u8, "auto", mode)) self.scrollRestoration = .auto;
+    }
+
+    pub fn get_state(self: *History) std.json.Value {
+        return self.state;
+    }
+
+    // TODO implement the function
+    // data must handle any argument. We could expect a std.json.Value but
+    // https://github.com/lightpanda-io/zig-js-runtime/issues/267 is missing.
+    pub fn _pushState(self: *History, data: []const u8, _: ?[]const u8, url: ?[]const u8) void {
+        self.count += 1;
+        _ = url;
+        _ = data;
+    }
+
+    // TODO implement the function
+    // data must handle any argument. We could expect a std.json.Value but
+    // https://github.com/lightpanda-io/zig-js-runtime/issues/267 is missing.
+    pub fn _replaceState(self: *History, data: []const u8, _: ?[]const u8, url: ?[]const u8) void {
+        _ = self;
+        _ = url;
+        _ = data;
+    }
+
+    // TODO implement the function
+    pub fn _go(self: *History, delta: ?i32) void {
+        _ = self;
+        _ = delta;
+    }
+
+    // TODO implement the function
+    pub fn _back(self: *History) void {
+        _ = self;
+    }
+
+    // TODO implement the function
+    pub fn _forward(self: *History) void {
+        _ = self;
+    }
+};
+
+// Tests
+// -----
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.History" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "history.scrollRestoration", "auto" },
+        .{ "history.scrollRestoration = 'manual'", "manual" },
+        .{ "history.scrollRestoration = 'foo'", "foo" },
+        .{ "history.scrollRestoration", "manual" },
+        .{ "history.scrollRestoration = 'auto'", "auto" },
+        .{ "history.scrollRestoration", "auto" },
+
+        .{ "history.state", "null" },
+
+        .{ "history.pushState({}, null, '')", "undefined" },
+
+        .{ "history.replaceState({}, null, '')", "undefined" },
+
+        .{ "history.go()", "undefined" },
+        .{ "history.go(1)", "undefined" },
+        .{ "history.go(-1)", "undefined" },
+
+        .{ "history.forward()", "undefined" },
+
+        .{ "history.back()", "undefined" },
+    }, .{});
+}
--- a/src/browser/html/html.zig
+++ b/src/browser/html/html.zig
@@ -0,0 +1,43 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const HTMLDocument = @import("document.zig").HTMLDocument;
+const HTMLElem = @import("elements.zig");
+const SVGElem = @import("svg_elements.zig");
+const Window = @import("window.zig").Window;
+const Navigator = @import("navigator.zig").Navigator;
+const History = @import("history.zig").History;
+const Location = @import("location.zig").Location;
+const MediaQueryList = @import("media_query_list.zig").MediaQueryList;
+
+pub const Interfaces = .{
+    HTMLDocument,
+    HTMLElem.HTMLElement,
+    HTMLElem.HTMLMediaElement,
+    HTMLElem.Interfaces,
+    SVGElem.SVGElement,
+    Window,
+    Navigator,
+    History,
+    Location,
+    MediaQueryList,
+    @import("DataSet.zig"),
+    @import("screen.zig").Interfaces,
+    @import("error_event.zig").ErrorEvent,
+    @import("AbortController.zig").Interfaces,
+};
--- a/src/browser/html/location.zig
+++ b/src/browser/html/location.zig
@@ -0,0 +1,106 @@
+// Copyright (C) 2023-2024  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const Page = @import("../page.zig").Page;
+
+const URL = @import("../url/url.zig").URL;
+
+// https://html.spec.whatwg.org/multipage/nav-history-apis.html#the-location-interface
+pub const Location = struct {
+    url: ?URL = null,
+
+    pub fn get_href(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_href(page);
+        return "";
+    }
+
+    pub fn get_protocol(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_protocol(page);
+        return "";
+    }
+
+    pub fn get_host(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_host(page);
+        return "";
+    }
+
+    pub fn get_hostname(self: *Location) []const u8 {
+        if (self.url) |*u| return u.get_hostname();
+        return "";
+    }
+
+    pub fn get_port(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_port(page);
+        return "";
+    }
+
+    pub fn get_pathname(self: *Location) []const u8 {
+        if (self.url) |*u| return u.get_pathname();
+        return "";
+    }
+
+    pub fn get_search(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_search(page);
+        return "";
+    }
+
+    pub fn get_hash(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_hash(page);
+        return "";
+    }
+
+    pub fn get_origin(self: *Location, page: *Page) ![]const u8 {
+        if (self.url) |*u| return u.get_origin(page);
+        return "";
+    }
+
+    pub fn _assign(_: *const Location, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url, .{ .reason = .script });
+    }
+
+    pub fn _replace(_: *const Location, url: []const u8, page: *Page) !void {
+        return page.navigateFromWebAPI(url, .{ .reason = .script });
+    }
+
+    pub fn _reload(_: *const Location, page: *Page) !void {
+        return page.navigateFromWebAPI(page.url.raw, .{ .reason = .script });
+    }
+
+    pub fn _toString(self: *Location, page: *Page) ![]const u8 {
+        return try self.get_href(page);
+    }
+};
+
+const testing = @import("../../testing.zig");
+test "Browser.HTML.Location" {
+    var runner = try testing.jsRunner(testing.tracking_allocator, .{});
+    defer runner.deinit();
+
+    try runner.testCases(&.{
+        .{ "location.href", "https://lightpanda.io/opensource-browser/" },
+        .{ "document.location.href", "https://lightpanda.io/opensource-browser/" },
+
+        .{ "location.host", "lightpanda.io" },
+        .{ "location.hostname", "lightpanda.io" },
+        .{ "location.origin", "https://lightpanda.io" },
+        .{ "location.pathname", "/opensource-browser/" },
+        .{ "location.hash", "" },
+        .{ "location.port", "" },
+        .{ "location.search", "" },
+    }, .{});
+}
--- a/src/browser/html/media_query_list.zig
+++ b/src/browser/html/media_query_list.zig
@@ -0,0 +1,45 @@
+// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const parser = @import("../netsurf.zig");
+const Function = @import("../env.zig").Function;
+const EventTarget = @import("../dom/event_target.zig").EventTarget;
+
+// https://drafts.csswg.org/cssom-view/#the-mediaquerylist-interface
+pub const MediaQueryList = struct {
+    pub const prototype = *EventTarget;
+
+    // Extend libdom event target for pure zig struct.
+    // This is not safe as it relies on a structure layout that isn't guaranteed
+    base: parser.EventTargetTBase = parser.EventTargetTBase{ .internal_target_type = .media_query_list },
+
+    matches: bool,
+    media: []const u8,
+
+    pub fn get_matches(self: *const MediaQueryList) bool {
+        return self.matches;
+    }
+
+    pub fn get_media(self: *const MediaQueryList) []const u8 {
+        return self.media;
+    }
+
+    pub fn _addListener(_: *const MediaQueryList, _: Function) void {}
+
+    pub fn _removeListener(_: *const MediaQueryList, _: Function) void {}
+};
--- a/Show More
+++ b/Show More