Replace epoll to poll

ci: for wpt run with --concurrency=3

.github/actions/install/action.yml

@@ -13,7 +13,7 @@ inputs:
   zig-v8:
     description: 'zig v8 version to install'
     required: false
-    default: 'v0.2.9'
+    default: 'v0.3.1'
   v8:
     description: 'v8 version to install'
     required: false

.github/workflows/e2e-integration-test.yml

@@ -63,6 +63,6 @@ jobs:
 
       - name: run end to end integration tests
         run: |
-          ./lightpanda serve & echo $! > LPD.pid
+          ./lightpanda serve --log_level error & echo $! > LPD.pid
           go run integration/main.go
           kill `cat LPD.pid`

.github/workflows/wpt.yml

@@ -15,11 +15,11 @@ on:
   workflow_dispatch:
 
 jobs:
-  wpt:
-    name: web platform tests json output
+  wpt-build-release:
+    name: zig build release
 
     runs-on: ubuntu-latest
-    timeout-minutes: 90
+    timeout-minutes: 15
 
     steps:
       - uses: actions/checkout@v6
@@ -30,11 +30,85 @@ jobs:
 
       - uses: ./.github/actions/install
 
-      - name: build wpt
-        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -- version
+      - name: zig build release
+        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64 -Dgit_commit=$(git rev-parse --short ${{ github.sha }})
+
+      - name: upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: lightpanda-build-release
+          path: |
+            zig-out/bin/lightpanda
+          retention-days: 1
+
+  wpt-build-runner:
+    name: build wpt runner
+
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          repository: 'lightpanda-io/demo'
+          fetch-depth: 0
+
+      - run: |
+          cd ./wptrunner
+          CGO_ENABLED=0 go build
+
+      - name: upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: wptrunner
+          path: |
+            wptrunner/wptrunner
+          retention-days: 1
+
+  run-wpt:
+    name: web platform tests json output
+    needs:
+      - wpt-build-release
+      - wpt-build-runner
+
+    # use a self host runner.
+    runs-on: lpd-bench-hetzner
+    timeout-minutes: 120
+
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          ref: fork
+          repository: 'lightpanda-io/wpt'
+          fetch-depth: 0
+
+      # The hosts are configured manually on the self host runner.
+      # - name: create custom hosts
+      #   run: ./wpt make-hosts-file | sudo tee -a /etc/hosts
+
+      - name: generate manifest
+        run: ./wpt manifest
+
+      - name: download lightpanda release
+        uses: actions/download-artifact@v4
+        with:
+          name: lightpanda-build-release
+
+      - run: chmod a+x ./lightpanda
+
+      - name: download wptrunner
+        uses: actions/download-artifact@v4
+        with:
+          name: wptrunner
+
+      - run: chmod a+x ./wptrunner
 
       - name: run test with json output
-        run:  zig-out/bin/lightpanda-wpt --json > wpt.json
+        run: |
+          ./wpt serve 2> /dev/null & echo $! > WPT.pid
+          sleep 10s
+          ./wptrunner -lpd-path ./lightpanda -json -concurrency 3 > wpt.json
+          kill `cat WPT.pid`
 
       - name: write commit
         run: |
@@ -51,7 +125,7 @@ jobs:
 
   perf-fmt:
     name: perf-fmt
-    needs: wpt
+    needs: run-wpt
 
     runs-on: ubuntu-latest
     timeout-minutes: 15

.gitignore

@@ -1,11 +1,6 @@
-zig-cache
 /.zig-cache/
 /.lp-cache/
 zig-out
-/vendor/netsurf/out
-/vendor/libiconv/
 lightpanda.id
-/v8/
-/build/
 /src/html5ever/target/
 src/snapshot.bin

.gitmodules

@@ -1,15 +0,0 @@
-[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/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

Dockerfile

@@ -3,7 +3,7 @@ FROM debian:stable-slim
 ARG MINISIG=0.12
 ARG ZIG_MINISIG=RWSGOq2NVecA2UPNdBUZykf1CCb147pkmdtYxgb3Ti+JO/wCYvhbAb/U
 ARG V8=14.0.365.4
-ARG ZIG_V8=v0.2.9
+ARG ZIG_V8=v0.3.1
 ARG TARGETPLATFORM
 
 RUN apt-get update -yq && \

Makefile

@@ -47,7 +47,7 @@ help:
 
 # $(ZIG) commands
 # ------------
-.PHONY: build build-v8-snapshot build-dev run run-release shell test bench wpt data end2end
+.PHONY: build build-v8-snapshot build-dev run run-release shell test bench data end2end
 
 ## Build v8 snapshot
 build-v8-snapshot:
@@ -82,15 +82,6 @@ shell:
 	@printf "\033[36mBuilding shell...\033[0m\n"
 	@$(ZIG) build shell || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
 
-## Run WPT tests
-wpt:
-	@printf "\033[36mBuilding wpt...\033[0m\n"
-	@$(ZIG) build wpt -- $(filter-out $@,$(MAKECMDGOALS)) || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
-
-wpt-summary:
-	@printf "\033[36mBuilding wpt...\033[0m\n"
-	@$(ZIG) build wpt -- --summary $(filter-out $@,$(MAKECMDGOALS)) || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
-
 ## Test - `grep` is used to filter out the huge compile command on build
 ifeq ($(OS), macos)
 test:
@@ -111,13 +102,8 @@ end2end:
 # ------------
 .PHONY: install
 
-## Install and build dependencies for release
-install: install-submodule
+install: build
 
 data:
 	cd src/data && go run public_suffix_list_gen.go > public_suffix_list.zig
 
-## Init and update git submodule
-install-submodule:
-	@git submodule init && \
-	git submodule update

README.md

@@ -220,18 +220,6 @@ For **MacOS**, you need cmake and [Rust](https://rust-lang.org/tools/install/).
 brew install cmake
 ```
 
-### Install Git submodules
-
-The project uses git submodules for dependencies.
-
-To init or update the submodules in the `vendor/` directory:
-
-```
-make install-submodule
-```
-
-This is an alias for `git submodule init && git submodule update`.
-
 ### Build and run
 
 You an build the entire browser with `make build` or `make build-dev` for debug
@@ -281,35 +269,75 @@ make end2end
 Lightpanda is tested against the standardized [Web Platform
 Tests](https://web-platform-tests.org/).
 
-The relevant tests cases are committed in a [dedicated repository](https://github.com/lightpanda-io/wpt) which is fetched by the `make install-submodule` command.
-
-All the tests cases executed are located in the `tests/wpt` sub-directory.
+We use [a fork](https://github.com/lightpanda-io/wpt/tree/fork) including a custom
+[`testharnessreport.js`](https://github.com/lightpanda-io/wpt/commit/01a3115c076a3ad0c84849dbbf77a6e3d199c56f).
 
 For reference, you can easily execute a WPT test case with your browser via
 [wpt.live](https://wpt.live).
 
+#### Configure WPT HTTP server
+
+To run the test, you must clone the repository, configure the custom hosts and generate the
+`MANIFEST.json` file.
+
+Clone the repository with the `fork` branch.
+```
+git clone -b fork --depth=1 git@github.com:lightpanda-io/wpt.git
+```
+
+Enter into the `wpt/` dir.
+
+Install custom domains in your `/etc/hosts`
+```
+./wpt make-hosts-file | sudo tee -a /etc/hosts
+```
+
+Generate `MANIFEST.json`
+```
+./wpt manifest
+```
+Use the [WPT's setup
+guide](https://web-platform-tests.org/running-tests/from-local-system.html) for
+details.
+
 #### Run WPT test suite
 
-To run all the tests:
+An external [Go](https://go.dev) runner is provided by
+[github.com/lightpanda-io/demo/](https://github.com/lightpanda-io/demo/)
+repository, located into `wptrunner/` dir.
+You need to clone the project first.
+
+First start the WPT's HTTP server from your `wpt/` clone dir.
+```
+./wpt serve
+```
+
+Run a Lightpanda browser
 
 ```
-make wpt
+zig build run -- --insecure_disable_tls_host_verification
+```
+
+Then you can start the wptrunner from the Demo's clone dir:
+```
+cd wptrunner && go run .
 ```
 
 Or one specific test:
 
 ```
-make wpt Node-childNodes.html
+cd wptrunner && go run . Node-childNodes.html
 ```
 
-#### Add a new WPT test case
+`wptrunner` command accepts `--summary` and `--json` options modifying output.
+Also `--concurrency` define the concurrency limit.
 
-We add new relevant tests cases files when we implemented changes in Lightpanda.
+:warning: Running the whole test suite will take a long time. In this case,
+it's useful to build in `releaseFast` mode to make tests faster.
 
-To add a new test, copy the file you want from the [WPT
-repo](https://github.com/web-platform-tests/wpt) into the `tests/wpt` directory.
-
-:warning: Please keep the original directory tree structure of `tests/wpt`.
+```
+zig build -Doptimize=ReleaseFast run
+```
 
 ## Contributing
 

build.zig.zon

@@ -1,18 +1,36 @@
 .{
     .name = .browser,
-    .paths = .{""},
     .version = "0.0.0",
     .fingerprint = 0xda130f3af836cea0, // Changing this has security and trust implications.
     .minimum_zig_version = "0.15.2",
     .dependencies = .{
         .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/refs/tags/v0.2.9.tar.gz",
-            .hash = "v8-0.0.0-xddH689vBACgpqFVEhT2wxRin-qQQSOcKJoM37MVo0rU",
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/refs/tags/v0.3.1.tar.gz",
+            .hash = "v8-0.0.0-xddH64J7BAC81mkf6G9RbEJxS-W3TIRl5iFnShwbqCqy",
+
         },
         //.v8 = .{ .path = "../zig-v8-fork" },
+        .brotli = .{
+            // v1.2.0
+            .url = "https://github.com/google/brotli/archive/028fb5a23661f123017c060daa546b55cf4bde29.tar.gz",
+            .hash = "N-V-__8AAJudKgCQCuIiH6MJjAiIJHfg_tT_Ew-0vZwVkCo_",
+        },
+        .zlib = .{
+            .url = "https://github.com/madler/zlib/releases/download/v1.3.2/zlib-1.3.2.tar.gz",
+            .hash = "N-V-__8AAJ2cNgAgfBtAw33Bxfu1IWISDeKKSr3DAqoAysIJ",
+        },
+        .nghttp2 = .{
+            .url = "https://github.com/nghttp2/nghttp2/releases/download/v1.68.0/nghttp2-1.68.0.tar.gz",
+            .hash = "N-V-__8AAL15vQCI63ZL6Zaz5hJg6JTEgYXGbLnMFSnf7FT3",
+        },
         .@"boringssl-zig" = .{
             .url = "git+https://github.com/Syndica/boringssl-zig.git#c53df00d06b02b755ad88bbf4d1202ed9687b096",
             .hash = "boringssl-0.1.0-VtJeWehMAAA4RNnwRnzEvKcS9rjsR1QVRw1uJrwXxmVK",
         },
+        .curl = .{
+            .url = "https://github.com/curl/curl/releases/download/curl-8_18_0/curl-8.18.0.tar.gz",
+            .hash = "N-V-__8AALp9QAGn6CCHZ6fK_FfMyGtG824LSHYHHasM3w-y",
+        },
     },
+    .paths = .{""},
 }

src/App.zig

@@ -66,7 +66,7 @@ pub fn init(allocator: Allocator, config: *const Config) !*App {
     app.telemetry = try Telemetry.init(app, config.mode);
     errdefer app.telemetry.deinit();
 
-    app.arena_pool = ArenaPool.init(allocator);
+    app.arena_pool = ArenaPool.init(allocator, 512, 1024 * 16);
     errdefer app.arena_pool.deinit();
 
     return app;

src/ArenaPool.zig

@@ -36,12 +36,12 @@ const Entry = struct {
     arena: ArenaAllocator,
 };
 
-pub fn init(allocator: Allocator) ArenaPool {
+pub fn init(allocator: Allocator, free_list_max: u16, retain_bytes: usize) ArenaPool {
     return .{
         .allocator = allocator,
-        .free_list_max = 512, //  TODO make configurable
-        .retain_bytes = 1024 * 16, // TODO make configurable
-        .entry_pool = std.heap.MemoryPool(Entry).init(allocator),
+        .free_list_max = free_list_max,
+        .retain_bytes = retain_bytes,
+        .entry_pool = .init(allocator),
     };
 }
 
@@ -99,3 +99,114 @@ pub fn reset(_: *const ArenaPool, allocator: Allocator, retain: usize) void {
     const arena: *std.heap.ArenaAllocator = @ptrCast(@alignCast(allocator.ptr));
     _ = arena.reset(.{ .retain_with_limit = retain });
 }
+
+const testing = std.testing;
+
+test "arena pool - basic acquire and use" {
+    var pool = ArenaPool.init(testing.allocator, 512, 1024 * 16);
+    defer pool.deinit();
+
+    const alloc = try pool.acquire();
+    const buf = try alloc.alloc(u8, 64);
+    @memset(buf, 0xAB);
+    try testing.expectEqual(@as(u8, 0xAB), buf[0]);
+
+    pool.release(alloc);
+}
+
+test "arena pool - reuse entry after release" {
+    var pool = ArenaPool.init(testing.allocator, 512, 1024 * 16);
+    defer pool.deinit();
+
+    const alloc1 = try pool.acquire();
+    try testing.expectEqual(@as(u16, 0), pool.free_list_len);
+
+    pool.release(alloc1);
+    try testing.expectEqual(@as(u16, 1), pool.free_list_len);
+
+    // The same entry should be returned from the free list.
+    const alloc2 = try pool.acquire();
+    try testing.expectEqual(@as(u16, 0), pool.free_list_len);
+    try testing.expectEqual(alloc1.ptr, alloc2.ptr);
+
+    pool.release(alloc2);
+}
+
+test "arena pool - multiple concurrent arenas" {
+    var pool = ArenaPool.init(testing.allocator, 512, 1024 * 16);
+    defer pool.deinit();
+
+    const a1 = try pool.acquire();
+    const a2 = try pool.acquire();
+    const a3 = try pool.acquire();
+
+    // All three must be distinct arenas.
+    try testing.expect(a1.ptr != a2.ptr);
+    try testing.expect(a2.ptr != a3.ptr);
+    try testing.expect(a1.ptr != a3.ptr);
+
+    _ = try a1.alloc(u8, 16);
+    _ = try a2.alloc(u8, 32);
+    _ = try a3.alloc(u8, 48);
+
+    pool.release(a1);
+    pool.release(a2);
+    pool.release(a3);
+
+    try testing.expectEqual(@as(u16, 3), pool.free_list_len);
+}
+
+test "arena pool - free list respects max limit" {
+    // Cap the free list at 1 so the second release discards its arena.
+    var pool = ArenaPool.init(testing.allocator, 1, 1024 * 16);
+    defer pool.deinit();
+
+    const a1 = try pool.acquire();
+    const a2 = try pool.acquire();
+
+    pool.release(a1);
+    try testing.expectEqual(@as(u16, 1), pool.free_list_len);
+
+    // The free list is full; a2's arena should be destroyed, not queued.
+    pool.release(a2);
+    try testing.expectEqual(@as(u16, 1), pool.free_list_len);
+}
+
+test "arena pool - reset clears memory without releasing" {
+    var pool = ArenaPool.init(testing.allocator, 512, 1024 * 16);
+    defer pool.deinit();
+
+    const alloc = try pool.acquire();
+
+    const buf = try alloc.alloc(u8, 128);
+    @memset(buf, 0xFF);
+
+    // reset() frees arena memory but keeps the allocator in-flight.
+    pool.reset(alloc, 0);
+
+    // The free list must stay empty; the allocator was not released.
+    try testing.expectEqual(@as(u16, 0), pool.free_list_len);
+
+    // Allocating again through the same arena must still work.
+    const buf2 = try alloc.alloc(u8, 64);
+    @memset(buf2, 0x00);
+    try testing.expectEqual(@as(u8, 0x00), buf2[0]);
+
+    pool.release(alloc);
+}
+
+test "arena pool - deinit with entries in free list" {
+    // Verifies that deinit properly cleans up free-listed arenas (no leaks
+    // detected by the test allocator).
+    var pool = ArenaPool.init(testing.allocator, 512, 1024 * 16);
+
+    const a1 = try pool.acquire();
+    const a2 = try pool.acquire();
+    _ = try a1.alloc(u8, 256);
+    _ = try a2.alloc(u8, 512);
+    pool.release(a1);
+    pool.release(a2);
+    try testing.expectEqual(@as(u16, 2), pool.free_list_len);
+
+    pool.deinit();
+}

src/Config.zig

@@ -28,6 +28,7 @@ pub const RunMode = enum {
     fetch,
     serve,
     version,
+    mcp,
 };
 
 pub const CDP_MAX_HTTP_REQUEST_SIZE = 4096;
@@ -59,56 +60,56 @@ pub fn deinit(self: *const Config, allocator: Allocator) void {
 
 pub fn tlsVerifyHost(self: *const Config) bool {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.tls_verify_host,
+        inline .serve, .fetch, .mcp => |opts| opts.common.tls_verify_host,
         else => unreachable,
     };
 }
 
 pub fn obeyRobots(self: *const Config) bool {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.obey_robots,
+        inline .serve, .fetch, .mcp => |opts| opts.common.obey_robots,
         else => unreachable,
     };
 }
 
 pub fn httpProxy(self: *const Config) ?[:0]const u8 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_proxy,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_proxy,
         else => unreachable,
     };
 }
 
 pub fn proxyBearerToken(self: *const Config) ?[:0]const u8 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.proxy_bearer_token,
+        inline .serve, .fetch, .mcp => |opts| opts.common.proxy_bearer_token,
         .help, .version => null,
     };
 }
 
 pub fn httpMaxConcurrent(self: *const Config) u8 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_max_concurrent orelse 10,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_max_concurrent orelse 10,
         else => unreachable,
     };
 }
 
 pub fn httpMaxHostOpen(self: *const Config) u8 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_max_host_open orelse 4,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_max_host_open orelse 4,
         else => unreachable,
     };
 }
 
 pub fn httpConnectTimeout(self: *const Config) u31 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_connect_timeout orelse 0,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_connect_timeout orelse 0,
         else => unreachable,
     };
 }
 
 pub fn httpTimeout(self: *const Config) u31 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_timeout orelse 5000,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_timeout orelse 5000,
         else => unreachable,
     };
 }
@@ -119,35 +120,35 @@ pub fn httpMaxRedirects(_: *const Config) u8 {
 
 pub fn httpMaxResponseSize(self: *const Config) ?usize {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.http_max_response_size,
+        inline .serve, .fetch, .mcp => |opts| opts.common.http_max_response_size,
         else => unreachable,
     };
 }
 
 pub fn logLevel(self: *const Config) ?log.Level {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.log_level,
+        inline .serve, .fetch, .mcp => |opts| opts.common.log_level,
         else => unreachable,
     };
 }
 
 pub fn logFormat(self: *const Config) ?log.Format {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.log_format,
+        inline .serve, .fetch, .mcp => |opts| opts.common.log_format,
         else => unreachable,
     };
 }
 
 pub fn logFilterScopes(self: *const Config) ?[]const log.Scope {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.log_filter_scopes,
+        inline .serve, .fetch, .mcp => |opts| opts.common.log_filter_scopes,
         else => unreachable,
     };
 }
 
 pub fn userAgentSuffix(self: *const Config) ?[]const u8 {
     return switch (self.mode) {
-        inline .serve, .fetch => |opts| opts.common.user_agent_suffix,
+        inline .serve, .fetch, .mcp => |opts| opts.common.user_agent_suffix,
         .help, .version => null,
     };
 }
@@ -171,6 +172,7 @@ pub const Mode = union(RunMode) {
     fetch: Fetch,
     serve: Serve,
     version: void,
+    mcp: Mcp,
 };
 
 pub const Serve = struct {
@@ -182,16 +184,22 @@ pub const Serve = struct {
     common: Common = .{},
 };
 
+pub const Mcp = struct {
+    common: Common = .{},
+};
+
 pub const DumpFormat = enum {
     html,
     markdown,
+    wpt,
 };
 
 pub const Fetch = struct {
     url: [:0]const u8,
     dump_mode: ?DumpFormat = null,
     common: Common = .{},
-    withbase: bool = false,
+    with_base: bool = false,
+    with_frames: bool = false,
     strip: dump.Opts.Strip = .{},
 };
 
@@ -322,7 +330,7 @@ pub fn printUsageAndExit(self: *const Config, success: bool) void {
     const usage =
         \\usage: {s} command [options] [URL]
         \\
-        \\Command can be either 'fetch', 'serve' or 'help'
+        \\Command can be either 'fetch', 'serve', 'mcp' or 'help'
         \\
         \\fetch command
         \\Fetches the specified URL
@@ -342,6 +350,8 @@ pub fn printUsageAndExit(self: *const Config, success: bool) void {
         \\
         \\--with_base     Add a <base> tag in dump. Defaults to false.
         \\
+        \\--with_frames   Includes the contents of iframes. Defaults to false.
+        \\
     ++ common_options ++
         \\
         \\serve command
@@ -366,6 +376,12 @@ pub fn printUsageAndExit(self: *const Config, success: bool) void {
         \\                Maximum pending connections in the accept queue.
         \\                Defaults to 128.
         \\
+    ++ common_options ++
+        \\
+        \\mcp command
+        \\Starts an MCP (Model Context Protocol) server over stdio
+        \\Example: {s} mcp
+        \\
     ++ common_options ++
         \\
         \\version command
@@ -375,7 +391,7 @@ pub fn printUsageAndExit(self: *const Config, success: bool) void {
         \\Displays this message
         \\
     ;
-    std.debug.print(usage, .{ self.exec_name, self.exec_name, self.exec_name, self.exec_name });
+    std.debug.print(usage, .{ self.exec_name, self.exec_name, self.exec_name, self.exec_name, self.exec_name });
     if (success) {
         return std.process.cleanExit();
     }
@@ -410,6 +426,8 @@ pub fn parseArgs(allocator: Allocator) !Config {
             return init(allocator, exec_name, .{ .help = false }) },
         .fetch => .{ .fetch = parseFetchArgs(allocator, &args) catch
             return init(allocator, exec_name, .{ .help = false }) },
+        .mcp => .{ .mcp = parseMcpArgs(allocator, &args) catch
+            return init(allocator, exec_name, .{ .help = false }) },
         .version => .{ .version = {} },
     };
     return init(allocator, exec_name, mode);
@@ -440,6 +458,10 @@ fn inferMode(opt: []const u8) ?RunMode {
         return .fetch;
     }
 
+    if (std.mem.eql(u8, opt, "--with_frames")) {
+        return .fetch;
+    }
+
     if (std.mem.eql(u8, opt, "--host")) {
         return .serve;
     }
@@ -534,12 +556,31 @@ fn parseServeArgs(
     return serve;
 }
 
+fn parseMcpArgs(
+    allocator: Allocator,
+    args: *std.process.ArgIterator,
+) !Mcp {
+    var mcp: Mcp = .{};
+
+    while (args.next()) |opt| {
+        if (try parseCommonArg(allocator, opt, args, &mcp.common)) {
+            continue;
+        }
+
+        log.fatal(.mcp, "unknown argument", .{ .mode = "mcp", .arg = opt });
+        return error.UnkownOption;
+    }
+
+    return mcp;
+}
+
 fn parseFetchArgs(
     allocator: Allocator,
     args: *std.process.ArgIterator,
 ) !Fetch {
     var dump_mode: ?DumpFormat = null;
-    var withbase: bool = false;
+    var with_base: bool = false;
+    var with_frames: bool = false;
     var url: ?[:0]const u8 = null;
     var common: Common = .{};
     var strip: dump.Opts.Strip = .{};
@@ -570,7 +611,12 @@ fn parseFetchArgs(
         }
 
         if (std.mem.eql(u8, "--with_base", opt)) {
-            withbase = true;
+            with_base = true;
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--with_frames", opt)) {
+            with_frames = true;
             continue;
         }
 
@@ -626,7 +672,8 @@ fn parseFetchArgs(
         .dump_mode = dump_mode,
         .strip = strip,
         .common = common,
-        .withbase = withbase,
+        .with_base = with_base,
+        .with_frames = with_frames,
     };
 }
 

src/Notification.zig

@@ -73,6 +73,7 @@ const EventListeners = struct {
     page_navigated: List = .{},
     page_network_idle: List = .{},
     page_network_almost_idle: List = .{},
+    page_frame_created: List = .{},
     http_request_fail: List = .{},
     http_request_start: List = .{},
     http_request_intercept: List = .{},
@@ -89,6 +90,7 @@ const Events = union(enum) {
     page_navigated: *const PageNavigated,
     page_network_idle: *const PageNetworkIdle,
     page_network_almost_idle: *const PageNetworkAlmostIdle,
+    page_frame_created: *const PageFrameCreated,
     http_request_fail: *const RequestFail,
     http_request_start: *const RequestStart,
     http_request_intercept: *const RequestIntercept,
@@ -102,24 +104,36 @@ const EventType = std.meta.FieldEnum(Events);
 pub const PageRemove = struct {};
 
 pub const PageNavigate = struct {
-    req_id: usize,
+    req_id: u32,
+    frame_id: u32,
     timestamp: u64,
     url: [:0]const u8,
     opts: Page.NavigateOpts,
 };
 
 pub const PageNavigated = struct {
-    req_id: usize,
+    req_id: u32,
+    frame_id: u32,
     timestamp: u64,
     url: [:0]const u8,
     opts: Page.NavigatedOpts,
 };
 
 pub const PageNetworkIdle = struct {
+    req_id: u32,
+    frame_id: u32,
     timestamp: u64,
 };
 
 pub const PageNetworkAlmostIdle = struct {
+    req_id: u32,
+    frame_id: u32,
+    timestamp: u64,
+};
+
+pub const PageFrameCreated = struct {
+    frame_id: u32,
+    parent_id: u32,
     timestamp: u64,
 };
 
@@ -305,6 +319,7 @@ test "Notification" {
 
     // noop
     notifier.dispatch(.page_navigate, &.{
+        .frame_id = 0,
         .req_id = 1,
         .timestamp = 4,
         .url = undefined,
@@ -315,6 +330,7 @@ test "Notification" {
 
     try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
     notifier.dispatch(.page_navigate, &.{
+        .frame_id = 0,
         .req_id = 1,
         .timestamp = 4,
         .url = undefined,
@@ -324,6 +340,7 @@ test "Notification" {
 
     notifier.unregisterAll(&tc);
     notifier.dispatch(.page_navigate, &.{
+        .frame_id = 0,
         .req_id = 1,
         .timestamp = 10,
         .url = undefined,
@@ -334,23 +351,25 @@ test "Notification" {
     try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
     try notifier.register(.page_navigated, &tc, TestClient.pageNavigated);
     notifier.dispatch(.page_navigate, &.{
+        .frame_id = 0,
         .req_id = 1,
         .timestamp = 10,
         .url = undefined,
         .opts = .{},
     });
-    notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 6, .url = undefined, .opts = .{} });
+    notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 6, .url = undefined, .opts = .{} });
     try testing.expectEqual(14, tc.page_navigate);
     try testing.expectEqual(6, tc.page_navigated);
 
     notifier.unregisterAll(&tc);
     notifier.dispatch(.page_navigate, &.{
+        .frame_id = 0,
         .req_id = 1,
         .timestamp = 100,
         .url = undefined,
         .opts = .{},
     });
-    notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
+    notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
     try testing.expectEqual(14, tc.page_navigate);
     try testing.expectEqual(6, tc.page_navigated);
 
@@ -358,27 +377,27 @@ test "Notification" {
         // unregister
         try notifier.register(.page_navigate, &tc, TestClient.pageNavigate);
         try notifier.register(.page_navigated, &tc, TestClient.pageNavigated);
-        notifier.dispatch(.page_navigate, &.{ .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigate, &.{ .frame_id = 0, .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
         try testing.expectEqual(114, tc.page_navigate);
         try testing.expectEqual(1006, tc.page_navigated);
 
         notifier.unregister(.page_navigate, &tc);
-        notifier.dispatch(.page_navigate, &.{ .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigate, &.{ .frame_id = 0, .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
         try testing.expectEqual(114, tc.page_navigate);
         try testing.expectEqual(2006, tc.page_navigated);
 
         notifier.unregister(.page_navigated, &tc);
-        notifier.dispatch(.page_navigate, &.{ .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigate, &.{ .frame_id = 0, .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
         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, &.{ .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
-        notifier.dispatch(.page_navigated, &.{ .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigate, &.{ .frame_id = 0, .req_id = 1, .timestamp = 100, .url = undefined, .opts = .{} });
+        notifier.dispatch(.page_navigated, &.{ .frame_id = 0, .req_id = 1, .timestamp = 1000, .url = undefined, .opts = .{} });
         try testing.expectEqual(114, tc.page_navigate);
         try testing.expectEqual(2006, tc.page_navigated);
     }

src/Server.zig

@@ -30,6 +30,7 @@ const log = @import("log.zig");
 const App = @import("App.zig");
 const Config = @import("Config.zig");
 const CDP = @import("cdp/cdp.zig").CDP;
+const Net = @import("Net.zig");
 const Http = @import("http/Http.zig");
 const HttpClient = @import("http/Client.zig");
 
@@ -120,26 +121,52 @@ pub fn run(self: *Server, address: net.Address, timeout_ms: u32) !void {
     try posix.listen(listener, self.app.config.maxPendingConnections());
 
     log.info(.app, "server running", .{ .address = address });
-    while (!self.shutdown.load(.acquire)) {
-        const socket = posix.accept(listener, null, null, posix.SOCK.NONBLOCK) catch |err| {
-            switch (err) {
-                error.SocketNotListening, error.ConnectionAborted => {
-                    log.info(.app, "server stopped", .{});
-                    break;
-                },
-                error.WouldBlock => {
-                    std.Thread.sleep(10 * std.time.ns_per_ms);
-                    continue;
-                },
-                else => {
-                    log.err(.app, "CDP accept", .{ .err = err });
-                    std.Thread.sleep(std.time.ns_per_s);
-                    continue;
-                },
-            }
+
+    var runtime = try Net.Runtime.init(self.allocator);
+    defer runtime.deinit();
+
+    var accept_ctx: AcceptCtx = .{
+        .server = self,
+        .timeout_ms = timeout_ms,
+    };
+
+    try runtime.add(listener, Net.Runtime.READABLE, &accept_ctx, onListenerEvent);
+    defer runtime.remove(listener);
+
+    runtime.run(self, shouldStopRuntime) catch |err| {
+        return err;
+    };
+
+    log.info(.app, "server stopped", .{});
+}
+
+const AcceptCtx = struct {
+    server: *Server,
+    timeout_ms: u32,
+};
+
+fn shouldStopRuntime(ctx: *anyopaque) bool {
+    const self: *Server = @ptrCast(@alignCast(ctx));
+    return self.shutdown.load(.acquire);
+}
+
+fn onListenerEvent(ctx: *anyopaque, event: Net.RuntimeEvent) !void {
+    _ = event;
+    const accept_ctx: *AcceptCtx = @ptrCast(@alignCast(ctx));
+    const self = accept_ctx.server;
+    const listener = self.listener orelse return;
+
+    while (true) {
+        const socket = posix.accept(listener, null, null, posix.SOCK.NONBLOCK) catch |err| switch (err) {
+            error.WouldBlock => return,
+            error.SocketNotListening, error.ConnectionAborted => return,
+            else => {
+                log.err(.app, "CDP accept", .{ .err = err });
+                return;
+            },
         };
 
-        self.spawnWorker(socket, timeout_ms) catch |err| {
+        self.spawnWorker(socket, accept_ctx.timeout_ms) catch |err| {
             log.err(.app, "CDP spawn", .{ .err = err });
             posix.close(socket);
         };
@@ -265,21 +292,7 @@ pub const Client = struct {
     allocator: Allocator,
     app: *App,
     http: *HttpClient,
-    json_version_response: []const u8,
-    reader: Reader(true),
-    socket: posix.socket_t,
-    socket_flags: usize,
-    send_arena: ArenaAllocator,
-    timeout_ms: u32,
-
-    const EMPTY_PONG = [_]u8{ 138, 0 };
-
-    // CLOSE, 2 length, code
-    const CLOSE_NORMAL = [_]u8{ 136, 2, 3, 232 }; // code: 1000
-    const CLOSE_TOO_BIG = [_]u8{ 136, 2, 3, 241 }; // 1009
-    const CLOSE_PROTOCOL_ERROR = [_]u8{ 136, 2, 3, 234 }; //code: 1002
-    // "private-use" close codes must be from 4000-49999
-    const CLOSE_TIMEOUT = [_]u8{ 136, 2, 15, 160 }; // code: 4000
+    ws: Net.WsConnection,
 
     fn init(
         socket: posix.socket_t,
@@ -288,40 +301,32 @@ pub const Client = struct {
         json_version_response: []const u8,
         timeout_ms: u32,
     ) !Client {
+        var ws = try Net.WsConnection.init(socket, allocator, json_version_response, timeout_ms);
+        errdefer ws.deinit();
+
         if (log.enabled(.app, .info)) {
-            var client_address: std.net.Address = undefined;
-            var socklen: posix.socklen_t = @sizeOf(net.Address);
-            try std.posix.getsockname(socket, &client_address.any, &socklen);
+            const client_address = ws.getAddress() catch null;
             log.info(.app, "client connected", .{ .ip = client_address });
         }
 
-        const socket_flags = try posix.fcntl(socket, posix.F.GETFL, 0);
-        const nonblocking = @as(u32, @bitCast(posix.O{ .NONBLOCK = true }));
-        // we expect the socket to come to us as nonblocking
-        lp.assert(socket_flags & nonblocking == nonblocking, "Client.init blocking", .{});
-
-        var reader = try Reader(true).init(allocator);
-        errdefer reader.deinit();
-
         const http = try app.http.createClient(allocator);
         errdefer http.deinit();
 
         return .{
-            .socket = socket,
             .allocator = allocator,
             .app = app,
             .http = http,
-            .json_version_response = json_version_response,
-            .reader = reader,
+            .ws = ws,
             .mode = .{ .http = {} },
-            .socket_flags = socket_flags,
-            .send_arena = ArenaAllocator.init(allocator),
-            .timeout_ms = timeout_ms,
         };
     }
 
     fn stop(self: *Client) void {
-        posix.shutdown(self.socket, .recv) catch {};
+        switch (self.mode) {
+            .http => {},
+            .cdp => |*cdp| cdp.browser.env.terminate(),
+        }
+        self.ws.shutdown();
     }
 
     fn deinit(self: *Client) void {
@@ -329,15 +334,14 @@ pub const Client = struct {
             .cdp => |*cdp| cdp.deinit(),
             .http => {},
         }
-        self.reader.deinit();
-        self.send_arena.deinit();
+        self.ws.deinit();
         self.http.deinit();
     }
 
     fn start(self: *Client) void {
         const http = self.http;
         http.cdp_client = .{
-            .socket = self.socket,
+            .socket = self.ws.socket,
             .ctx = self,
             .blocking_read_start = Client.blockingReadStart,
             .blocking_read = Client.blockingRead,
@@ -352,8 +356,9 @@ pub const Client = struct {
 
     fn httpLoop(self: *Client, http: *HttpClient) !void {
         lp.assert(self.mode == .http, "Client.httpLoop invalid mode", .{});
+
         while (true) {
-            const status = http.tick(self.timeout_ms) catch |err| {
+            const status = http.tick(self.ws.timeout_ms) catch |err| {
                 log.err(.app, "http tick", .{ .err = err });
                 return;
             };
@@ -371,13 +376,9 @@ pub const Client = struct {
             }
         }
 
-        return self.cdpLoop(http);
-    }
-
-    fn cdpLoop(self: *Client, http: *HttpClient) !void {
         var cdp = &self.mode.cdp;
         var last_message = timestamp(.monotonic);
-        var ms_remaining = self.timeout_ms;
+        var ms_remaining = self.ws.timeout_ms;
 
         while (true) {
             switch (cdp.pageWait(ms_remaining)) {
@@ -386,7 +387,7 @@ pub const Client = struct {
                         return;
                     }
                     last_message = timestamp(.monotonic);
-                    ms_remaining = self.timeout_ms;
+                    ms_remaining = self.ws.timeout_ms;
                 },
                 .no_page => {
                     const status = http.tick(ms_remaining) catch |err| {
@@ -401,7 +402,7 @@ pub const Client = struct {
                         return;
                     }
                     last_message = timestamp(.monotonic);
-                    ms_remaining = self.timeout_ms;
+                    ms_remaining = self.ws.timeout_ms;
                 },
                 .done => {
                     const elapsed = timestamp(.monotonic) - last_message;
@@ -417,7 +418,7 @@ pub const Client = struct {
 
     fn blockingReadStart(ctx: *anyopaque) bool {
         const self: *Client = @ptrCast(@alignCast(ctx));
-        _ = posix.fcntl(self.socket, posix.F.SETFL, self.socket_flags & ~@as(u32, @bitCast(posix.O{ .NONBLOCK = true }))) catch |err| {
+        self.ws.setBlocking(true) catch |err| {
             log.warn(.app, "CDP blockingReadStart", .{ .err = err });
             return false;
         };
@@ -431,7 +432,7 @@ pub const Client = struct {
 
     fn blockingReadStop(ctx: *anyopaque) bool {
         const self: *Client = @ptrCast(@alignCast(ctx));
-        _ = posix.fcntl(self.socket, posix.F.SETFL, self.socket_flags) catch |err| {
+        self.ws.setBlocking(false) catch |err| {
             log.warn(.app, "CDP blockingReadStop", .{ .err = err });
             return false;
         };
@@ -439,7 +440,7 @@ pub const Client = struct {
     }
 
     fn readSocket(self: *Client) bool {
-        const n = posix.read(self.socket, self.readBuf()) catch |err| {
+        const n = self.ws.read() catch |err| {
             log.warn(.app, "CDP read", .{ .err = err });
             return false;
         };
@@ -449,16 +450,10 @@ pub const Client = struct {
             return false;
         }
 
-        return self.processData(n) catch false;
+        return self.processData() catch false;
     }
 
-    fn readBuf(self: *Client) []u8 {
-        return self.reader.readBuf();
-    }
-
-    fn processData(self: *Client, len: usize) !bool {
-        self.reader.len += len;
-
+    fn processData(self: *Client) !bool {
         switch (self.mode) {
             .cdp => |*cdp| return self.processWebsocketMessage(cdp),
             .http => return self.processHTTPRequest(),
@@ -466,8 +461,8 @@ pub const Client = struct {
     }
 
     fn processHTTPRequest(self: *Client) !bool {
-        lp.assert(self.reader.pos == 0, "Client.HTTP pos", .{ .pos = self.reader.pos });
-        const request = self.reader.buf[0..self.reader.len];
+        lp.assert(self.ws.reader.pos == 0, "Client.HTTP pos", .{ .pos = self.ws.reader.pos });
+        const request = self.ws.reader.buf[0..self.ws.reader.len];
 
         if (request.len > Config.CDP_MAX_HTTP_REQUEST_SIZE) {
             self.writeHTTPErrorResponse(413, "Request too large");
@@ -481,7 +476,7 @@ pub const Client = struct {
         }
 
         // the next incoming data can go to the front of our buffer
-        defer self.reader.len = 0;
+        defer self.ws.reader.len = 0;
         return self.handleHTTPRequest(request) catch |err| {
             switch (err) {
                 error.NotFound => self.writeHTTPErrorResponse(404, "Not found"),
@@ -521,15 +516,15 @@ pub const Client = struct {
             return true;
         }
 
-        if (std.mem.eql(u8, url, "/json/version")) {
-            try self.send(self.json_version_response);
+        if (std.mem.eql(u8, url, "/json/version") or std.mem.eql(u8, url, "/json/version/")) {
+            try self.ws.send(self.ws.json_version_response);
             // Chromedp (a Go driver) does an http request to /json/version
             // then to / (websocket upgrade) using a different connection.
             // Since we only allow 1 connection at a time, the 2nd one (the
             // websocket upgrade) blocks until the first one times out.
             // We can avoid that by closing the connection. json_version_response
             // has a Connection: Close header too.
-            try posix.shutdown(self.socket, .recv);
+            self.ws.shutdown();
             return false;
         }
 
@@ -537,581 +532,31 @@ pub const Client = struct {
     }
 
     fn upgradeConnection(self: *Client, request: []u8) !void {
-        // our caller already confirmed that we have a trailing \r\n\r\n
-        const request_line_end = std.mem.indexOfScalar(u8, request, '\r') orelse unreachable;
-        const request_line = request[0..request_line_end];
-
-        if (!std.ascii.endsWithIgnoreCase(request_line, "http/1.1")) {
-            return error.InvalidProtocol;
-        }
-
-        // we need to extract the sec-websocket-key value
-        var key: []const u8 = "";
-
-        // we need to make sure that we got all the necessary headers + values
-        var required_headers: u8 = 0;
-
-        // can't std.mem.split because it forces the iterated value to be const
-        // (we could @constCast...)
-
-        var buf = request[request_line_end + 2 ..];
-
-        while (buf.len > 4) {
-            const index = std.mem.indexOfScalar(u8, buf, '\r') orelse unreachable;
-            const separator = std.mem.indexOfScalar(u8, buf[0..index], ':') orelse return error.InvalidRequest;
-
-            const name = std.mem.trim(u8, toLower(buf[0..separator]), &std.ascii.whitespace);
-            const value = std.mem.trim(u8, buf[(separator + 1)..index], &std.ascii.whitespace);
-
-            if (std.mem.eql(u8, name, "upgrade")) {
-                if (!std.ascii.eqlIgnoreCase("websocket", value)) {
-                    return error.InvalidUpgradeHeader;
-                }
-                required_headers |= 1;
-            } else if (std.mem.eql(u8, name, "sec-websocket-version")) {
-                if (value.len != 2 or value[0] != '1' or value[1] != '3') {
-                    return error.InvalidVersionHeader;
-                }
-                required_headers |= 2;
-            } else if (std.mem.eql(u8, name, "connection")) {
-                // find if connection header has upgrade in it, example header:
-                // Connection: keep-alive, Upgrade
-                if (std.ascii.indexOfIgnoreCase(value, "upgrade") == null) {
-                    return error.InvalidConnectionHeader;
-                }
-                required_headers |= 4;
-            } else if (std.mem.eql(u8, name, "sec-websocket-key")) {
-                key = value;
-                required_headers |= 8;
-            }
-
-            const next = index + 2;
-            buf = buf[next..];
-        }
-
-        if (required_headers != 15) {
-            return error.MissingHeaders;
-        }
-
-        // our caller has already made sure this request ended in \r\n\r\n
-        // so it isn't something we need to check again
-
-        const allocator = self.send_arena.allocator();
-
-        const response = blk: {
-            // Response to an ugprade request is always this, with
-            // the Sec-Websocket-Accept value a spacial sha1 hash of the
-            // request "sec-websocket-version" and a magic value.
-
-            const template =
-                "HTTP/1.1 101 Switching Protocols\r\n" ++
-                "Upgrade: websocket\r\n" ++
-                "Connection: upgrade\r\n" ++
-                "Sec-Websocket-Accept: 0000000000000000000000000000\r\n\r\n";
-
-            // The response will be sent via the IO Loop and thus has to have its
-            // own lifetime.
-            const res = try allocator.dupe(u8, template);
-
-            // magic response
-            const key_pos = res.len - 32;
-            var h: [20]u8 = undefined;
-            var hasher = std.crypto.hash.Sha1.init(.{});
-            hasher.update(key);
-            // websocket spec always used this value
-            hasher.update("258EAFA5-E914-47DA-95CA-C5AB0DC85B11");
-            hasher.final(&h);
-
-            _ = std.base64.standard.Encoder.encode(res[key_pos .. key_pos + 28], h[0..]);
-
-            break :blk res;
-        };
-
+        try self.ws.upgrade(request);
         self.mode = .{ .cdp = try CDP.init(self.app, self.http, self) };
-        return self.send(response);
     }
 
     fn writeHTTPErrorResponse(self: *Client, comptime status: u16, comptime body: []const u8) void {
-        const response = std.fmt.comptimePrint(
-            "HTTP/1.1 {d} \r\nConnection: Close\r\nContent-Length: {d}\r\n\r\n{s}",
-            .{ status, body.len, body },
-        );
-
-        // we're going to close this connection anyways, swallowing any
-        // error seems safe
-        self.send(response) catch {};
+        self.ws.sendHttpError(status, body);
     }
 
     fn processWebsocketMessage(self: *Client, cdp: *CDP) !bool {
-        var reader = &self.reader;
-        while (true) {
-            const msg = reader.next() catch |err| {
-                switch (err) {
-                    error.TooLarge => self.send(&CLOSE_TOO_BIG) catch {},
-                    error.NotMasked => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.ReservedFlags => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.InvalidMessageType => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.ControlTooLarge => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.InvalidContinuation => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.NestedFragementation => self.send(&CLOSE_PROTOCOL_ERROR) catch {},
-                    error.OutOfMemory => {}, // don't borther trying to send an error in this case
-                }
-                return err;
-            } orelse break;
-
-            switch (msg.type) {
-                .pong => {},
-                .ping => try self.sendPong(msg.data),
-                .close => {
-                    self.send(&CLOSE_NORMAL) catch {};
-                    return false;
-                },
-                .text, .binary => if (cdp.handleMessage(msg.data) == false) {
-                    return false;
-                },
-            }
-            if (msg.cleanup_fragment) {
-                reader.cleanup();
-            }
-        }
-
-        // We might have read part of the next message. Our reader potentially
-        // has to move data around in its buffer to make space.
-        reader.compact();
-        return true;
+        return self.ws.processMessages(cdp);
     }
 
-    fn sendPong(self: *Client, data: []const u8) !void {
-        if (data.len == 0) {
-            return self.send(&EMPTY_PONG);
-        }
-        var header_buf: [10]u8 = undefined;
-        const header = websocketHeader(&header_buf, .pong, data.len);
-
-        const allocator = self.send_arena.allocator();
-        var framed = try allocator.alloc(u8, header.len + data.len);
-        @memcpy(framed[0..header.len], header);
-        @memcpy(framed[header.len..], data);
-        return self.send(framed);
+    pub fn sendAllocator(self: *Client) Allocator {
+        return self.ws.send_arena.allocator();
     }
 
-    // called by CDP
-    // Websocket frames have a variable length header. For server-client,
-    // it could be anywhere from 2 to 10 bytes. Our IO.Loop doesn't have
-    // writev, so we need to get creative. We'll JSON serialize to a
-    // buffer, where the first 10 bytes are reserved. We can then backfill
-    // the header and send the slice.
     pub fn sendJSON(self: *Client, message: anytype, opts: std.json.Stringify.Options) !void {
-        const allocator = self.send_arena.allocator();
-
-        var aw = try std.Io.Writer.Allocating.initCapacity(allocator, 512);
-
-        // reserve space for the maximum possible header
-        try aw.writer.writeAll(&.{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 });
-        try std.json.Stringify.value(message, opts, &aw.writer);
-        const framed = fillWebsocketHeader(aw.toArrayList());
-        return self.send(framed);
+        return self.ws.sendJSON(message, opts);
     }
 
-    pub fn sendJSONRaw(
-        self: *Client,
-        buf: std.ArrayList(u8),
-    ) !void {
-        // Dangerous API!. We assume the caller has reserved the first 10
-        // bytes in `buf`.
-        const framed = fillWebsocketHeader(buf);
-        return self.send(framed);
-    }
-
-    fn send(self: *Client, data: []const u8) !void {
-        var pos: usize = 0;
-        var changed_to_blocking: bool = false;
-        defer _ = self.send_arena.reset(.{ .retain_with_limit = 1024 * 32 });
-
-        defer if (changed_to_blocking) {
-            // We had to change our socket to blocking me to get our write out
-            // We need to change it back to non-blocking.
-            _ = posix.fcntl(self.socket, posix.F.SETFL, self.socket_flags) catch |err| {
-                log.err(.app, "CDP restore nonblocking", .{ .err = err });
-            };
-        };
-
-        LOOP: while (pos < data.len) {
-            const written = posix.write(self.socket, data[pos..]) catch |err| switch (err) {
-                error.WouldBlock => {
-                    // self.socket is nonblocking, because we don't want to block
-                    // reads. But our life is a lot easier if we block writes,
-                    // largely, because we don't have to maintain a queue of pending
-                    // writes (which would each need their own allocations). So
-                    // if we get a WouldBlock error, we'll switch the socket to
-                    // blocking and switch it back to non-blocking after the write
-                    // is complete. Doesn't seem particularly efficiently, but
-                    // this should virtually never happen.
-                    lp.assert(changed_to_blocking == false, "Client.double block", .{});
-                    changed_to_blocking = true;
-                    _ = try posix.fcntl(self.socket, posix.F.SETFL, self.socket_flags & ~@as(u32, @bitCast(posix.O{ .NONBLOCK = true })));
-                    continue :LOOP;
-                },
-                else => return err,
-            };
-
-            if (written == 0) {
-                return error.Closed;
-            }
-            pos += written;
-        }
+    pub fn sendJSONRaw(self: *Client, buf: std.ArrayList(u8)) !void {
+        return self.ws.sendJSONRaw(buf);
     }
 };
 
-// WebSocket message reader. Given websocket message, acts as an iterator that
-// can return zero or more Messages. When next returns null, any incomplete
-// message will remain in reader.data
-fn Reader(comptime EXPECT_MASK: bool) type {
-    return struct {
-        allocator: Allocator,
-
-        // position in buf of the start of the next message
-        pos: usize = 0,
-
-        // position in buf up until where we have valid data
-        // (any new reads must be placed after this)
-        len: usize = 0,
-
-        // we add 140 to allow 1 control message (ping/pong/close) to be
-        // fragmented into a normal message.
-        buf: []u8,
-
-        fragments: ?Fragments = null,
-
-        const Self = @This();
-
-        fn init(allocator: Allocator) !Self {
-            const buf = try allocator.alloc(u8, 16 * 1024);
-            return .{
-                .buf = buf,
-                .allocator = allocator,
-            };
-        }
-
-        fn deinit(self: *Self) void {
-            self.cleanup();
-            self.allocator.free(self.buf);
-        }
-
-        fn cleanup(self: *Self) void {
-            if (self.fragments) |*f| {
-                f.message.deinit(self.allocator);
-                self.fragments = null;
-            }
-        }
-
-        fn readBuf(self: *Self) []u8 {
-            // We might have read a partial http or websocket message.
-            // Subsequent reads must read from where we left off.
-            return self.buf[self.len..];
-        }
-
-        fn next(self: *Self) !?Message {
-            LOOP: while (true) {
-                var buf = self.buf[self.pos..self.len];
-
-                const length_of_len, const message_len = extractLengths(buf) orelse {
-                    // we don't have enough bytes
-                    return null;
-                };
-
-                const byte1 = buf[0];
-
-                if (byte1 & 112 != 0) {
-                    return error.ReservedFlags;
-                }
-
-                if (comptime EXPECT_MASK) {
-                    if (buf[1] & 128 != 128) {
-                        // client -> server messages _must_ be masked
-                        return error.NotMasked;
-                    }
-                } else if (buf[1] & 128 != 0) {
-                    // server -> client are never masked
-                    return error.Masked;
-                }
-
-                var is_control = false;
-                var is_continuation = false;
-                var message_type: Message.Type = undefined;
-                switch (byte1 & 15) {
-                    0 => is_continuation = true,
-                    1 => message_type = .text,
-                    2 => message_type = .binary,
-                    8 => {
-                        is_control = true;
-                        message_type = .close;
-                    },
-                    9 => {
-                        is_control = true;
-                        message_type = .ping;
-                    },
-                    10 => {
-                        is_control = true;
-                        message_type = .pong;
-                    },
-                    else => return error.InvalidMessageType,
-                }
-
-                if (is_control) {
-                    if (message_len > 125) {
-                        return error.ControlTooLarge;
-                    }
-                } else if (message_len > Config.CDP_MAX_MESSAGE_SIZE) {
-                    return error.TooLarge;
-                } else if (message_len > self.buf.len) {
-                    const len = self.buf.len;
-                    self.buf = try growBuffer(self.allocator, self.buf, message_len);
-                    buf = self.buf[0..len];
-                    // we need more data
-                    return null;
-                } else if (buf.len < message_len) {
-                    // we need more data
-                    return null;
-                }
-
-                // prefix + length_of_len + mask
-                const header_len = 2 + length_of_len + if (comptime EXPECT_MASK) 4 else 0;
-
-                const payload = buf[header_len..message_len];
-                if (comptime EXPECT_MASK) {
-                    mask(buf[header_len - 4 .. header_len], payload);
-                }
-
-                // whatever happens after this, we know where the next message starts
-                self.pos += message_len;
-
-                const fin = byte1 & 128 == 128;
-
-                if (is_continuation) {
-                    const fragments = &(self.fragments orelse return error.InvalidContinuation);
-                    if (fragments.message.items.len + message_len > Config.CDP_MAX_MESSAGE_SIZE) {
-                        return error.TooLarge;
-                    }
-
-                    try fragments.message.appendSlice(self.allocator, payload);
-
-                    if (fin == false) {
-                        // maybe we have more parts of the message waiting
-                        continue :LOOP;
-                    }
-
-                    // this continuation is done!
-                    return .{
-                        .type = fragments.type,
-                        .data = fragments.message.items,
-                        .cleanup_fragment = true,
-                    };
-                }
-
-                const can_be_fragmented = message_type == .text or message_type == .binary;
-                if (self.fragments != null and can_be_fragmented) {
-                    // if this isn't a continuation, then we can't have fragments
-                    return error.NestedFragementation;
-                }
-
-                if (fin == false) {
-                    if (can_be_fragmented == false) {
-                        return error.InvalidContinuation;
-                    }
-
-                    // not continuation, and not fin. It has to be the first message
-                    // in a fragmented message.
-                    var fragments = Fragments{ .message = .{}, .type = message_type };
-                    try fragments.message.appendSlice(self.allocator, payload);
-                    self.fragments = fragments;
-                    continue :LOOP;
-                }
-
-                return .{
-                    .data = payload,
-                    .type = message_type,
-                    .cleanup_fragment = false,
-                };
-            }
-        }
-
-        fn extractLengths(buf: []const u8) ?struct { usize, usize } {
-            if (buf.len < 2) {
-                return null;
-            }
-
-            const length_of_len: usize = switch (buf[1] & 127) {
-                126 => 2,
-                127 => 8,
-                else => 0,
-            };
-
-            if (buf.len < length_of_len + 2) {
-                // we definitely don't have enough buf yet
-                return null;
-            }
-
-            const message_len = switch (length_of_len) {
-                2 => @as(u16, @intCast(buf[3])) | @as(u16, @intCast(buf[2])) << 8,
-                8 => @as(u64, @intCast(buf[9])) | @as(u64, @intCast(buf[8])) << 8 | @as(u64, @intCast(buf[7])) << 16 | @as(u64, @intCast(buf[6])) << 24 | @as(u64, @intCast(buf[5])) << 32 | @as(u64, @intCast(buf[4])) << 40 | @as(u64, @intCast(buf[3])) << 48 | @as(u64, @intCast(buf[2])) << 56,
-                else => buf[1] & 127,
-            } + length_of_len + 2 + if (comptime EXPECT_MASK) 4 else 0; // +2 for header prefix, +4 for mask;
-
-            return .{ length_of_len, message_len };
-        }
-
-        // This is called after we've processed complete websocket messages (this
-        // only applies to websocket messages).
-        // There are three cases:
-        // 1 - We don't have any incomplete data (for a subsequent message) in buf.
-        //     This is the easier to handle, we can set pos & len to 0.
-        // 2 - We have part of the next message, but we know it'll fit in the
-        //     remaining buf. We don't need to do anything
-        // 3 - We have part of the next message, but either it won't fight into the
-        //     remaining buffer, or we don't know (because we don't have enough
-        //     of the header to tell the length). We need to "compact" the buffer
-        fn compact(self: *Self) void {
-            const pos = self.pos;
-            const len = self.len;
-
-            lp.assert(pos <= len, "Client.Reader.compact precondition", .{ .pos = pos, .len = len });
-
-            // how many (if any) partial bytes do we have
-            const partial_bytes = len - pos;
-
-            if (partial_bytes == 0) {
-                // We have no partial bytes. Setting these to 0 ensures that we
-                // get the best utilization of our buffer
-                self.pos = 0;
-                self.len = 0;
-                return;
-            }
-
-            const partial = self.buf[pos..len];
-
-            // If we have enough bytes of the next message to tell its length
-            // we'll be able to figure out whether we need to do anything or not.
-            if (extractLengths(partial)) |length_meta| {
-                const next_message_len = length_meta.@"1";
-                // if this isn't true, then we have a full message and it
-                // should have been processed.
-                lp.assert(pos <= len, "Client.Reader.compact postcondition", .{ .next_len = next_message_len, .partial = partial_bytes });
-
-                const missing_bytes = next_message_len - partial_bytes;
-
-                const free_space = self.buf.len - len;
-                if (missing_bytes < free_space) {
-                    // we have enough space in our buffer, as is,
-                    return;
-                }
-            }
-
-            // We're here because we either don't have enough bytes of the next
-            // message, or we know that it won't fit in our buffer as-is.
-            std.mem.copyForwards(u8, self.buf, partial);
-            self.pos = 0;
-            self.len = partial_bytes;
-        }
-    };
-}
-
-fn growBuffer(allocator: Allocator, buf: []u8, required_capacity: usize) ![]u8 {
-    // from std.ArrayList
-    var new_capacity = buf.len;
-    while (true) {
-        new_capacity +|= new_capacity / 2 + 8;
-        if (new_capacity >= required_capacity) break;
-    }
-
-    log.debug(.app, "CDP buffer growth", .{ .from = buf.len, .to = new_capacity });
-
-    if (allocator.resize(buf, new_capacity)) {
-        return buf.ptr[0..new_capacity];
-    }
-    const new_buffer = try allocator.alloc(u8, new_capacity);
-    @memcpy(new_buffer[0..buf.len], buf);
-    allocator.free(buf);
-    return new_buffer;
-}
-
-const Fragments = struct {
-    type: Message.Type,
-    message: std.ArrayList(u8),
-};
-
-const Message = struct {
-    type: Type,
-    data: []const u8,
-    cleanup_fragment: bool,
-
-    const Type = enum {
-        text,
-        binary,
-        close,
-        ping,
-        pong,
-    };
-};
-
-// These are the only websocket types that we're currently sending
-const OpCode = enum(u8) {
-    text = 128 | 1,
-    close = 128 | 8,
-    pong = 128 | 10,
-};
-
-fn fillWebsocketHeader(buf: std.ArrayList(u8)) []const u8 {
-    // can't use buf[0..10] here, because the header length
-    // is variable. If it's just 2 bytes, for example, we need the
-    // framed message to be:
-    //     h1, h2, data
-    // If we use buf[0..10], we'd get:
-    //    h1, h2, 0, 0, 0, 0, 0, 0, 0, 0, data
-
-    var header_buf: [10]u8 = undefined;
-
-    // -10 because we reserved 10 bytes for the header above
-    const header = websocketHeader(&header_buf, .text, buf.items.len - 10);
-    const start = 10 - header.len;
-
-    const message = buf.items;
-    @memcpy(message[start..10], header);
-    return message[start..];
-}
-
-// makes the assumption that our caller reserved the first
-// 10 bytes for the header
-fn websocketHeader(buf: []u8, op_code: OpCode, payload_len: usize) []const u8 {
-    lp.assert(buf.len == 10, "Websocket.Header", .{ .len = buf.len });
-
-    const len = payload_len;
-    buf[0] = 128 | @intFromEnum(op_code); // fin | opcode
-
-    if (len <= 125) {
-        buf[1] = @intCast(len);
-        return buf[0..2];
-    }
-
-    if (len < 65536) {
-        buf[1] = 126;
-        buf[2] = @intCast((len >> 8) & 0xFF);
-        buf[3] = @intCast(len & 0xFF);
-        return buf[0..4];
-    }
-
-    buf[1] = 127;
-    buf[2] = 0;
-    buf[3] = 0;
-    buf[4] = 0;
-    buf[5] = 0;
-    buf[6] = @intCast((len >> 24) & 0xFF);
-    buf[7] = @intCast((len >> 16) & 0xFF);
-    buf[8] = @intCast((len >> 8) & 0xFF);
-    buf[9] = @intCast(len & 0xFF);
-    return buf[0..10];
-}
-
 // Utils
 // --------
 
@@ -1139,48 +584,6 @@ fn buildJSONVersionResponse(
 
 pub const timestamp = @import("datetime.zig").timestamp;
 
-// In-place string lowercase
-fn toLower(str: []u8) []u8 {
-    for (str, 0..) |c, i| {
-        str[i] = std.ascii.toLower(c);
-    }
-    return str;
-}
-
-// Zig is in a weird backend transition right now. Need to determine if
-// SIMD is even available.
-const backend_supports_vectors = switch (builtin.zig_backend) {
-    .stage2_llvm, .stage2_c => true,
-    else => false,
-};
-
-// Websocket messages from client->server are masked using a 4 byte XOR mask
-fn mask(m: []const u8, payload: []u8) void {
-    var data = payload;
-
-    if (!comptime backend_supports_vectors) return simpleMask(m, data);
-
-    const vector_size = std.simd.suggestVectorLength(u8) orelse @sizeOf(usize);
-    if (data.len >= vector_size) {
-        const mask_vector = std.simd.repeat(vector_size, @as(@Vector(4, u8), m[0..4].*));
-        while (data.len >= vector_size) {
-            const slice = data[0..vector_size];
-            const masked_data_slice: @Vector(vector_size, u8) = slice.*;
-            slice.* = masked_data_slice ^ mask_vector;
-            data = data[vector_size..];
-        }
-    }
-    simpleMask(m, data);
-}
-
-// Used when SIMD isn't available, or for any remaining part of the message
-// which is too small to effectively use SIMD.
-fn simpleMask(m: []const u8, payload: []u8) void {
-    for (payload, 0..) |b, i| {
-        payload[i] = b ^ m[i & 3];
-    }
-}
-
 const testing = std.testing;
 test "server: buildJSONVersionResponse" {
     const address = try net.Address.parseIp4("127.0.0.1", 9001);
@@ -1391,22 +794,6 @@ test "Client: close message" {
     );
 }
 
-test "server: mask" {
-    var buf: [4000]u8 = undefined;
-    const messages = [_][]const u8{ "1234", "1234" ** 99, "1234" ** 999 };
-    for (messages) |message| {
-        // we need the message to be mutable since mask operates in-place
-        const payload = buf[0..message.len];
-        @memcpy(payload, message);
-
-        mask(&.{ 1, 2, 200, 240 }, payload);
-        try testing.expectEqual(false, std.mem.eql(u8, payload, message));
-
-        mask(&.{ 1, 2, 200, 240 }, payload);
-        try testing.expectEqual(true, std.mem.eql(u8, payload, message));
-    }
-}
-
 test "server: 404" {
     var c = try createTestClient();
     defer c.deinit();
@@ -1542,7 +929,7 @@ fn createTestClient() !TestClient {
 const TestClient = struct {
     stream: std.net.Stream,
     buf: [1024]u8 = undefined,
-    reader: Reader(false),
+    reader: Net.Reader(false),
 
     fn deinit(self: *TestClient) void {
         self.stream.close();
@@ -1609,7 +996,7 @@ const TestClient = struct {
             "Sec-Websocket-Accept: flzHu2DevQ2dSCSVqKSii5e9C2o=\r\n\r\n", res);
     }
 
-    fn readWebsocketMessage(self: *TestClient) !?Message {
+    fn readWebsocketMessage(self: *TestClient) !?Net.Message {
         while (true) {
             const n = try self.stream.read(self.reader.readBuf());
             if (n == 0) {

src/TestHTTPServer.zig

@@ -17,6 +17,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const URL = @import("browser/URL.zig");
 
 const TestHTTPServer = @This();
 
@@ -97,7 +98,10 @@ fn handleConnection(self: *TestHTTPServer, conn: std.net.Server.Connection) !voi
 }
 
 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) {
+    var url_buf: [1024]u8 = undefined;
+    var fba = std.heap.FixedBufferAllocator.init(&url_buf);
+    const unescaped_file_path = try URL.unescape(fba.allocator(), file_path);
+    var file = std.fs.cwd().openFile(unescaped_file_path, .{}) catch |err| switch (err) {
         error.FileNotFound => return req.respond("server error", .{ .status = .not_found }),
         else => return err,
     };

src/browser/Browser.zig

@@ -87,19 +87,29 @@ pub fn closeSession(self: *Browser) void {
     }
 }
 
-pub fn runMicrotasks(self: *const Browser) void {
+pub fn runMicrotasks(self: *Browser) void {
     self.env.runMicrotasks();
 }
 
 pub fn runMacrotasks(self: *Browser) !?u64 {
-    return try self.env.runMacrotasks();
+    const env = &self.env;
+
+    const time_to_next = try self.env.runMacrotasks();
+    env.pumpMessageLoop();
+
+    // either of the above could have queued more microtasks
+    env.runMicrotasks();
+
+    return time_to_next;
 }
 
-pub fn runMessageLoop(self: *const Browser) void {
-    while (self.env.pumpMessageLoop()) {
-        if (comptime IS_DEBUG) {
-            log.debug(.browser, "pumpMessageLoop", .{});
-        }
-    }
+pub fn hasBackgroundTasks(self: *Browser) bool {
+    return self.env.hasBackgroundTasks();
+}
+pub fn waitForBackgroundTasks(self: *Browser) void {
+    self.env.waitForBackgroundTasks();
+}
+
+pub fn runIdleTasks(self: *const Browser) void {
     self.env.runIdleTasks();
 }

src/browser/EventManager.zig

@@ -56,7 +56,12 @@ pub const EventManager = @This();
 
 page: *Page,
 arena: Allocator,
+// Used as an optimization in Page._documentIsComplete. If we know there are no
+// 'load' listeners in the document, we can skip dispatching the per-resource
+// 'load' event (e.g. amazon product page has no listener and ~350 resources)
+has_dom_load_listener: bool,
 listener_pool: std.heap.MemoryPool(Listener),
+ignore_list: std.ArrayList(*Listener),
 list_pool: std.heap.MemoryPool(std.DoublyLinkedList),
 lookup: std.HashMapUnmanaged(
     EventKey,
@@ -72,10 +77,12 @@ pub fn init(arena: Allocator, page: *Page) EventManager {
         .page = page,
         .lookup = .{},
         .arena = arena,
+        .ignore_list = .{},
         .list_pool = .init(arena),
         .listener_pool = .init(arena),
         .dispatch_depth = 0,
         .deferred_removals = .{},
+        .has_dom_load_listener = false,
     };
 }
 
@@ -106,6 +113,10 @@ pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, call
     // Allocate the type string we'll use in both listener and key
     const type_string = try String.init(self.arena, typ, .{});
 
+    if (type_string.eql(comptime .wrap("load")) and target._type == .node) {
+        self.has_dom_load_listener = true;
+    }
+
     const gop = try self.lookup.getOrPut(self.arena, .{
         .type_string = type_string,
         .event_target = @intFromPtr(target),
@@ -146,6 +157,11 @@ pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, call
     };
     // append the listener to the list of listeners for this target
     gop.value_ptr.*.append(&listener.node);
+
+    // Track load listeners for script execution ignore list
+    if (type_string.eql(comptime .wrap("load"))) {
+        try self.ignore_list.append(self.arena, listener);
+    }
 }
 
 pub fn remove(self: *EventManager, target: *EventTarget, typ: []const u8, callback: Callback, use_capture: bool) void {
@@ -158,6 +174,10 @@ pub fn remove(self: *EventManager, target: *EventTarget, typ: []const u8, callba
     }
 }
 
+pub fn clearIgnoreList(self: *EventManager) void {
+    self.ignore_list.clearRetainingCapacity();
+}
+
 // Dispatching can be recursive from the compiler's point of view, so we need to
 // give it an explicit error set so that other parts of the code can use and
 // inferred error.
@@ -169,42 +189,31 @@ const DispatchError = error{
     ExecutionError,
     JsException,
 };
+
+pub const DispatchOpts = struct {
+    // A "load" event triggered by a script (in ScriptManager) should not trigger
+    // a "load" listener added within that script. Therefore, any "load" listener
+    // that we add go into an ignore list until after the script finishes executing.
+    // The ignore list is only checked when apply_ignore  == true, which is only
+    // set by the ScriptManager when raising the script's "load" event.
+    apply_ignore: bool = false,
+};
+
 pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) DispatchError!void {
+    return self.dispatchOpts(target, event, .{});
+}
+
+pub fn dispatchOpts(self: *EventManager, target: *EventTarget, event: *Event, comptime opts: DispatchOpts) DispatchError!void {
+    event.acquireRef();
+    defer event.deinit(false, self.page);
+
     if (comptime IS_DEBUG) {
         log.debug(.event, "eventManager.dispatch", .{ .type = event._type_string.str(), .bubbles = event._bubbles });
     }
 
-    event._target = target;
-    event._dispatch_target = target; // Store original target for composedPath()
-    var was_handled = false;
-
-    defer if (was_handled) {
-        var ls: js.Local.Scope = undefined;
-        self.page.js.localScope(&ls);
-        defer ls.deinit();
-        ls.local.runMicrotasks();
-    };
-
     switch (target._type) {
-        .node => |node| try self.dispatchNode(node, event, &was_handled),
-        .xhr,
-        .window,
-        .abort_signal,
-        .media_query_list,
-        .message_port,
-        .text_track_cue,
-        .navigation,
-        .screen,
-        .screen_orientation,
-        .visual_viewport,
-        .generic,
-        => {
-            const list = self.lookup.get(.{
-                .event_target = @intFromPtr(target),
-                .type_string = event._type_string,
-            }) orelse return;
-            try self.dispatchAll(list, target, event, &was_handled);
-        },
+        .node => |node| try self.dispatchNode(node, event, opts),
+        else => try self.dispatchDirect(target, event, null, .{ .context = "dispatch" }),
     }
 }
 
@@ -213,13 +222,22 @@ pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) Dispat
 // 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 {
+const DispatchDirectOptions = struct {
     context: []const u8,
     inject_target: bool = true,
 };
-pub fn dispatchWithFunction(self: *EventManager, target: *EventTarget, event: *Event, function_: ?js.Function, comptime opts: DispatchWithFunctionOptions) !void {
+
+// Direct dispatch for non-DOM targets (Window, XHR, AbortSignal) or DOM nodes with
+// property handlers. No propagation - just calls the handler and registered listeners.
+// Handler can be: null, ?js.Function.Global, ?js.Function.Temp, or js.Function
+pub fn dispatchDirect(self: *EventManager, target: *EventTarget, event: *Event, handler: anytype, comptime opts: DispatchDirectOptions) !void {
+    const page = self.page;
+
+    event.acquireRef();
+    defer event.deinit(false, page);
+
     if (comptime IS_DEBUG) {
-        log.debug(.event, "dispatchWithFunction", .{ .type = event._type_string.str(), .context = opts.context, .has_function = function_ != null });
+        log.debug(.event, "dispatchDirect", .{ .type = event._type_string, .context = opts.context });
     }
 
     if (comptime opts.inject_target) {
@@ -228,14 +246,15 @@ pub fn dispatchWithFunction(self: *EventManager, target: *EventTarget, event: *E
     }
 
     var was_dispatched = false;
-    defer if (was_dispatched) {
-        var ls: js.Local.Scope = undefined;
-        self.page.js.localScope(&ls);
-        defer ls.deinit();
-        ls.local.runMicrotasks();
-    };
 
-    if (function_) |func| {
+    var ls: js.Local.Scope = undefined;
+    page.js.localScope(&ls);
+    defer {
+        ls.local.runMicrotasks();
+        ls.deinit();
+    }
+
+    if (getFunction(handler, &ls.local)) |func| {
         event._current_target = target;
         if (func.callWithThis(void, target, .{event})) {
             was_dispatched = true;
@@ -245,23 +264,139 @@ pub fn dispatchWithFunction(self: *EventManager, target: *EventTarget, event: *E
         }
     }
 
+    // listeners reigstered via addEventListener
     const list = self.lookup.get(.{
         .event_target = @intFromPtr(target),
         .type_string = event._type_string,
     }) orelse return;
-    try self.dispatchAll(list, target, event, &was_dispatched);
+
+    // This is a slightly simplified version of what you'll find in dispatchPhase
+    // It is simpler because, for direct dispatching, we know there's no ancestors
+    // and only the single target phase.
+
+    // Track dispatch depth for deferred removal
+    self.dispatch_depth += 1;
+    defer {
+        const dispatch_depth = self.dispatch_depth;
+        // Only destroy deferred listeners when we exit the outermost dispatch
+        if (dispatch_depth == 1) {
+            for (self.deferred_removals.items) |removal| {
+                removal.list.remove(&removal.listener.node);
+                self.listener_pool.destroy(removal.listener);
+            }
+            self.deferred_removals.clearRetainingCapacity();
+        } else {
+            self.dispatch_depth = dispatch_depth - 1;
+        }
+    }
+
+    // Use the last listener in the list as sentinel - listeners added during dispatch will be after it
+    const last_node = list.last orelse return;
+    const last_listener: *Listener = @alignCast(@fieldParentPtr("node", last_node));
+
+    // Iterate through the list, stopping after we've encountered the last_listener
+    var node = list.first;
+    var is_done = false;
+    while (node) |n| {
+        if (is_done) {
+            break;
+        }
+
+        const listener: *Listener = @alignCast(@fieldParentPtr("node", n));
+        is_done = (listener == last_listener);
+        node = n.next;
+
+        // Skip removed listeners
+        if (listener.removed) {
+            continue;
+        }
+
+        // If the listener has an aborted signal, remove it and skip
+        if (listener.signal) |signal| {
+            if (signal.getAborted()) {
+                self.removeListener(list, listener);
+                continue;
+            }
+        }
+
+        // Remove "once" listeners BEFORE calling them so nested dispatches don't see them
+        if (listener.once) {
+            self.removeListener(list, listener);
+        }
+
+        was_dispatched = true;
+        event._current_target = target;
+
+        switch (listener.function) {
+            .value => |value| try ls.toLocal(value).callWithThis(void, target, .{event}),
+            .string => |string| {
+                const str = try page.call_arena.dupeZ(u8, string.str());
+                try ls.local.eval(str, null);
+            },
+            .object => |obj_global| {
+                const obj = ls.toLocal(obj_global);
+                if (try obj.getFunction("handleEvent")) |handleEvent| {
+                    try handleEvent.callWithThis(void, obj, .{event});
+                }
+            },
+        }
+
+        if (event._stop_immediate_propagation) {
+            return;
+        }
+    }
 }
 
-fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled: *bool) !void {
+fn getFunction(handler: anytype, local: *const js.Local) ?js.Function {
+    const T = @TypeOf(handler);
+    const ti = @typeInfo(T);
+
+    if (ti == .null) {
+        return null;
+    }
+    if (ti == .optional) {
+        return getFunction(handler orelse return null, local);
+    }
+    return switch (T) {
+        js.Function => handler,
+        js.Function.Temp => local.toLocal(handler),
+        js.Function.Global => local.toLocal(handler),
+        else => @compileError("handler must be null or \\??js.Function(\\.(Temp|Global))?"),
+    };
+}
+
+fn dispatchNode(self: *EventManager, target: *Node, event: *Event, comptime opts: DispatchOpts) !void {
     const ShadowRoot = @import("webapi/ShadowRoot.zig");
 
+    {
+        const et = target.asEventTarget();
+        event._target = et;
+        event._dispatch_target = et; // Store original target for composedPath()
+    }
+
     const page = self.page;
+    var was_handled = false;
+
+    // Create a single scope for all event handlers in this dispatch.
+    // This ensures function handles passed to queueMicrotask remain valid
+    // throughout the entire dispatch, preventing crashes when microtasks run.
+    var ls: js.Local.Scope = undefined;
+    page.js.localScope(&ls);
+    defer {
+        if (was_handled) {
+            ls.local.runMicrotasks();
+        }
+        ls.deinit();
+    }
+
     const activation_state = ActivationState.create(event, target, page);
 
     // Defer runs even on early return - ensures event phase is reset
     // and default actions execute (unless prevented)
     defer {
         event._event_phase = .none;
+        event._stop_propagation = false;
+        event._stop_immediate_propagation = false;
         // Handle checkbox/radio activation rollback or commit
         if (activation_state) |state| {
             state.restore(event, page);
@@ -307,11 +442,14 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
         node = n._parent;
     }
 
-    // Even though the window isn't part of the DOM, events always propagate
+    // Even though the window isn't part of the DOM, most events propagate
     // through it in the capture phase (unless we stopped at a shadow boundary)
-    if (path_len < path_buffer.len) {
-        path_buffer[path_len] = page.window.asEventTarget();
-        path_len += 1;
+    // The only explicit exception is "load"
+    if (event._type_string.eql(comptime .wrap("load")) == false) {
+        if (path_len < path_buffer.len) {
+            path_buffer[path_len] = page.window.asEventTarget();
+            path_len += 1;
+        }
     }
 
     const path = path_buffer[0..path_len];
@@ -322,32 +460,27 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     var i: usize = path_len;
     while (i > 1) {
         i -= 1;
+        if (event._stop_propagation) return;
         const current_target = path[i];
         if (self.lookup.get(.{
             .event_target = @intFromPtr(current_target),
             .type_string = event._type_string,
         })) |list| {
-            try self.dispatchPhase(list, current_target, event, was_handled, true);
-            if (event._stop_propagation) {
-                return;
-            }
+            try self.dispatchPhase(list, current_target, event, &was_handled, &ls.local, comptime .init(true, opts));
         }
     }
 
     // Phase 2: At target
+    if (event._stop_propagation) return;
     event._event_phase = .at_target;
     const target_et = target.asEventTarget();
 
     blk: {
         // Get inline handler (e.g., onclick property) for this target
         if (self.getInlineHandler(target_et, event)) |inline_handler| {
-            was_handled.* = true;
+            was_handled = true;
             event._current_target = target_et;
 
-            var ls: js.Local.Scope = undefined;
-            self.page.js.localScope(&ls);
-            defer ls.deinit();
-
             try ls.toLocal(inline_handler).callWithThis(void, target_et, .{event});
 
             if (event._stop_propagation) {
@@ -363,7 +496,7 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
             .type_string = event._type_string,
             .event_target = @intFromPtr(target_et),
         })) |list| {
-            try self.dispatchPhase(list, target_et, event, was_handled, null);
+            try self.dispatchPhase(list, target_et, event, &was_handled, &ls.local, comptime .init(null, opts));
             if (event._stop_propagation) {
                 return;
             }
@@ -375,20 +508,30 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     if (event._bubbles) {
         event._event_phase = .bubbling_phase;
         for (path[1..]) |current_target| {
+            if (event._stop_propagation) break;
             if (self.lookup.get(.{
                 .type_string = event._type_string,
                 .event_target = @intFromPtr(current_target),
             })) |list| {
-                try self.dispatchPhase(list, current_target, event, was_handled, false);
-                if (event._stop_propagation) {
-                    break;
-                }
+                try self.dispatchPhase(list, current_target, event, &was_handled, &ls.local, comptime .init(false, opts));
             }
         }
     }
 }
 
-fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event, was_handled: *bool, comptime capture_only: ?bool) !void {
+const DispatchPhaseOpts = struct {
+    capture_only: ?bool = null,
+    apply_ignore: bool = false,
+
+    fn init(capture_only: ?bool, opts: DispatchOpts) DispatchPhaseOpts {
+        return .{
+            .capture_only = capture_only,
+            .apply_ignore = opts.apply_ignore,
+        };
+    }
+};
+
+fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event, was_handled: *bool, local: *const js.Local, comptime opts: DispatchPhaseOpts) !void {
     const page = self.page;
 
     // Track dispatch depth for deferred removal
@@ -414,7 +557,7 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
     // Iterate through the list, stopping after we've encountered the last_listener
     var node = list.first;
     var is_done = false;
-    while (node) |n| {
+    node_loop: while (node) |n| {
         if (is_done) {
             break;
         }
@@ -424,7 +567,7 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
         node = n.next;
 
         // Skip non-matching listeners
-        if (comptime capture_only) |capture| {
+        if (comptime opts.capture_only) |capture| {
             if (listener.capture != capture) {
                 continue;
             }
@@ -443,6 +586,14 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
             }
         }
 
+        if (comptime opts.apply_ignore) {
+            for (self.ignore_list.items) |ignored| {
+                if (ignored == listener) {
+                    continue :node_loop;
+                }
+            }
+        }
+
         // Remove "once" listeners BEFORE calling them so nested dispatches don't see them
         if (listener.once) {
             self.removeListener(list, listener);
@@ -457,18 +608,14 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
             event._target = getAdjustedTarget(original_target, current_target);
         }
 
-        var ls: js.Local.Scope = undefined;
-        page.js.localScope(&ls);
-        defer ls.deinit();
-
         switch (listener.function) {
-            .value => |value| try ls.toLocal(value).callWithThis(void, current_target, .{event}),
+            .value => |value| try local.toLocal(value).callWithThis(void, current_target, .{event}),
             .string => |string| {
                 const str = try page.call_arena.dupeZ(u8, string.str());
-                try ls.local.eval(str, null);
+                try local.eval(str, null);
             },
             .object => |obj_global| {
-                const obj = ls.toLocal(obj_global);
+                const obj = local.toLocal(obj_global);
                 if (try obj.getFunction("handleEvent")) |handleEvent| {
                     try handleEvent.callWithThis(void, obj, .{event});
                 }
@@ -486,22 +633,20 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
     }
 }
 
-//  Non-Node dispatching (XHR, Window without propagation)
-fn dispatchAll(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event, was_handled: *bool) !void {
-    return self.dispatchPhase(list, current_target, event, was_handled, null);
-}
-
 fn getInlineHandler(self: *EventManager, target: *EventTarget, event: *Event) ?js.Function.Global {
     const global_event_handlers = @import("webapi/global_event_handlers.zig");
     const handler_type = global_event_handlers.fromEventType(event._type_string.str()) orelse return null;
 
     // Look up the inline handler for this target
-    const element = switch (target._type) {
-        .node => |n| n.is(Element) orelse return null,
+    const html_element = switch (target._type) {
+        .node => |n| n.is(Element.Html) orelse return null,
         else => return null,
     };
 
-    return self.page.getAttrListener(element, handler_type);
+    return html_element.getAttributeFunction(handler_type, self.page) catch |err| {
+        log.warn(.event, "inline html callback", .{ .type = handler_type, .err = err });
+        return null;
+    };
 }
 
 fn removeListener(self: *EventManager, list: *std.DoublyLinkedList, listener: *Listener) void {
@@ -682,9 +827,10 @@ const ActivationState = struct {
         }
 
         // Commit: fire input and change events only if state actually changed
+        // and the element is connected to a document (detached elements don't fire).
         // For checkboxes, state always changes. For radios, only if was unchecked.
         const state_changed = (input._input_type == .checkbox) or !self.old_checked;
-        if (state_changed) {
+        if (state_changed and input.asElement().asNode().isConnected()) {
             fireEvent(page, input, "input") catch |err| {
                 log.warn(.event, "input event", .{ .err = err });
             };
@@ -754,7 +900,6 @@ const ActivationState = struct {
             .bubbles = true,
             .cancelable = false,
         }, page);
-        defer if (!event._v8_handoff) event.deinit(false);
 
         const target = input.asElement().asEventTarget();
         try page._event_manager.dispatch(target, event);

src/browser/Factory.zig

@@ -42,12 +42,96 @@ const Allocator = std.mem.Allocator;
 const IS_DEBUG = builtin.mode == .Debug;
 const assert = std.debug.assert;
 
+// Shared across all frames of a Page.
 const Factory = @This();
 
-_page: *Page,
 _arena: Allocator,
 _slab: SlabAllocator,
 
+pub fn init(arena: Allocator) !*Factory {
+    const self = try arena.create(Factory);
+    self.* = .{
+        ._arena = arena,
+        ._slab = SlabAllocator.init(arena, 128),
+    };
+    return self;
+}
+
+// this is a root object
+pub fn eventTarget(self: *Factory, child: anytype) !*@TypeOf(child) {
+    return self.eventTargetWithAllocator(self._slab.allocator(), child);
+}
+
+pub fn eventTargetWithAllocator(_: *const Factory, allocator: Allocator, child: anytype) !*@TypeOf(child) {
+    const chain = try PrototypeChain(
+        &.{ EventTarget, @TypeOf(child) },
+    ).allocate(allocator);
+
+    const event_ptr = chain.get(0);
+    event_ptr.* = .{
+        ._type = unionInit(EventTarget.Type, chain.get(1)),
+    };
+    chain.setLeaf(1, child);
+
+    return chain.get(1);
+}
+
+pub fn standaloneEventTarget(self: *Factory, child: anytype) !*EventTarget {
+    const allocator = self._slab.allocator();
+    const et = try allocator.create(EventTarget);
+    et.* = .{ ._type = unionInit(EventTarget.Type, child) };
+    return et;
+}
+
+// this is a root object
+pub fn event(_: *const Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
+    const chain = try PrototypeChain(
+        &.{ Event, @TypeOf(child) },
+    ).allocate(arena);
+
+    // Special case: Event has a _type_string field, so we need manual setup
+    const event_ptr = chain.get(0);
+    event_ptr.* = try eventInit(arena, typ, chain.get(1));
+    chain.setLeaf(1, child);
+
+    return chain.get(1);
+}
+
+pub fn uiEvent(_: *const Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
+    const chain = try PrototypeChain(
+        &.{ Event, UIEvent, @TypeOf(child) },
+    ).allocate(arena);
+
+    // Special case: Event has a _type_string field, so we need manual setup
+    const event_ptr = chain.get(0);
+    event_ptr.* = try eventInit(arena, typ, chain.get(1));
+    chain.setMiddle(1, UIEvent.Type);
+    chain.setLeaf(2, child);
+
+    return chain.get(2);
+}
+
+pub fn mouseEvent(_: *const Factory, arena: Allocator, typ: String, mouse: MouseEvent, child: anytype) !*@TypeOf(child) {
+    const chain = try PrototypeChain(
+        &.{ Event, UIEvent, MouseEvent, @TypeOf(child) },
+    ).allocate(arena);
+
+    // Special case: Event has a _type_string field, so we need manual setup
+    const event_ptr = chain.get(0);
+    event_ptr.* = try eventInit(arena, typ, chain.get(1));
+    chain.setMiddle(1, UIEvent.Type);
+
+    // Set MouseEvent with all its fields
+    const mouse_ptr = chain.get(2);
+    mouse_ptr.* = mouse;
+    mouse_ptr._proto = chain.get(1);
+    mouse_ptr._type = unionInit(MouseEvent.Type, chain.get(3));
+
+    chain.setLeaf(3, child);
+
+    return chain.get(3);
+}
+
 fn PrototypeChain(comptime types: []const type) type {
     return struct {
         const Self = @This();
@@ -151,94 +235,14 @@ fn AutoPrototypeChain(comptime types: []const type) type {
     };
 }
 
-pub fn init(arena: Allocator, page: *Page) Factory {
-    return .{
-        ._page = page,
-        ._arena = arena,
-        ._slab = SlabAllocator.init(arena, 128),
-    };
-}
-
-// this is a root object
-pub fn eventTarget(self: *Factory, child: anytype) !*@TypeOf(child) {
-    const allocator = self._slab.allocator();
-    const chain = try PrototypeChain(
-        &.{ EventTarget, @TypeOf(child) },
-    ).allocate(allocator);
-
-    const event_ptr = chain.get(0);
-    event_ptr.* = .{
-        ._type = unionInit(EventTarget.Type, chain.get(1)),
-    };
-    chain.setLeaf(1, child);
-
-    return chain.get(1);
-}
-
-pub fn standaloneEventTarget(self: *Factory, child: anytype) !*EventTarget {
-    const allocator = self._slab.allocator();
-    const et = try allocator.create(EventTarget);
-    et.* = .{ ._type = unionInit(EventTarget.Type, child) };
-    return et;
-}
-
-// this is a root object
-pub fn event(self: *Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
-    const chain = try PrototypeChain(
-        &.{ Event, @TypeOf(child) },
-    ).allocate(arena);
-
-    // Special case: Event has a _type_string field, so we need manual setup
-    const event_ptr = chain.get(0);
-    event_ptr.* = try self.eventInit(arena, typ, chain.get(1));
-    chain.setLeaf(1, child);
-
-    return chain.get(1);
-}
-
-pub fn uiEvent(self: *Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
-    const chain = try PrototypeChain(
-        &.{ Event, UIEvent, @TypeOf(child) },
-    ).allocate(arena);
-
-    // Special case: Event has a _type_string field, so we need manual setup
-    const event_ptr = chain.get(0);
-    event_ptr.* = try self.eventInit(arena, typ, chain.get(1));
-    chain.setMiddle(1, UIEvent.Type);
-    chain.setLeaf(2, child);
-
-    return chain.get(2);
-}
-
-pub fn mouseEvent(self: *Factory, arena: Allocator, typ: String, mouse: MouseEvent, child: anytype) !*@TypeOf(child) {
-    const chain = try PrototypeChain(
-        &.{ Event, UIEvent, MouseEvent, @TypeOf(child) },
-    ).allocate(arena);
-
-    // Special case: Event has a _type_string field, so we need manual setup
-    const event_ptr = chain.get(0);
-    event_ptr.* = try self.eventInit(arena, typ, chain.get(1));
-    chain.setMiddle(1, UIEvent.Type);
-
-    // Set MouseEvent with all its fields
-    const mouse_ptr = chain.get(2);
-    mouse_ptr.* = mouse;
-    mouse_ptr._proto = chain.get(1);
-    mouse_ptr._type = unionInit(MouseEvent.Type, chain.get(3));
-
-    chain.setLeaf(3, child);
-
-    return chain.get(3);
-}
-
-fn eventInit(self: *const Factory, arena: Allocator, typ: String, value: anytype) !Event {
+fn eventInit(arena: Allocator, typ: String, value: anytype) !Event {
     // Round to 2ms for privacy (browsers do this)
     const raw_timestamp = @import("../datetime.zig").milliTimestamp(.monotonic);
     const time_stamp = (raw_timestamp / 2) * 2;
 
     return .{
+        ._rc = 0,
         ._arena = arena,
-        ._page = self._page,
         ._type = unionInit(Event.Type, value),
         ._type_string = typ,
         ._time_stamp = time_stamp,
@@ -384,7 +388,7 @@ pub fn destroy(self: *Factory, value: anytype) void {
     }
 
     if (comptime @hasField(S, "_proto")) {
-        self.destroyChain(value, true, 0, std.mem.Alignment.@"1");
+        self.destroyChain(value, 0, std.mem.Alignment.@"1");
     } else {
         self.destroyStandalone(value);
     }
@@ -398,7 +402,6 @@ pub fn destroyStandalone(self: *Factory, value: anytype) void {
 fn destroyChain(
     self: *Factory,
     value: anytype,
-    comptime first: bool,
     old_size: usize,
     old_align: std.mem.Alignment,
 ) void {
@@ -410,23 +413,8 @@ fn destroyChain(
     const new_size = current_size + @sizeOf(S);
     const new_align = std.mem.Alignment.max(old_align, std.mem.Alignment.of(S));
 
-    // 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, new_size, new_align);
+        self.destroyChain(value._proto, new_size, new_align);
     } else {
         // no proto so this is the head of the chain.
         // we use this as the ptr to the start of the chain.

src/browser/Mime.zig

@@ -24,10 +24,11 @@ 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,
-charset_len: usize = 5,
+charset_len: usize = default_charset_len,
 
 /// String "UTF-8" continued by null characters.
-pub const default_charset = .{ 'U', 'T', 'F', '-', '8' } ++ .{0} ** 36;
+const default_charset = .{ 'U', 'T', 'F', '-', '8' } ++ .{0} ** 36;
+const default_charset_len = 5;
 
 /// Mime with unknown Content-Type, empty params and empty charset.
 pub const unknown = Mime{ .content_type = .{ .unknown = {} } };
@@ -127,17 +128,17 @@ pub fn parse(input: []u8) !Mime {
 
     const params = trimLeft(normalized[type_len..]);
 
-    var charset: [41]u8 = undefined;
-    var charset_len: usize = undefined;
+    var charset: [41]u8 = default_charset;
+    var charset_len: usize = default_charset_len;
 
     var it = std.mem.splitScalar(u8, params, ';');
     while (it.next()) |attr| {
-        const i = std.mem.indexOfScalarPos(u8, attr, 0, '=') orelse return error.Invalid;
+        const i = std.mem.indexOfScalarPos(u8, attr, 0, '=') orelse continue;
         const name = trimLeft(attr[0..i]);
 
         const value = trimRight(attr[i + 1 ..]);
         if (value.len == 0) {
-            return error.Invalid;
+            continue;
         }
 
         const attribute_name = std.meta.stringToEnum(enum {
@@ -150,7 +151,7 @@ pub fn parse(input: []u8) !Mime {
                     break;
                 }
 
-                const attribute_value = try parseCharset(value);
+                const attribute_value = parseCharset(value) catch continue;
                 @memcpy(charset[0..attribute_value.len], attribute_value);
                 // Null-terminate right after attribute value.
                 charset[attribute_value.len] = 0;
@@ -334,6 +335,19 @@ test "Mime: invalid" {
         "text/ html",
         "text / html",
         "text/html other",
+    };
+
+    for (invalids) |invalid| {
+        const mutable_input = try testing.arena_allocator.dupe(u8, invalid);
+        try testing.expectError(error.Invalid, Mime.parse(mutable_input));
+    }
+}
+
+test "Mime: malformed parameters are ignored" {
+    defer testing.reset();
+
+    // These should all parse successfully as text/html with malformed params ignored
+    const valid_with_malformed_params = [_][]const u8{
         "text/html; x",
         "text/html; x=",
         "text/html; x=  ",
@@ -342,11 +356,13 @@ test "Mime: invalid" {
         "text/html; charset=\"\"",
         "text/html; charset=\"",
         "text/html; charset=\"\\",
+        "text/html;\"",
     };
 
-    for (invalids) |invalid| {
-        const mutable_input = try testing.arena_allocator.dupe(u8, invalid);
-        try testing.expectError(error.Invalid, Mime.parse(mutable_input));
+    for (valid_with_malformed_params) |input| {
+        const mutable_input = try testing.arena_allocator.dupe(u8, input);
+        const mime = try Mime.parse(mutable_input);
+        try testing.expectEqual(.text_html, std.meta.activeTag(mime.content_type));
     }
 }
 
@@ -435,6 +451,12 @@ test "Mime: parse charset" {
         .charset = "custom-non-standard-charset-value",
         .params = "charset=\"custom-non-standard-charset-value\"",
     }, "text/xml;charset=\"custom-non-standard-charset-value\"");
+
+    try expect(.{
+        .content_type = .{ .text_html = {} },
+        .charset = "UTF-8",
+        .params = "x=\"",
+    }, "text/html;x=\"");
 }
 
 test "Mime: isHTML" {

src/browser/ScriptManager.zig

@@ -20,13 +20,14 @@ const std = @import("std");
 const lp = @import("lightpanda");
 const builtin = @import("builtin");
 
-const js = @import("js/js.zig");
 const log = @import("../log.zig");
+const Http = @import("../http/Http.zig");
+const String = @import("../string.zig").String;
 
+const js = @import("js/js.zig");
 const URL = @import("URL.zig");
 const Page = @import("Page.zig");
 const Browser = @import("Browser.zig");
-const Http = @import("../http/Http.zig");
 
 const Element = @import("webapi/Element.zig");
 
@@ -83,6 +84,10 @@ imported_modules: std.StringHashMapUnmanaged(ImportedModule),
 // importmap contains resolved urls.
 importmap: std.StringHashMapUnmanaged([:0]const u8),
 
+// have we notified the page that all scripts are loaded (used to fire the "load"
+// event).
+page_notified_of_completion: bool,
+
 pub fn init(allocator: Allocator, http_client: *Http.Client, page: *Page) ScriptManager {
     return .{
         .page = page,
@@ -96,6 +101,7 @@ pub fn init(allocator: Allocator, http_client: *Http.Client, page: *Page) Script
         .client = http_client,
         .static_scripts_done = false,
         .buffer_pool = BufferPool.init(allocator, 5),
+        .page_notified_of_completion = false,
         .script_pool = std.heap.MemoryPool(Script).init(allocator),
     };
 }
@@ -259,6 +265,7 @@ pub fn addFromElement(self: *ScriptManager, comptime from_parser: bool, script_e
             .url = url,
             .ctx = script,
             .method = .GET,
+            .frame_id = page._frame_id,
             .headers = try self.getHeaders(url),
             .blocking = is_blocking,
             .cookie_jar = &page._session.cookie_jar,
@@ -358,9 +365,11 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .manager = self,
     };
 
+    const page = self.page;
+
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
-        self.page.js.localScope(&ls);
+        page.js.localScope(&ls);
         defer ls.deinit();
 
         log.debug(.http, "script queue", .{
@@ -375,10 +384,11 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .url = url,
         .ctx = script,
         .method = .GET,
+        .frame_id = page._frame_id,
         .headers = try self.getHeaders(url),
-        .cookie_jar = &self.page._session.cookie_jar,
+        .cookie_jar = &page._session.cookie_jar,
         .resource_type = .script,
-        .notification = self.page._session.notification,
+        .notification = page._session.notification,
         .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
         .header_callback = Script.headerCallback,
         .data_callback = Script.dataCallback,
@@ -451,9 +461,10 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
         } },
     };
 
+    const page = self.page;
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
-        self.page.js.localScope(&ls);
+        page.js.localScope(&ls);
         defer ls.deinit();
 
         log.debug(.http, "script queue", .{
@@ -476,11 +487,12 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
     try self.client.request(.{
         .url = url,
         .method = .GET,
+        .frame_id = page._frame_id,
         .headers = try self.getHeaders(url),
         .ctx = script,
         .resource_type = .script,
-        .cookie_jar = &self.page._session.cookie_jar,
-        .notification = self.page._session.notification,
+        .cookie_jar = &page._session.cookie_jar,
+        .notification = page._session.notification,
         .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
         .header_callback = Script.headerCallback,
         .data_callback = Script.dataCallback,
@@ -564,19 +576,12 @@ fn evaluate(self: *ScriptManager) void {
     // Page makes this safe to call multiple times.
     page.documentIsLoaded();
 
-    if (self.async_scripts.first == null) {
-        // Looks like all async scripts are done too!
-        // Page makes this safe to call multiple times.
-        page.documentIsComplete();
+    if (self.async_scripts.first == null and self.page_notified_of_completion == false) {
+        self.page_notified_of_completion = true;
+        page.scriptsCompletedLoading();
     }
 }
 
-pub fn isDone(self: *const ScriptManager) bool {
-    return self.static_scripts_done and // page is done processing initial html
-        self.defer_scripts.first == null and // no deferred scripts
-        self.async_scripts.first == null; // no async scripts
-}
-
 fn parseImportmap(self: *ScriptManager, script: *const Script) !void {
     const content = script.source.content();
 
@@ -617,8 +622,21 @@ pub const Script = struct {
     node: std.DoublyLinkedList.Node,
     script_element: ?*Element.Html.Script,
     manager: *ScriptManager,
+
+    // for debugging a rare production issue
     header_callback_called: bool = false,
 
+    // for debugging a rare production issue
+    debug_transfer_id: u32 = 0,
+    debug_transfer_tries: u8 = 0,
+    debug_transfer_aborted: bool = false,
+    debug_transfer_bytes_received: usize = 0,
+    debug_transfer_notified_fail: bool = false,
+    debug_transfer_redirecting: bool = false,
+    debug_transfer_intercept_state: u8 = 0,
+    debug_transfer_auth_challenge: bool = false,
+    debug_transfer_easy_id: usize = 0,
+
     const Kind = enum {
         module,
         javascript,
@@ -686,8 +704,37 @@ pub const Script = struct {
             // temp debug, trying to figure out why the next assert sometimes
             // fails. Is the buffer just corrupt or is headerCallback really
             // being called twice?
-            lp.assert(self.header_callback_called == false, "ScriptManager.Header recall", .{});
+            lp.assert(self.header_callback_called == false, "ScriptManager.Header recall", .{
+                .m = @tagName(std.meta.activeTag(self.mode)),
+                .a1 = self.debug_transfer_id,
+                .a2 = self.debug_transfer_tries,
+                .a3 = self.debug_transfer_aborted,
+                .a4 = self.debug_transfer_bytes_received,
+                .a5 = self.debug_transfer_notified_fail,
+                .a6 = self.debug_transfer_redirecting,
+                .a7 = self.debug_transfer_intercept_state,
+                .a8 = self.debug_transfer_auth_challenge,
+                .a9 = self.debug_transfer_easy_id,
+                .b1 = transfer.id,
+                .b2 = transfer._tries,
+                .b3 = transfer.aborted,
+                .b4 = transfer.bytes_received,
+                .b5 = transfer._notified_fail,
+                .b6 = transfer._redirecting,
+                .b7 = @intFromEnum(transfer._intercept_state),
+                .b8 = transfer._auth_challenge != null,
+                .b9 = if (transfer._conn) |c| @intFromPtr(c.easy) else 0,
+            });
             self.header_callback_called = true;
+            self.debug_transfer_id = transfer.id;
+            self.debug_transfer_tries = transfer._tries;
+            self.debug_transfer_aborted = transfer.aborted;
+            self.debug_transfer_bytes_received = transfer.bytes_received;
+            self.debug_transfer_notified_fail = transfer._notified_fail;
+            self.debug_transfer_redirecting = transfer._redirecting;
+            self.debug_transfer_intercept_state = @intFromEnum(transfer._intercept_state);
+            self.debug_transfer_auth_challenge = transfer._auth_challenge != null;
+            self.debug_transfer_easy_id = if (transfer._conn) |c| @intFromPtr(c.easy) else 0;
         }
 
         lp.assert(self.source.remote.capacity == 0, "ScriptManager.Header buffer", .{ .capacity = self.source.remote.capacity });
@@ -820,13 +867,15 @@ pub const Script = struct {
                     .kind = self.kind,
                     .cacheable = cacheable,
                 });
-                self.executeCallback("error", local.toLocal(script_element._on_error), page);
+                self.executeCallback(comptime .wrap("error"), page);
                 return;
             };
-            self.executeCallback("load", local.toLocal(script_element._on_load), page);
+            self.executeCallback(comptime .wrap("load"), page);
             return;
         }
 
+        defer page._event_manager.clearIgnoreList();
+
         var try_catch: js.TryCatch = undefined;
         try_catch.init(local);
         defer try_catch.deinit();
@@ -845,19 +894,18 @@ pub const Script = struct {
         };
 
         if (comptime IS_DEBUG) {
-            log.debug(.browser, "executed script", .{ .src = url, .success = success, .on_load = script_element._on_load != null });
+            log.debug(.browser, "executed script", .{ .src = url, .success = success });
         }
 
         defer {
-            // We should run microtasks even if script execution fails.
-            local.runMicrotasks();
+            local.runMacrotasks(); // also runs microtasks
             _ = page.js.scheduler.run() catch |err| {
                 log.err(.page, "scheduler", .{ .err = err });
             };
         }
 
         if (success) {
-            self.executeCallback("load", local.toLocal(script_element._on_load), page);
+            self.executeCallback(comptime .wrap("load"), page);
             return;
         }
 
@@ -868,14 +916,12 @@ pub const Script = struct {
             .cacheable = cacheable,
         });
 
-        self.executeCallback("error", local.toLocal(script_element._on_error), page);
+        self.executeCallback(comptime .wrap("error"), page);
     }
 
-    fn executeCallback(self: *const Script, comptime typ: []const u8, cb_: ?js.Function, page: *Page) void {
-        const cb = cb_ orelse return;
-
+    fn executeCallback(self: *const Script, typ: String, page: *Page) void {
         const Event = @import("webapi/Event.zig");
-        const event = Event.initTrusted(comptime .wrap(typ), .{}, page) catch |err| {
+        const event = Event.initTrusted(typ, .{}, page) catch |err| {
             log.warn(.js, "script internal callback", .{
                 .url = self.url,
                 .type = typ,
@@ -883,14 +929,11 @@ pub const Script = struct {
             });
             return;
         };
-        defer if (!event._v8_handoff) event.deinit(false);
-
-        var caught: js.TryCatch.Caught = undefined;
-        cb.tryCall(void, .{event}, &caught) catch {
+        page._event_manager.dispatchOpts(self.script_element.?.asNode().asEventTarget(), event, .{ .apply_ignore = true }) catch |err| {
             log.warn(.js, "script callback", .{
                 .url = self.url,
                 .type = typ,
-                .caught = caught,
+                .err = err,
             });
         };
     }
@@ -1010,23 +1053,35 @@ fn parseDataURI(allocator: Allocator, src: []const u8) !?[]const u8 {
 
     const uri = src[5..];
     const data_starts = std.mem.indexOfScalar(u8, uri, ',') orelse return null;
+    const data = uri[data_starts + 1 ..];
 
-    var data = uri[data_starts + 1 ..];
+    const unescaped = try URL.unescape(allocator, data);
 
-    // Extract the encoding.
     const metadata = uri[0..data_starts];
-    if (std.mem.endsWith(u8, metadata, ";base64")) {
-        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;
+    if (std.mem.endsWith(u8, metadata, ";base64") == false) {
+        return unescaped;
     }
 
-    return data;
+    // Forgiving base64 decode per WHATWG spec:
+    // https://infra.spec.whatwg.org/#forgiving-base64-decode
+    // Step 1: Remove all ASCII whitespace
+    var stripped = try std.ArrayList(u8).initCapacity(allocator, unescaped.len);
+    for (unescaped) |c| {
+        if (!std.ascii.isWhitespace(c)) {
+            stripped.appendAssumeCapacity(c);
+        }
+    }
+    const trimmed = std.mem.trimRight(u8, stripped.items, "=");
+
+    // Length % 4 == 1 is invalid
+    if (trimmed.len % 4 == 1) {
+        return error.InvalidCharacterError;
+    }
+
+    const decoded_size = std.base64.standard_no_pad.Decoder.calcSizeForSlice(trimmed) catch return error.InvalidCharacterError;
+    const buffer = try allocator.alloc(u8, decoded_size);
+    std.base64.standard_no_pad.Decoder.decode(buffer, trimmed) catch return error.InvalidCharacterError;
+    return buffer;
 }
 
 const testing = @import("../testing.zig");

src/browser/Session.zig

@@ -18,6 +18,7 @@
 
 const std = @import("std");
 const lp = @import("lightpanda");
+const builtin = @import("builtin");
 
 const log = @import("../log.zig");
 
@@ -31,7 +32,7 @@ const Browser = @import("Browser.zig");
 const Notification = @import("../Notification.zig");
 
 const Allocator = std.mem.Allocator;
-const IS_DEBUG = @import("builtin").mode == .Debug;
+const IS_DEBUG = builtin.mode == .Debug;
 
 // Session is like a browser's tab.
 // It owns the js env and the loader for all the pages of the session.
@@ -45,16 +46,6 @@ notification: *Notification,
 // 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,
-
 cookie_jar: storage.Cookie.Jar,
 storage_shed: storage.Shed,
 
@@ -63,24 +54,23 @@ navigation: Navigation,
 
 page: ?Page,
 
+frame_id_gen: u32,
+
 pub fn init(self: *Session, browser: *Browser, notification: *Notification) !void {
     const allocator = browser.app.allocator;
     const arena = try browser.arena_pool.acquire();
     errdefer browser.arena_pool.release(arena);
 
-    const transfer_arena = try browser.arena_pool.acquire();
-    errdefer browser.arena_pool.release(transfer_arena);
-
     self.* = .{
         .page = null,
         .arena = arena,
         .history = .{},
+        .frame_id_gen = 0,
         // The prototype (EventTarget) for Navigation is created when a Page is created.
         .navigation = .{ ._proto = undefined },
         .storage_shed = .{},
         .browser = browser,
         .notification = notification,
-        .transfer_arena = transfer_arena,
         .cookie_jar = storage.Cookie.Jar.init(allocator),
     };
 }
@@ -93,7 +83,6 @@ pub fn deinit(self: *Session) void {
 
     self.cookie_jar.deinit();
     self.storage_shed.deinit(browser.app.allocator);
-    browser.arena_pool.release(self.transfer_arena);
     browser.arena_pool.release(self.arena);
 }
 
@@ -104,7 +93,7 @@ pub fn createPage(self: *Session) !*Page {
 
     self.page = @as(Page, undefined);
     const page = &self.page.?;
-    try Page.init(page, self);
+    try Page.init(page, self.nextFrameId(), self, null);
 
     // Creates a new NavigationEventTarget for this page.
     try self.navigation.onNewPage(page);
@@ -140,12 +129,17 @@ pub fn replacePage(self: *Session) !*Page {
     }
 
     lp.assert(self.page != null, "Session.replacePage null page", .{});
-    self.page.?.deinit();
+
+    var current = self.page.?;
+    const frame_id = current._frame_id;
+    const parent = current.parent;
+    current.deinit();
+
     self.browser.env.memoryPressureNotification(.moderate);
 
     self.page = @as(Page, undefined);
     const page = &self.page.?;
-    try Page.init(page, self);
+    try Page.init(page, frame_id, self, parent);
     return page;
 }
 
@@ -159,53 +153,232 @@ pub const WaitResult = enum {
     cdp_socket,
 };
 
+pub fn findPage(self: *Session, frame_id: u32) ?*Page {
+    const page = self.currentPage() orelse return null;
+    return if (page._frame_id == frame_id) page else null;
+}
+
 pub fn wait(self: *Session, wait_ms: u32) WaitResult {
+    var page = &(self.page orelse return .no_page);
     while (true) {
-        if (self.page) |*page| {
-            switch (page.wait(wait_ms)) {
-                .done => {
-                    if (page._queued_navigation == null) {
-                        return .done;
-                    }
-                    self.processScheduledNavigation() catch return .done;
-                },
-                else => |result| return result,
+        const wait_result = self._wait(page, wait_ms) catch |err| {
+            switch (err) {
+                error.JsError => {}, // already logged (with hopefully more context)
+                else => log.err(.browser, "session wait", .{
+                    .err = err,
+                    .url = page.url,
+                }),
             }
-        } else {
-            return .no_page;
+            return .done;
+        };
+
+        switch (wait_result) {
+            .done => {
+                if (page._queued_navigation == null) {
+                    return .done;
+                }
+                page = self.processScheduledNavigation(page) catch return .done;
+            },
+            else => |result| return result,
         }
-        // if we've successfull navigated, we'll give the new page another
-        // page.wait(wait_ms)
     }
 }
 
-fn processScheduledNavigation(self: *Session) !void {
-    defer self.browser.arena_pool.reset(self.transfer_arena, 4 * 1024);
-    const url, const opts = blk: {
-        const qn = self.page.?._queued_navigation.?;
-        // qn might not be safe to use after self.removePage is called, hence
-        // this block;
-        const url = qn.url;
-        const opts = qn.opts;
+fn _wait(self: *Session, page: *Page, wait_ms: u32) !WaitResult {
+    var timer = try std.time.Timer.start();
+    var ms_remaining = wait_ms;
 
-        // 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();
+    const browser = self.browser;
+    var http_client = browser.http_client;
+
+    // I'd like the page to know NOTHING about cdp_socket / CDP, but the
+    // fact is that the behavior of wait changes depending on whether or
+    // not we're using CDP.
+    // If we aren't using CDP, as soon as we think there's nothing left
+    // to do, we can exit - we'de done.
+    // But if we are using CDP, we should wait for the whole `wait_ms`
+    // because the http_click.tick() also monitors the CDP socket. And while
+    // we could let CDP poll http (like it does for HTTP requests), the fact
+    // is that we know more about the timing of stuff (e.g. how long to
+    // poll/sleep) in the page.
+    const exit_when_done = http_client.cdp_client == null;
+
+    while (true) {
+        switch (page._parse_state) {
+            .pre, .raw, .text, .image => {
+                // The main page hasn't started/finished navigating.
+                // There's no JS to run, and no reason to run the scheduler.
+                if (http_client.active == 0 and exit_when_done) {
+                    // haven't started navigating, I guess.
+                    return .done;
+                }
+                // Either we have active http connections, or we're in CDP
+                // mode with an extra socket. Either way, we're waiting
+                // for http traffic
+                if (try http_client.tick(@intCast(ms_remaining)) == .cdp_socket) {
+                    // exit_when_done is explicitly set when there isn't
+                    // an extra socket, so it should not be possibl to
+                    // get an cdp_socket message when exit_when_done
+                    // is true.
+                    if (IS_DEBUG) {
+                        std.debug.assert(exit_when_done == false);
+                    }
+
+                    // data on a socket we aren't handling, return to caller
+                    return .cdp_socket;
+                }
+            },
+            .html, .complete => {
+                if (page._queued_navigation != null) {
+                    return .done;
+                }
+
+                // The HTML page was parsed. We now either have JS scripts to
+                // download, or scheduled tasks to execute, or both.
+
+                // scheduler.run could trigger new http transfers, so do not
+                // store http_client.active BEFORE this call and then use
+                // it AFTER.
+                const ms_to_next_task = try browser.runMacrotasks();
+
+                // Each call to this runs scheduled load events.
+                try page.dispatchLoad();
+
+                const http_active = http_client.active;
+                const total_network_activity = http_active + http_client.intercepted;
+                if (page._notified_network_almost_idle.check(total_network_activity <= 2)) {
+                    page.notifyNetworkAlmostIdle();
+                }
+                if (page._notified_network_idle.check(total_network_activity == 0)) {
+                    page.notifyNetworkIdle();
+                }
+
+                if (http_active == 0 and exit_when_done) {
+                    // we don't need to consider http_client.intercepted here
+                    // because exit_when_done is true, and that can only be
+                    // the case when interception isn't possible.
+                    if (comptime IS_DEBUG) {
+                        std.debug.assert(http_client.intercepted == 0);
+                    }
+
+                    const ms: u64 = ms_to_next_task orelse blk: {
+                        if (wait_ms - ms_remaining < 100) {
+                            if (comptime builtin.is_test) {
+                                return .done;
+                            }
+                            // Look, we want to exit ASAP, but we don't want
+                            // to exit so fast that we've run none of the
+                            // background jobs.
+                            break :blk 50;
+                        }
+
+                        if (browser.hasBackgroundTasks()) {
+                            // _we_ have nothing to run, but v8 is working on
+                            // background tasks. We'll wait for them.
+                            browser.waitForBackgroundTasks();
+                            break :blk 20;
+                        }
+
+                        // No http transfers, no cdp extra socket, no
+                        // scheduled tasks, we're done.
+                        return .done;
+                    };
+
+                    if (ms > ms_remaining) {
+                        // Same as above, except we have a scheduled task,
+                        // it just happens to be too far into the future
+                        // compared to how long we were told to wait.
+                        return .done;
+                    }
+
+                    // We have a task to run in the not-so-distant future.
+                    // You might think we can just sleep until that task is
+                    // ready, but we should continue to run lowPriority tasks
+                    // in the meantime, and that could unblock things. So
+                    // we'll just sleep for a bit, and then restart our wait
+                    // loop to see if anything new can be processed.
+                    std.Thread.sleep(std.time.ns_per_ms * @as(u64, @intCast(@min(ms, 20))));
+                } else {
+                    // We're here because we either have active HTTP
+                    // connections, or exit_when_done == false (aka, there's
+                    // an cdp_socket registered with the http client).
+                    // We should continue to run lowPriority tasks, so we
+                    // minimize how long we'll poll for network I/O.
+                    var ms_to_wait = @min(200, ms_to_next_task orelse 200);
+                    if (ms_to_wait > 10 and browser.hasBackgroundTasks()) {
+                        // if we have background tasks, we don't want to wait too
+                        // long for a message from the client. We want to go back
+                        // to the top of the loop and run macrotasks.
+                        ms_to_wait = 10;
+                    }
+                    if (try http_client.tick(@min(ms_remaining, ms_to_wait)) == .cdp_socket) {
+                        // data on a socket we aren't handling, return to caller
+                        return .cdp_socket;
+                    }
+                }
+            },
+            .err => |err| {
+                page._parse_state = .{ .raw_done = @errorName(err) };
+                return err;
+            },
+            .raw_done => {
+                if (exit_when_done) {
+                    return .done;
+                }
+                // we _could_ http_client.tick(ms_to_wait), but this has
+                // the same result, and I feel is more correct.
+                return .no_page;
+            },
+        }
+
+        const ms_elapsed = timer.lap() / 1_000_000;
+        if (ms_elapsed >= ms_remaining) {
+            return .done;
+        }
+        ms_remaining -= @intCast(ms_elapsed);
+    }
+}
+
+fn processScheduledNavigation(self: *Session, current_page: *Page) !*Page {
+    const browser = self.browser;
+
+    const qn = current_page._queued_navigation.?;
+    // take ownership of the page's queued navigation
+    current_page._queued_navigation = null;
+    defer browser.arena_pool.release(qn.arena);
+
+    const frame_id, const parent = blk: {
+        const page = &self.page.?;
+        const frame_id = page._frame_id;
+        const parent = page.parent;
+
+        browser.http_client.abort();
         self.removePage();
 
-        break :blk .{ url, opts };
+        break :blk .{ frame_id, parent };
     };
 
-    const page = self.createPage() catch |err| {
-        log.err(.browser, "queued navigation page error", .{
-            .err = err,
-            .url = url,
-        });
+    self.page = @as(Page, undefined);
+    const page = &self.page.?;
+    try Page.init(page, frame_id, self, parent);
+
+    // Creates a new NavigationEventTarget for this page.
+    try self.navigation.onNewPage(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.notification.dispatch(.page_created, page);
+
+    page.navigate(qn.url, qn.opts) catch |err| {
+        log.err(.browser, "queued navigation error", .{ .err = err, .url = qn.url });
         return err;
     };
 
-    page.navigate(url, opts) catch |err| {
-        log.err(.browser, "queued navigation error", .{ .err = err, .url = url });
-        return err;
-    };
+    return page;
+}
+
+pub fn nextFrameId(self: *Session) u32 {
+    const id = self.frame_id_gen +% 1;
+    self.frame_id_gen = id;
+    return id;
 }

src/browser/URL.zig

@@ -20,44 +20,61 @@ const std = @import("std");
 const Allocator = std.mem.Allocator;
 
 const ResolveOpts = struct {
+    encode: bool = false,
     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);
+            const duped = try allocator.dupeZ(u8, path);
+            return processResolved(allocator, duped, opts);
+        }
+        if (comptime opts.encode) {
+            return processResolved(allocator, path, opts);
         }
         return path;
     }
 
     if (path.len == 0) {
         if (comptime opts.always_dupe) {
-            return allocator.dupeZ(u8, base);
+            const duped = try allocator.dupeZ(u8, base);
+            return processResolved(allocator, duped, opts);
+        }
+        if (comptime opts.encode) {
+            return processResolved(allocator, base, opts);
         }
         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 });
+        const result = try std.mem.joinZ(allocator, "", &.{ base[0..base_path_end], path });
+        return processResolved(allocator, result, opts);
     }
     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 });
+        const result = try std.mem.joinZ(allocator, "", &.{ base[0..base_fragment_start], path });
+        return processResolved(allocator, result, opts);
     }
 
     if (std.mem.startsWith(u8, path, "//")) {
         // network-path reference
         const index = std.mem.indexOfScalar(u8, base, ':') orelse {
             if (comptime isNullTerminated(PT)) {
+                if (comptime opts.encode) {
+                    return processResolved(allocator, path, opts);
+                }
                 return path;
             }
-            return allocator.dupeZ(u8, path);
+            const duped = try allocator.dupeZ(u8, path);
+            return processResolved(allocator, duped, opts);
         };
         const protocol = base[0 .. index + 1];
-        return std.mem.joinZ(allocator, "", &.{ protocol, path });
+        const result = try std.mem.joinZ(allocator, "", &.{ protocol, path });
+        return processResolved(allocator, result, opts);
     }
 
     const scheme_end = std.mem.indexOf(u8, base, "://");
@@ -65,7 +82,8 @@ pub fn resolve(allocator: Allocator, base: [:0]const u8, path: anytype, comptime
     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 });
+        const result = try std.mem.joinZ(allocator, "", &.{ base[0..path_start], path });
+        return processResolved(allocator, result, opts);
     }
 
     var normalized_base: []const u8 = base[0..path_start];
@@ -127,7 +145,119 @@ pub fn resolve(allocator: Allocator, base: [:0]const u8, path: anytype, comptime
 
     // we always have an extra space
     out[out_i] = 0;
-    return out[0..out_i :0];
+    return processResolved(allocator, out[0..out_i :0], opts);
+}
+
+fn processResolved(allocator: Allocator, url: [:0]const u8, comptime opts: ResolveOpts) ![:0]const u8 {
+    if (!comptime opts.encode) {
+        return url;
+    }
+    return ensureEncoded(allocator, url);
+}
+
+pub fn ensureEncoded(allocator: Allocator, url: [:0]const u8) ![:0]const u8 {
+    const scheme_end = std.mem.indexOf(u8, url, "://");
+    const authority_start = if (scheme_end) |end| end + 3 else 0;
+    const path_start = std.mem.indexOfScalarPos(u8, url, authority_start, '/') orelse return url;
+
+    const query_start = std.mem.indexOfScalarPos(u8, url, path_start, '?');
+    const fragment_start = std.mem.indexOfScalarPos(u8, url, query_start orelse path_start, '#');
+
+    const path_end = query_start orelse fragment_start orelse url.len;
+    const query_end = if (query_start) |_| (fragment_start orelse url.len) else path_end;
+
+    const path_to_encode = url[path_start..path_end];
+    const encoded_path = try percentEncodeSegment(allocator, path_to_encode, true);
+
+    const encoded_query = if (query_start) |qs| blk: {
+        const query_to_encode = url[qs + 1 .. query_end];
+        const encoded = try percentEncodeSegment(allocator, query_to_encode, false);
+        break :blk encoded;
+    } else null;
+
+    const encoded_fragment = if (fragment_start) |fs| blk: {
+        const fragment_to_encode = url[fs + 1 ..];
+        const encoded = try percentEncodeSegment(allocator, fragment_to_encode, false);
+        break :blk encoded;
+    } else null;
+
+    if (encoded_path.ptr == path_to_encode.ptr and
+        (encoded_query == null or encoded_query.?.ptr == url[query_start.? + 1 .. query_end].ptr) and
+        (encoded_fragment == null or encoded_fragment.?.ptr == url[fragment_start.? + 1 ..].ptr))
+    {
+        // nothing has changed
+        return url;
+    }
+
+    var buf = try std.ArrayList(u8).initCapacity(allocator, url.len + 20);
+    try buf.appendSlice(allocator, url[0..path_start]);
+    try buf.appendSlice(allocator, encoded_path);
+    if (encoded_query) |eq| {
+        try buf.append(allocator, '?');
+        try buf.appendSlice(allocator, eq);
+    }
+    if (encoded_fragment) |ef| {
+        try buf.append(allocator, '#');
+        try buf.appendSlice(allocator, ef);
+    }
+    try buf.append(allocator, 0);
+    return buf.items[0 .. buf.items.len - 1 :0];
+}
+
+fn percentEncodeSegment(allocator: Allocator, segment: []const u8, comptime is_path: bool) ![]const u8 {
+    // Check if encoding is needed
+    var needs_encoding = false;
+    for (segment) |c| {
+        if (shouldPercentEncode(c, is_path)) {
+            needs_encoding = true;
+            break;
+        }
+    }
+    if (!needs_encoding) {
+        return segment;
+    }
+
+    var buf = try std.ArrayList(u8).initCapacity(allocator, segment.len + 10);
+
+    var i: usize = 0;
+    while (i < segment.len) : (i += 1) {
+        const c = segment[i];
+
+        // Check if this is an already-encoded sequence (%XX)
+        if (c == '%' and i + 2 < segment.len) {
+            const end = i + 2;
+            const h1 = segment[i + 1];
+            const h2 = segment[end];
+            if (std.ascii.isHex(h1) and std.ascii.isHex(h2)) {
+                try buf.appendSlice(allocator, segment[i .. end + 1]);
+                i = end;
+                continue;
+            }
+        }
+
+        if (shouldPercentEncode(c, is_path)) {
+            try buf.writer(allocator).print("%{X:0>2}", .{c});
+        } else {
+            try buf.append(allocator, c);
+        }
+    }
+
+    return buf.items;
+}
+
+fn shouldPercentEncode(c: u8, comptime is_path: bool) bool {
+    return switch (c) {
+        // Unreserved characters (RFC 3986)
+        'A'...'Z', 'a'...'z', '0'...'9', '-', '.', '_', '~' => false,
+        // sub-delims allowed in both path and query
+        '!', '$', '&', '\'', '(', ')', '*', '+', ',', ';', '=' => false,
+        // Separators allowed in both path and query
+        '/', ':', '@' => false,
+        // Query-specific: '?' is allowed in queries but not in paths
+        '?' => comptime is_path,
+        // Everything else needs encoding (including space)
+        else => true,
+    };
 }
 
 fn isNullTerminated(comptime value: type) bool {
@@ -512,6 +642,33 @@ pub fn getRobotsUrl(arena: Allocator, url: [:0]const u8) ![:0]const u8 {
     );
 }
 
+pub fn unescape(arena: Allocator, input: []const u8) ![]const u8 {
+    if (std.mem.indexOfScalar(u8, input, '%') == null) {
+        return input;
+    }
+
+    var result = try std.ArrayList(u8).initCapacity(arena, input.len);
+
+    var i: usize = 0;
+    while (i < input.len) {
+        if (input[i] == '%' and i + 2 < input.len) {
+            const hex = input[i + 1 .. i + 3];
+            const byte = std.fmt.parseInt(u8, hex, 16) catch {
+                result.appendAssumeCapacity(input[i]);
+                i += 1;
+                continue;
+            };
+            result.appendAssumeCapacity(byte);
+            i += 3;
+        } else {
+            result.appendAssumeCapacity(input[i]);
+            i += 1;
+        }
+    }
+
+    return result.items;
+}
+
 const testing = @import("../testing.zig");
 test "URL: isCompleteHTTPUrl" {
     try testing.expectEqual(true, isCompleteHTTPUrl("http://example.com/about"));
@@ -691,6 +848,297 @@ test "URL: resolve" {
     }
 }
 
+test "URL: ensureEncoded" {
+    defer testing.reset();
+
+    const Case = struct {
+        url: [:0]const u8,
+        expected: [:0]const u8,
+    };
+
+    const cases = [_]Case{
+        .{
+            .url = "https://example.com/over 9000!",
+            .expected = "https://example.com/over%209000!",
+        },
+        .{
+            .url = "http://example.com/hello world.html",
+            .expected = "http://example.com/hello%20world.html",
+        },
+        .{
+            .url = "https://example.com/file[1].html",
+            .expected = "https://example.com/file%5B1%5D.html",
+        },
+        .{
+            .url = "https://example.com/file{name}.html",
+            .expected = "https://example.com/file%7Bname%7D.html",
+        },
+        .{
+            .url = "https://example.com/page?query=hello world",
+            .expected = "https://example.com/page?query=hello%20world",
+        },
+        .{
+            .url = "https://example.com/page?a=1&b=value with spaces",
+            .expected = "https://example.com/page?a=1&b=value%20with%20spaces",
+        },
+        .{
+            .url = "https://example.com/page#section one",
+            .expected = "https://example.com/page#section%20one",
+        },
+        .{
+            .url = "https://example.com/my path?query=my value#my anchor",
+            .expected = "https://example.com/my%20path?query=my%20value#my%20anchor",
+        },
+        .{
+            .url = "https://example.com/already%20encoded",
+            .expected = "https://example.com/already%20encoded",
+        },
+        .{
+            .url = "https://example.com/file%5B1%5D.html",
+            .expected = "https://example.com/file%5B1%5D.html",
+        },
+        .{
+            .url = "https://example.com/caf%C3%A9",
+            .expected = "https://example.com/caf%C3%A9",
+        },
+        .{
+            .url = "https://example.com/page?query=already%20encoded",
+            .expected = "https://example.com/page?query=already%20encoded",
+        },
+        .{
+            .url = "https://example.com/page?a=1&b=value%20here",
+            .expected = "https://example.com/page?a=1&b=value%20here",
+        },
+        .{
+            .url = "https://example.com/page#section%20one",
+            .expected = "https://example.com/page#section%20one",
+        },
+        .{
+            .url = "https://example.com/part%20encoded and not",
+            .expected = "https://example.com/part%20encoded%20and%20not",
+        },
+        .{
+            .url = "https://example.com/page?a=encoded%20value&b=not encoded",
+            .expected = "https://example.com/page?a=encoded%20value&b=not%20encoded",
+        },
+        .{
+            .url = "https://example.com/my%20path?query=not encoded#encoded%20anchor",
+            .expected = "https://example.com/my%20path?query=not%20encoded#encoded%20anchor",
+        },
+        .{
+            .url = "https://example.com/fully%20encoded?query=also%20encoded#and%20this",
+            .expected = "https://example.com/fully%20encoded?query=also%20encoded#and%20this",
+        },
+        .{
+            .url = "https://example.com/path-with_under~tilde",
+            .expected = "https://example.com/path-with_under~tilde",
+        },
+        .{
+            .url = "https://example.com/sub-delims!$&'()*+,;=",
+            .expected = "https://example.com/sub-delims!$&'()*+,;=",
+        },
+        .{
+            .url = "https://example.com",
+            .expected = "https://example.com",
+        },
+        .{
+            .url = "https://example.com?query=value",
+            .expected = "https://example.com?query=value",
+        },
+        .{
+            .url = "https://example.com/clean/path",
+            .expected = "https://example.com/clean/path",
+        },
+        .{
+            .url = "https://example.com/path?clean=query#clean-fragment",
+            .expected = "https://example.com/path?clean=query#clean-fragment",
+        },
+        .{
+            .url = "https://example.com/100% complete",
+            .expected = "https://example.com/100%25%20complete",
+        },
+        .{
+            .url = "https://example.com/path?value=100% done",
+            .expected = "https://example.com/path?value=100%25%20done",
+        },
+        .{
+            .url = "about:blank",
+            .expected = "about:blank",
+        },
+    };
+
+    for (cases) |case| {
+        const result = try ensureEncoded(testing.arena_allocator, case.url);
+        try testing.expectString(case.expected, result);
+    }
+}
+
+test "URL: resolve with encoding" {
+    defer testing.reset();
+
+    const Case = struct {
+        base: [:0]const u8,
+        path: [:0]const u8,
+        expected: [:0]const u8,
+    };
+
+    const cases = [_]Case{
+        // Spaces should be encoded as %20, but ! is allowed
+        .{
+            .base = "https://example.com/dir/",
+            .path = "over 9000!",
+            .expected = "https://example.com/dir/over%209000!",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "hello world.html",
+            .expected = "https://example.com/hello%20world.html",
+        },
+        // Multiple spaces
+        .{
+            .base = "https://example.com/",
+            .path = "path with  multiple   spaces",
+            .expected = "https://example.com/path%20with%20%20multiple%20%20%20spaces",
+        },
+        // Special characters that need encoding
+        .{
+            .base = "https://example.com/",
+            .path = "file[1].html",
+            .expected = "https://example.com/file%5B1%5D.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file{name}.html",
+            .expected = "https://example.com/file%7Bname%7D.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file<test>.html",
+            .expected = "https://example.com/file%3Ctest%3E.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file\"quote\".html",
+            .expected = "https://example.com/file%22quote%22.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file|pipe.html",
+            .expected = "https://example.com/file%7Cpipe.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file\\backslash.html",
+            .expected = "https://example.com/file%5Cbackslash.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file^caret.html",
+            .expected = "https://example.com/file%5Ecaret.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file`backtick`.html",
+            .expected = "https://example.com/file%60backtick%60.html",
+        },
+        // Characters that should NOT be encoded
+        .{
+            .base = "https://example.com/",
+            .path = "path-with_under~tilde.html",
+            .expected = "https://example.com/path-with_under~tilde.html",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "path/with/slashes",
+            .expected = "https://example.com/path/with/slashes",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "sub-delims!$&'()*+,;=.html",
+            .expected = "https://example.com/sub-delims!$&'()*+,;=.html",
+        },
+        // Already encoded characters should not be double-encoded
+        .{
+            .base = "https://example.com/",
+            .path = "already%20encoded",
+            .expected = "https://example.com/already%20encoded",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file%5B1%5D.html",
+            .expected = "https://example.com/file%5B1%5D.html",
+        },
+        // Mix of encoded and unencoded
+        .{
+            .base = "https://example.com/",
+            .path = "part%20encoded and not",
+            .expected = "https://example.com/part%20encoded%20and%20not",
+        },
+        // Query strings and fragments ARE encoded
+        .{
+            .base = "https://example.com/",
+            .path = "file name.html?query=value with spaces",
+            .expected = "https://example.com/file%20name.html?query=value%20with%20spaces",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file name.html#anchor with spaces",
+            .expected = "https://example.com/file%20name.html#anchor%20with%20spaces",
+        },
+        .{
+            .base = "https://example.com/",
+            .path = "file.html?hello=world !",
+            .expected = "https://example.com/file.html?hello=world%20!",
+        },
+        // Query structural characters should NOT be encoded
+        .{
+            .base = "https://example.com/",
+            .path = "file.html?a=1&b=2",
+            .expected = "https://example.com/file.html?a=1&b=2",
+        },
+        // Relative paths with encoding
+        .{
+            .base = "https://example.com/dir/page.html",
+            .path = "../other dir/file.html",
+            .expected = "https://example.com/other%20dir/file.html",
+        },
+        .{
+            .base = "https://example.com/dir/",
+            .path = "./sub dir/file.html",
+            .expected = "https://example.com/dir/sub%20dir/file.html",
+        },
+        // Absolute paths with encoding
+        .{
+            .base = "https://example.com/some/path",
+            .path = "/absolute path/file.html",
+            .expected = "https://example.com/absolute%20path/file.html",
+        },
+        // Unicode/high bytes (though ideally these should be UTF-8 encoded first)
+        .{
+            .base = "https://example.com/",
+            .path = "café",
+            .expected = "https://example.com/caf%C3%A9",
+        },
+        // Empty path
+        .{
+            .base = "https://example.com/",
+            .path = "",
+            .expected = "https://example.com/",
+        },
+        // Complete URL as path (should not be encoded)
+        .{
+            .base = "https://example.com/",
+            .path = "https://other.com/path with spaces",
+            .expected = "https://other.com/path%20with%20spaces",
+        },
+    };
+
+    for (cases) |case| {
+        const result = try resolve(testing.arena_allocator, case.base, case.path, .{ .encode = true });
+        try testing.expectString(case.expected, result);
+    }
+}
+
 test "URL: eqlDocument" {
     defer testing.reset();
     {
@@ -816,3 +1264,68 @@ test "URL: getRobotsUrl" {
         try testing.expectString("https://example.com/robots.txt", url);
     }
 }
+
+test "URL: unescape" {
+    defer testing.reset();
+    const arena = testing.arena_allocator;
+
+    {
+        const result = try unescape(arena, "hello world");
+        try testing.expectEqual("hello world", result);
+    }
+
+    {
+        const result = try unescape(arena, "hello%20world");
+        try testing.expectEqual("hello world", result);
+    }
+
+    {
+        const result = try unescape(arena, "%48%65%6c%6c%6f");
+        try testing.expectEqual("Hello", result);
+    }
+
+    {
+        const result = try unescape(arena, "%48%65%6C%6C%6F");
+        try testing.expectEqual("Hello", result);
+    }
+
+    {
+        const result = try unescape(arena, "a%3Db");
+        try testing.expectEqual("a=b", result);
+    }
+
+    {
+        const result = try unescape(arena, "a%3DB");
+        try testing.expectEqual("a=B", result);
+    }
+
+    {
+        const result = try unescape(arena, "ZDIgPSAndHdvJzs%3D");
+        try testing.expectEqual("ZDIgPSAndHdvJzs=", result);
+    }
+
+    {
+        const result = try unescape(arena, "%5a%44%4d%67%50%53%41%6e%64%47%68%79%5a%57%55%6e%4f%77%3D%3D");
+        try testing.expectEqual("ZDMgPSAndGhyZWUnOw==", result);
+    }
+
+    {
+        const result = try unescape(arena, "hello%2world");
+        try testing.expectEqual("hello%2world", result);
+    }
+
+    {
+        const result = try unescape(arena, "hello%ZZworld");
+        try testing.expectEqual("hello%ZZworld", result);
+    }
+
+    {
+        const result = try unescape(arena, "hello%");
+        try testing.expectEqual("hello%", result);
+    }
+
+    {
+        const result = try unescape(arena, "hello%2");
+        try testing.expectEqual("hello%2", result);
+    }
+}

src/browser/css/Tokenizer.zig

@@ -480,10 +480,11 @@ fn consumeName(self: *Tokenizer) []const u8 {
                 self.consumeEscape();
             },
             0x0 => self.advance(1),
-            '\x80'...'\xBF', '\xC0'...'\xEF', '\xF0'...'\xFF' => {
-                // This byte *is* part of a multi-byte code point,
-                // we’ll end up copying the whole code point before this loop does something else.
-                self.advance(1);
+            '\x80'...'\xFF' => {
+                // Non-ASCII: advance over the complete UTF-8 code point in one step.
+                // Using consumeChar() instead of advance(1) ensures we never land on
+                // a continuation byte, which advance() asserts against.
+                self.consumeChar();
             },
             else => {
                 if (self.hasNonAsciiAt(0)) {
@@ -583,7 +584,7 @@ fn consumeNumeric(self: *Tokenizer) Token {
             };
 
             self.advance(2);
-        } else if (self.hasAtLeast(1) and std.ascii.isDigit(self.byteAt(2))) {
+        } else if (self.hasAtLeast(2) and std.ascii.isDigit(self.byteAt(2))) {
             self.advance(1);
         } else {
             break :blk;

src/browser/dump.zig

@@ -20,16 +20,15 @@ const std = @import("std");
 const Page = @import("Page.zig");
 const Node = @import("webapi/Node.zig");
 const Slot = @import("webapi/element/html/Slot.zig");
+const IFrame = @import("webapi/element/html/IFrame.zig");
 
-pub const RootOpts = struct {
-    with_base: bool = false,
-    strip: Opts.Strip = .{},
-    shadow: Opts.Shadow = .rendered,
-};
+const IS_DEBUG = @import("builtin").mode == .Debug;
 
 pub const Opts = struct {
-    strip: Strip = .{},
-    shadow: Shadow = .rendered,
+    with_base: bool = false,
+    with_frames: bool = false,
+    strip: Opts.Strip = .{},
+    shadow: Opts.Shadow = .rendered,
 
     pub const Strip = struct {
         js: bool = false,
@@ -49,7 +48,7 @@ pub const Opts = struct {
     };
 };
 
-pub fn root(doc: *Node.Document, opts: RootOpts, writer: *std.Io.Writer, page: *Page) !void {
+pub fn root(doc: *Node.Document, opts: Opts, writer: *std.Io.Writer, page: *Page) !void {
     if (doc.is(Node.Document.HTMLDocument)) |html_doc| {
         blk: {
             // Ideally we just render the doctype which is part of the document
@@ -71,7 +70,7 @@ pub fn root(doc: *Node.Document, opts: RootOpts, writer: *std.Io.Writer, page: *
         }
     }
 
-    return deep(doc.asNode(), .{ .strip = opts.strip, .shadow = opts.shadow }, writer, page);
+    return deep(doc.asNode(), opts, writer, page);
 }
 
 pub fn deep(node: *Node, opts: Opts, writer: *std.Io.Writer, page: *Page) error{WriteFailed}!void {
@@ -83,19 +82,19 @@ fn _deep(node: *Node, opts: Opts, comptime force_slot: bool, writer: *std.Io.Wri
         .cdata => |cd| {
             if (node.is(Node.CData.Comment)) |_| {
                 try writer.writeAll("<!--");
-                try writer.writeAll(cd.getData());
+                try writer.writeAll(cd.getData().str());
                 try writer.writeAll("-->");
             } else if (node.is(Node.CData.ProcessingInstruction)) |pi| {
                 try writer.writeAll("<?");
                 try writer.writeAll(pi._target);
                 try writer.writeAll(" ");
-                try writer.writeAll(cd.getData());
+                try writer.writeAll(cd.getData().str());
                 try writer.writeAll("?>");
             } else {
                 if (shouldEscapeText(node._parent)) {
-                    try writeEscapedText(cd.getData(), writer);
+                    try writeEscapedText(cd.getData().str(), writer);
                 } else {
-                    try writer.writeAll(cd.getData());
+                    try writer.writeAll(cd.getData().str());
                 }
             }
         },
@@ -140,7 +139,24 @@ fn _deep(node: *Node, opts: Opts, comptime force_slot: bool, writer: *std.Io.Wri
                 }
             }
 
-            try children(node, opts, writer, page);
+            if (opts.with_frames and el.is(IFrame) != null) {
+                const frame = el.as(IFrame);
+                if (frame.getContentDocument()) |doc| {
+                    // A frame's document should always ahave a page, but
+                    // I'm not willing to crash a release build on that assertion.
+                    if (comptime IS_DEBUG) {
+                        std.debug.assert(doc._page != null);
+                    }
+                    if (doc._page) |frame_page| {
+                        try writer.writeByte('\n');
+                        root(doc, opts, writer, frame_page) catch return error.WriteFailed;
+                        try writer.writeByte('\n');
+                    }
+                }
+            } else {
+                try children(node, opts, writer, page);
+            }
+
             if (!isVoidElement(el)) {
                 try writer.writeAll("</");
                 try writer.writeAll(el.getTagNameDump());
@@ -172,7 +188,11 @@ fn _deep(node: *Node, opts: Opts, comptime force_slot: bool, writer: *std.Io.Wri
             try writer.writeAll(">\n");
         },
         .document_fragment => try children(node, opts, writer, page),
-        .attribute => unreachable,
+        .attribute => {
+            // Not called normally, but can be called via XMLSerializer.serializeToString
+            // in which case it should return an empty string
+            try writer.writeAll("");
+        },
     }
 }
 
@@ -294,6 +314,12 @@ fn shouldEscapeText(node_: ?*Node) bool {
     if (node.is(Node.Element.Html.Script) != null) {
         return false;
     }
+    // When scripting is enabled, <noscript> is a raw text element per the HTML spec
+    // (https://html.spec.whatwg.org/multipage/parsing.html#serialising-html-fragments).
+    // Its text content must not be HTML-escaped during serialization.
+    if (node.is(Node.Element.Html.Generic)) |generic| {
+        if (generic._tag == .noscript) return false;
+    }
     return true;
 }
 fn writeEscapedText(text: []const u8, writer: *std.Io.Writer) !void {

src/browser/js/Caller.zig

@@ -60,6 +60,11 @@ fn initWithContext(self: *Caller, ctx: *Context, v8_context: *const v8.Context)
     ctx.local = &self.local;
 }
 
+pub fn initFromHandle(self: *Caller, handle: ?*const v8.FunctionCallbackInfo) void {
+    const isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
+    self.init(isolate);
+}
+
 pub fn deinit(self: *Caller) void {
     const ctx = self.local.ctx;
     const call_depth = ctx.call_depth - 1;
@@ -251,7 +256,33 @@ fn _deleteNamedIndex(comptime T: type, local: *const Local, func: anytype, name:
     return handleIndexedReturn(T, F, false, local, ret, info, opts);
 }
 
-fn handleIndexedReturn(comptime T: type, comptime F: type, comptime getter: bool, local: *const Local, ret: anytype, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+pub fn getEnumerator(self: *Caller, comptime T: type, func: anytype, handle: *const v8.PropertyCallbackInfo, comptime opts: CallOpts) u8 {
+    const local = &self.local;
+
+    var hs: js.HandleScope = undefined;
+    hs.init(local.isolate);
+    defer hs.deinit();
+
+    const info = PropertyCallbackInfo{ .handle = handle };
+    return _getEnumerator(T, local, func, info, opts) catch |err| {
+        handleError(T, @TypeOf(func), local, err, info, opts);
+        // not intercepted
+        return 0;
+    };
+}
+
+fn _getEnumerator(comptime T: type, local: *const Local, func: anytype, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+    const F = @TypeOf(func);
+    var args: ParameterTypes(F) = undefined;
+    @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
+    if (@typeInfo(F).@"fn".params.len == 2) {
+        @field(args, "1") = local.ctx.page;
+    }
+    const ret = @call(.auto, func, args);
+    return handleIndexedReturn(T, F, true, local, ret, info, opts);
+}
+
+fn handleIndexedReturn(comptime T: type, comptime F: type, comptime with_value: bool, local: *const Local, ret: anytype, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
     // need to unwrap this error immediately for when opts.null_as_undefined == true
     // and we need to compare it to null;
     const non_error_ret = switch (@typeInfo(@TypeOf(ret))) {
@@ -274,7 +305,7 @@ fn handleIndexedReturn(comptime T: type, comptime F: type, comptime getter: bool
         else => ret,
     };
 
-    if (comptime getter) {
+    if (comptime with_value) {
         info.getReturnValue().set(try local.zigValueToJs(non_error_ret, opts));
     }
     // intercepted
@@ -302,15 +333,20 @@ fn nameToString(local: *const Local, comptime T: type, name: *const v8.Name) !T
 fn handleError(comptime T: type, comptime F: type, local: *const Local, err: anyerror, info: anytype, comptime opts: CallOpts) void {
     const isolate = local.isolate;
 
-    if (comptime @import("builtin").mode == .Debug and @TypeOf(info) == FunctionCallbackInfo) {
-        if (log.enabled(.js, .warn)) {
-            logFunctionCallError(local, @typeName(T), @typeName(F), err, info);
+    if (comptime IS_DEBUG and @TypeOf(info) == FunctionCallbackInfo) {
+        if (log.enabled(.js, .debug)) {
+            const DOMException = @import("../webapi/DOMException.zig");
+            if (DOMException.fromError(err) == null) {
+                // This isn't a DOMException, let's log it
+                logFunctionCallError(local, @typeName(T), @typeName(F), err, info);
+            }
         }
     }
 
     const js_err: *const v8.Value = switch (err) {
         error.TryCatchRethrow => return,
         error.InvalidArgument => isolate.createTypeError("invalid argument"),
+        error.TypeError => isolate.createTypeError(""),
         error.OutOfMemory => isolate.createError("out of memory"),
         error.IllegalConstructor => isolate.createError("Illegal Contructor"),
         else => blk: {
@@ -333,7 +369,7 @@ fn handleError(comptime T: type, comptime F: type, local: *const Local, err: any
 // this can add as much as 10 seconds of compilation time.
 fn logFunctionCallError(local: *const Local, type_name: []const u8, func: []const u8, err: anyerror, info: FunctionCallbackInfo) void {
     const args_dump = serializeFunctionArgs(local, info) catch "failed to serialize args";
-    log.info(.js, "function call error", .{
+    log.debug(.js, "function call error", .{
         .type = type_name,
         .func = func,
         .err = err,
@@ -410,6 +446,11 @@ pub const FunctionCallbackInfo = struct {
         return .{ .local = local, .handle = v8.v8__FunctionCallbackInfo__INDEX(self.handle, @intCast(index)).? };
     }
 
+    pub fn getData(self: FunctionCallbackInfo) ?*anyopaque {
+        const data = v8.v8__FunctionCallbackInfo__Data(self.handle) orelse return null;
+        return v8.v8__External__Value(@ptrCast(data));
+    }
+
     pub fn getThis(self: FunctionCallbackInfo) *const v8.Object {
         return v8.v8__FunctionCallbackInfo__This(self.handle).?;
     }
@@ -462,11 +503,13 @@ const ReturnValue = struct {
 
 pub const Function = struct {
     pub const Opts = struct {
+        noop: bool = false,
         static: bool = false,
         dom_exception: bool = false,
         as_typed_array: bool = false,
         null_as_undefined: bool = false,
         cache: ?Caching = null,
+        embedded_receiver: bool = false,
 
         // We support two ways to cache a value directly into a v8::Object. The
         // difference between the two is like the difference between a Map
@@ -537,6 +580,9 @@ pub const Function = struct {
         var args: ParameterTypes(F) = undefined;
         if (comptime opts.static) {
             args = try getArgs(F, 0, local, info);
+        } else if (comptime opts.embedded_receiver) {
+            args = try getArgs(F, 1, local, info);
+            @field(args, "0") = @ptrCast(@alignCast(info.getData() orelse unreachable));
         } else {
             args = try getArgs(F, 1, local, info);
             @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());

src/browser/js/Context.zig

@@ -43,13 +43,13 @@ env: *Env,
 page: *Page,
 isolate: js.Isolate,
 
+// Per-context microtask queue for isolation between contexts
+microtask_queue: *v8.MicrotaskQueue,
+
 // The v8::Global<v8::Context>. When necessary, we can create a v8::Local<<v8::Context>>
 // from this, and we can free it when the context is done.
 handle: v8.Global,
 
-// True if the context is auto-entered,
-entered: bool,
-
 cpu_profiler: ?*v8.CpuProfiler = null,
 
 heap_profiler: ?*v8.HeapProfiler = null,
@@ -124,10 +124,6 @@ script_manager: ?*ScriptManager,
 // Our macrotasks
 scheduler: Scheduler,
 
-// Prevents us from enqueuing a microtask for this context while we're shutting
-// down.
-shutting_down: bool = false,
-
 unknown_properties: (if (IS_DEBUG) std.StringHashMapUnmanaged(UnknownPropertyStat) else void) = if (IS_DEBUG) .{} else {},
 
 const ModuleEntry = struct {
@@ -149,16 +145,11 @@ const ModuleEntry = struct {
 };
 
 pub fn fromC(c_context: *const v8.Context) *Context {
-    const data = v8.v8__Context__GetEmbedderData(c_context, 1).?;
-    const big_int = js.BigInt{ .handle = @ptrCast(data) };
-    return @ptrFromInt(big_int.getUint64());
+    return @ptrCast(@alignCast(v8.v8__Context__GetAlignedPointerFromEmbedderData(c_context, 1)));
 }
 
 pub fn fromIsolate(isolate: js.Isolate) *Context {
-    const v8_context = v8.v8__Isolate__GetCurrentContext(isolate.handle).?;
-    const data = v8.v8__Context__GetEmbedderData(v8_context, 1).?;
-    const big_int = js.BigInt{ .handle = @ptrCast(data) };
-    return @ptrFromInt(big_int.getUint64());
+    return fromC(v8.v8__Isolate__GetCurrentContext(isolate.handle).?);
 }
 
 pub fn deinit(self: *Context) void {
@@ -172,21 +163,15 @@ pub fn deinit(self: *Context) void {
             });
         }
     }
-    defer self.env.app.arena_pool.release(self.arena);
+
+    const env = self.env;
+    defer env.app.arena_pool.release(self.arena);
 
     var hs: js.HandleScope = undefined;
     const entered = self.enter(&hs);
     defer entered.exit();
 
-    // We might have microtasks in the isolate that refence this context. The
-    // only option we have is to run them. But a microtask could queue another
-    // microtask, so we set the shutting_down flag, so that any such microtask
-    // will be a noop (this isn't automatic, when v8 calls our microtask callback
-    // the first thing we'll check is if self.shutting_down == true).
-    self.shutting_down = true;
-    self.env.runMicrotasks();
-
-    // can release objects
+    // this can release objects
     self.scheduler.deinit();
 
     {
@@ -248,11 +233,12 @@ pub fn deinit(self: *Context) void {
         }
     }
 
-    if (self.entered) {
-        v8.v8__Context__Exit(@ptrCast(v8.v8__Global__Get(&self.handle, self.isolate.handle)));
-    }
-
     v8.v8__Global__Reset(&self.handle);
+    env.isolate.notifyContextDisposed();
+    // There can be other tasks associated with this context that we need to
+    // purge while the context is still alive.
+    _ = env.pumpMessageLoop();
+    v8.v8__MicrotaskQueue__DELETE(self.microtask_queue);
 }
 
 pub fn weakRef(self: *Context, obj: anytype) void {
@@ -333,11 +319,14 @@ pub fn localScope(self: *Context, ls: *js.Local.Scope) void {
     const isolate = self.isolate;
     js.HandleScope.init(&ls.handle_scope, isolate);
 
+    const local_v8_context: *const v8.Context = @ptrCast(v8.v8__Global__Get(&self.handle, isolate.handle));
+    v8.v8__Context__Enter(local_v8_context);
+
     // TODO: add and init ls.hs  for the handlescope
     ls.local = .{
         .ctx = self,
-        .handle = @ptrCast(v8.v8__Global__Get(&self.handle, isolate.handle)),
         .isolate = isolate,
+        .handle = local_v8_context,
         .call_arena = self.call_arena,
     };
 }
@@ -364,7 +353,6 @@ pub fn stringToPersistedFunction(self: *Context, str: []const u8) !js.Function.G
         extra = "(e)";
     }
     const full = try std.fmt.allocPrintSentinel(self.call_arena, "(function(e) {{ {s}{s} }})", .{ normalized, extra }, 0);
-
     const js_val = try ls.local.compileAndRun(full, null);
     if (!js_val.isFunction()) {
         return error.StringFunctionError;
@@ -612,9 +600,18 @@ pub fn dynamicModuleCallback(
         .isolate = self.isolate,
     };
 
-    const resource = js.String.toSliceZ(.{ .local = &local, .handle = resource_name.? }) catch |err| {
-        log.err(.app, "OOM", .{ .err = err, .src = "dynamicModuleCallback1" });
-        return @constCast((local.rejectPromise("Out of memory") catch return null).handle);
+    const resource = blk: {
+        const resource_value = js.Value{ .handle = resource_name.?, .local = &local };
+        if (resource_value.isNullOrUndefined()) {
+            // will only be null / undefined in extreme cases (e.g. WPT tests)
+            // where you're
+            break :blk self.page.base();
+        }
+
+        break :blk js.String.toSliceZ(.{ .local = &local, .handle = resource_name.? }) catch |err| {
+            log.err(.app, "OOM", .{ .err = err, .src = "dynamicModuleCallback1" });
+            return @constCast((local.rejectPromise("Out of memory") catch return null).handle);
+        };
     };
 
     const specifier = js.String.toSliceZ(.{ .local = &local, .handle = v8_specifier.? }) catch |err| {
@@ -789,9 +786,16 @@ fn _dynamicModuleCallback(self: *Context, specifier: [:0]const u8, referrer: []c
             entry.module_promise = try module_resolver.promise().persist();
         } else {
             // the module was loaded, but not evaluated, we _have_ to evaluate it now
+            if (status == .kUninstantiated) {
+                if (try mod.instantiate(resolveModuleCallback) == false) {
+                    _ = resolver.reject("module instantiation", local.newString("Module instantiation failed"));
+                    return promise;
+                }
+            }
+
             const evaluated = mod.evaluate() catch {
                 if (comptime IS_DEBUG) {
-                    std.debug.assert(status == .kErrored);
+                    std.debug.assert(mod.getStatus() == .kErrored);
                 }
                 _ = resolver.reject("module evaluation", local.newString("Module evaluation failed"));
                 return promise;
@@ -871,13 +875,12 @@ fn resolveDynamicModule(self: *Context, state: *DynamicModuleResolveState, modul
 
     const then_callback = newFunctionWithData(local, struct {
         pub fn callback(callback_handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-            const isolate = v8.v8__FunctionCallbackInfo__GetIsolate(callback_handle).?;
             var c: Caller = undefined;
-            c.init(isolate);
+            c.initFromHandle(callback_handle);
             defer c.deinit();
 
-            const info_data = v8.v8__FunctionCallbackInfo__Data(callback_handle).?;
-            const s: *DynamicModuleResolveState = @ptrCast(@alignCast(v8.v8__External__Value(@ptrCast(info_data))));
+            const info = Caller.FunctionCallbackInfo{ .handle = callback_handle.? };
+            const s: *DynamicModuleResolveState = @ptrCast(@alignCast(info.getData() orelse return));
 
             if (s.context_id != c.local.ctx.id) {
                 // The microtask is tied to the isolate, not the context
@@ -896,17 +899,15 @@ fn resolveDynamicModule(self: *Context, state: *DynamicModuleResolveState, modul
 
     const catch_callback = newFunctionWithData(local, struct {
         pub fn callback(callback_handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-            const isolate = v8.v8__FunctionCallbackInfo__GetIsolate(callback_handle).?;
             var c: Caller = undefined;
-            c.init(isolate);
+            c.initFromHandle(callback_handle);
             defer c.deinit();
 
-            const info_data = v8.v8__FunctionCallbackInfo__Data(callback_handle).?;
-            const s: *DynamicModuleResolveState = @ptrCast(@alignCast(v8.v8__External__Value(@ptrCast(info_data))));
+            const info = Caller.FunctionCallbackInfo{ .handle = callback_handle.? };
+            const s: *DynamicModuleResolveState = @ptrCast(@alignCast(info.getData() orelse return));
 
             const l = &c.local;
-            const ctx = l.ctx;
-            if (s.context_id != ctx.id) {
+            if (s.context_id != l.ctx.id) {
                 return;
             }
 
@@ -998,13 +999,10 @@ pub fn queueSlotchangeDelivery(self: *Context) !void {
 // But for these Context microtasks, we want to (a) make sure the context isn't
 // being shut down and (b) that it's entered.
 fn enqueueMicrotask(self: *Context, callback: anytype) void {
-    self.isolate.enqueueMicrotask(struct {
+    // Use context-specific microtask queue instead of isolate queue
+    v8.v8__MicrotaskQueue__EnqueueMicrotask(self.microtask_queue, self.isolate.handle, struct {
         fn run(data: ?*anyopaque) callconv(.c) void {
             const ctx: *Context = @ptrCast(@alignCast(data.?));
-            if (ctx.shutting_down) {
-                return;
-            }
-
             var hs: js.HandleScope = undefined;
             const entered = ctx.enter(&hs);
             defer entered.exit();
@@ -1013,11 +1011,19 @@ fn enqueueMicrotask(self: *Context, callback: anytype) void {
     }.run, self);
 }
 
+// There's an assumption here: the js.Function will be alive when microtasks are
+// run. If we're Env.runMicrotasks in all the places that we're supposed to, then
+// this should be safe (I think). In whatever HandleScope a microtask is enqueued,
+// PerformCheckpoint should be run. So the v8::Local<v8::Function> should remain
+// valid. If we have problems with this, a simple solution is to provide a Zig
+// wrapper for these callbacks which references a js.Function.Temp, on callback
+// it executes the function and then releases the global.
 pub fn queueMicrotaskFunc(self: *Context, cb: js.Function) void {
-    self.isolate.enqueueMicrotaskFunc(cb);
+    // Use context-specific microtask queue instead of isolate queue
+    v8.v8__MicrotaskQueue__EnqueueMicrotaskFunc(self.microtask_queue, self.isolate.handle, cb.handle);
 }
 
-pub fn createFinalizerCallback(self: *Context, global: v8.Global, ptr: *anyopaque, finalizerFn: *const fn (ptr: *anyopaque) void) !*FinalizerCallback {
+pub fn createFinalizerCallback(self: *Context, global: v8.Global, ptr: *anyopaque, finalizerFn: *const fn (ptr: *anyopaque, page: *Page) void) !*FinalizerCallback {
     const fc = try self.finalizer_callback_pool.create();
     fc.* = .{
         .ctx = self,
@@ -1037,10 +1043,10 @@ pub const FinalizerCallback = struct {
     ctx: *Context,
     ptr: *anyopaque,
     global: v8.Global,
-    finalizerFn: *const fn (ptr: *anyopaque) void,
+    finalizerFn: *const fn (ptr: *anyopaque, page: *Page) void,
 
     pub fn deinit(self: *FinalizerCallback) void {
-        self.finalizerFn(self.ptr);
+        self.finalizerFn(self.ptr, self.ctx.page);
         self.ctx.finalizer_callback_pool.destroy(self);
     }
 };

src/browser/js/Env.zig

@@ -62,7 +62,8 @@ platform: *const Platform,
 // the global isolate
 isolate: js.Isolate,
 
-contexts: std.ArrayList(*js.Context),
+contexts: [64]*Context,
+context_count: usize,
 
 // just kept around because we need to free it on deinit
 isolate_params: *v8.CreateParams,
@@ -85,6 +86,8 @@ inspector: ?*Inspector,
 // which an be created once per isolaet.
 private_symbols: PrivateSymbols,
 
+microtask_queues_are_running: bool,
+
 pub const InitOpts = struct {
     with_inspector: bool = false,
 };
@@ -175,8 +178,23 @@ pub fn init(app: *App, opts: InitOpts) !Env {
             .data = null,
             .flags = v8.kOnlyInterceptStrings | v8.kNonMasking,
         });
+        // I don't 100% understand this. We actually set this up in the snapshot,
+        // but for the global instance, it doesn't work. SetIndexedHandler and
+        // SetNamedHandler are set on the Instance template, and that's the key
+        // difference. The context has its own global instance, so we need to set
+        // these back up directly on it. There might be a better way to do this.
+        v8.v8__ObjectTemplate__SetIndexedHandler(global_template_local, &.{
+            .getter = Window.JsApi.index.getter,
+            .setter = null,
+            .query = null,
+            .deleter = null,
+            .enumerator = null,
+            .definer = null,
+            .descriptor = null,
+            .data = null,
+            .flags = 0,
+        });
         v8.v8__Eternal__New(isolate_handle, @ptrCast(global_template_local), &global_eternal);
-
         private_symbols = PrivateSymbols.init(isolate_handle);
     }
 
@@ -188,7 +206,8 @@ pub fn init(app: *App, opts: InitOpts) !Env {
     return .{
         .app = app,
         .context_id = 0,
-        .contexts = .empty,
+        .contexts = undefined,
+        .context_count = 0,
         .isolate = isolate,
         .platform = &app.platform,
         .templates = templates,
@@ -196,15 +215,16 @@ pub fn init(app: *App, opts: InitOpts) !Env {
         .inspector = inspector,
         .global_template = global_eternal,
         .private_symbols = private_symbols,
+        .microtask_queues_are_running = false,
         .eternal_function_templates = eternal_function_templates,
     };
 }
 
 pub fn deinit(self: *Env) void {
     if (comptime IS_DEBUG) {
-        std.debug.assert(self.contexts.items.len == 0);
+        std.debug.assert(self.context_count == 0);
     }
-    for (self.contexts.items) |ctx| {
+    for (self.contexts[0..self.context_count]) |ctx| {
         ctx.deinit();
     }
 
@@ -213,8 +233,6 @@ pub fn deinit(self: *Env) void {
         i.deinit(allocator);
     }
 
-    self.contexts.deinit(allocator);
-
     allocator.free(self.templates);
     allocator.free(self.eternal_function_templates);
     self.private_symbols.deinit();
@@ -225,7 +243,7 @@ pub fn deinit(self: *Env) void {
     allocator.destroy(self.isolate_params);
 }
 
-pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
+pub fn createContext(self: *Env, page: *Page) !*Context {
     const context_arena = try self.app.arena_pool.acquire();
     errdefer self.app.arena_pool.release(context_arena);
 
@@ -234,10 +252,19 @@ pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
     hs.init(isolate);
     defer hs.deinit();
 
+    // Create a per-context microtask queue for isolation
+    const microtask_queue = v8.v8__MicrotaskQueue__New(isolate.handle, v8.kExplicit).?;
+    errdefer v8.v8__MicrotaskQueue__DELETE(microtask_queue);
+
     // Get the global template that was created once per isolate
     const global_template: *const v8.ObjectTemplate = @ptrCast(@alignCast(v8.v8__Eternal__Get(&self.global_template, isolate.handle).?));
     v8.v8__ObjectTemplate__SetInternalFieldCount(global_template, comptime Snapshot.countInternalFields(Window.JsApi));
-    const v8_context = v8.v8__Context__New(isolate.handle, global_template, null).?;
+
+    const v8_context = v8.v8__Context__New__Config(isolate.handle, &.{
+        .global_template = global_template,
+        .global_object = null,
+        .microtask_queue = microtask_queue,
+    }).?;
 
     // Create the v8::Context and wrap it in a v8::Global
     var context_global: v8.Global = undefined;
@@ -264,13 +291,6 @@ pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
     var global_global: v8.Global = undefined;
     v8.v8__Global__New(isolate.handle, global_obj, &global_global);
 
-    if (enter) {
-        v8.v8__Context__Enter(v8_context);
-    }
-    errdefer if (enter) {
-        v8.v8__Context__Exit(v8_context);
-    };
-
     const context_id = self.context_id;
     self.context_id = context_id + 1;
 
@@ -279,12 +299,12 @@ pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
         .env = self,
         .page = page,
         .id = context_id,
-        .entered = enter,
         .isolate = isolate,
         .arena = context_arena,
         .handle = context_global,
         .templates = self.templates,
         .call_arena = page.call_arena,
+        .microtask_queue = microtask_queue,
         .script_manager = &page._script_manager,
         .scheduler = .init(context_arena),
         .finalizer_callback_pool = std.heap.MemoryPool(Context.FinalizerCallback).init(self.app.allocator),
@@ -293,17 +313,24 @@ pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
 
     // Store a pointer to our context inside the v8 context so that, given
     // a v8 context, we can get our context out
-    const data = isolate.initBigInt(@intFromPtr(context));
-    v8.v8__Context__SetEmbedderData(v8_context, 1, @ptrCast(data.handle));
+    v8.v8__Context__SetAlignedPointerInEmbedderData(v8_context, 1, @ptrCast(context));
+
+    const count = self.context_count;
+    if (count >= self.contexts.len) {
+        return error.TooManyContexts;
+    }
+    self.contexts[count] = context;
+    self.context_count = count + 1;
 
-    try self.contexts.append(self.app.allocator, context);
     return context;
 }
 
 pub fn destroyContext(self: *Env, context: *Context) void {
-    for (self.contexts.items, 0..) |ctx, i| {
+    for (self.contexts[0..self.context_count], 0..) |ctx, i| {
         if (ctx == context) {
-            _ = self.contexts.swapRemove(i);
+            // Swap with last element and decrement count
+            self.context_count -= 1;
+            self.contexts[i] = self.contexts[self.context_count];
             break;
         }
     } else {
@@ -321,16 +348,26 @@ pub fn destroyContext(self: *Env, context: *Context) void {
     }
 
     context.deinit();
-    isolate.notifyContextDisposed();
 }
 
-pub fn runMicrotasks(self: *const Env) void {
-    self.isolate.performMicrotasksCheckpoint();
+pub fn runMicrotasks(self: *Env) void {
+    if (self.microtask_queues_are_running == false) {
+        const v8_isolate = self.isolate.handle;
+
+        self.microtask_queues_are_running = true;
+        defer self.microtask_queues_are_running = false;
+
+        var i: usize = 0;
+        while (i < self.context_count) : (i += 1) {
+            const ctx = self.contexts[i];
+            v8.v8__MicrotaskQueue__PerformCheckpoint(ctx.microtask_queue, v8_isolate);
+        }
+    }
 }
 
 pub fn runMacrotasks(self: *Env) !?u64 {
     var ms_to_next_task: ?u64 = null;
-    for (self.contexts.items) |ctx| {
+    for (self.contexts[0..self.context_count]) |ctx| {
         if (comptime builtin.is_test == false) {
             // I hate this comptime check as much as you do. But we have tests
             // which rely on short execution before shutdown. In real world, it's
@@ -353,12 +390,31 @@ pub fn runMacrotasks(self: *Env) !?u64 {
     return ms_to_next_task;
 }
 
-pub fn pumpMessageLoop(self: *const Env) bool {
+pub fn pumpMessageLoop(self: *const Env) void {
     var hs: v8.HandleScope = undefined;
     v8.v8__HandleScope__CONSTRUCT(&hs, self.isolate.handle);
     defer v8.v8__HandleScope__DESTRUCT(&hs);
 
-    return v8.v8__Platform__PumpMessageLoop(self.platform.handle, self.isolate.handle, false);
+    const isolate = self.isolate.handle;
+    const platform = self.platform.handle;
+    while (v8.v8__Platform__PumpMessageLoop(platform, isolate, false)) {}
+}
+
+pub fn hasBackgroundTasks(self: *const Env) bool {
+    return v8.v8__Isolate__HasPendingBackgroundTasks(self.isolate.handle);
+}
+
+pub fn waitForBackgroundTasks(self: *Env) void {
+    var hs: v8.HandleScope = undefined;
+    v8.v8__HandleScope__CONSTRUCT(&hs, self.isolate.handle);
+    defer v8.v8__HandleScope__DESTRUCT(&hs);
+
+    const isolate = self.isolate.handle;
+    const platform = self.platform.handle;
+    while (v8.v8__Isolate__HasPendingBackgroundTasks(isolate)) {
+        _ = v8.v8__Platform__PumpMessageLoop(platform, isolate, true);
+        self.runMicrotasks();
+    }
 }
 
 pub fn runIdleTasks(self: *const Env) void {
@@ -414,6 +470,10 @@ pub fn dumpMemoryStats(self: *Env) void {
     , .{ stats.total_heap_size, stats.total_heap_size_executable, stats.total_physical_size, stats.total_available_size, stats.used_heap_size, stats.heap_size_limit, stats.malloced_memory, stats.external_memory, stats.peak_malloced_memory, stats.number_of_native_contexts, stats.number_of_detached_contexts, stats.total_global_handles_size, stats.used_global_handles_size, stats.does_zap_garbage });
 }
 
+pub fn terminate(self: *const Env) void {
+    v8.v8__Isolate__TerminateExecution(self.isolate.handle);
+}
+
 fn promiseRejectCallback(message_handle: v8.PromiseRejectMessage) callconv(.c) void {
     const promise_handle = v8.v8__PromiseRejectMessage__GetPromise(&message_handle).?;
     const v8_isolate = v8.v8__Object__GetIsolate(@ptrCast(promise_handle)).?;

src/browser/js/Inspector.zig

@@ -241,8 +241,6 @@ pub const Session = struct {
             msg.ptr,
             msg.len,
         );
-
-        v8.v8__Isolate__PerformMicrotaskCheckpoint(isolate);
     }
 
     // Gets a value by object ID regardless of which context it is in.

src/browser/js/Isolate.zig

@@ -41,18 +41,6 @@ pub fn exit(self: Isolate) void {
     v8.v8__Isolate__Exit(self.handle);
 }
 
-pub fn performMicrotasksCheckpoint(self: Isolate) void {
-    v8.v8__Isolate__PerformMicrotaskCheckpoint(self.handle);
-}
-
-pub fn enqueueMicrotask(self: Isolate, callback: anytype, data: anytype) void {
-    v8.v8__Isolate__EnqueueMicrotask(self.handle, callback, data);
-}
-
-pub fn enqueueMicrotaskFunc(self: Isolate, function: js.Function) void {
-    v8.v8__Isolate__EnqueueMicrotaskFunc(self.handle, function.handle);
-}
-
 pub fn lowMemoryNotification(self: Isolate) void {
     v8.v8__Isolate__LowMemoryNotification(self.handle);
 }

src/browser/js/Local.zig

@@ -17,6 +17,7 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const Page = @import("../Page.zig");
 const log = @import("../../log.zig");
 const string = @import("../../string.zig");
 
@@ -81,8 +82,28 @@ pub fn createTypedArray(self: *const Local, comptime array_type: js.ArrayType, s
     return .init(self, size);
 }
 
+pub fn newCallback(
+    self: *const Local,
+    callback: anytype,
+    data: anytype,
+) js.Function {
+    const external = self.isolate.createExternal(data);
+    const handle = v8.v8__Function__New__DEFAULT2(self.handle, struct {
+        fn wrap(info_handle: ?*const js.v8.FunctionCallbackInfo) callconv(.c) void {
+            Caller.Function.call(@TypeOf(data), info_handle.?, callback, .{ .embedded_receiver = true });
+        }
+    }.wrap, @ptrCast(external)).?;
+    return .{ .local = self, .handle = handle };
+}
+
+pub fn runMacrotasks(self: *const Local) void {
+    const env = self.ctx.env;
+    env.pumpMessageLoop();
+    env.runMicrotasks(); // macrotasks can cause microtasks to queue
+}
+
 pub fn runMicrotasks(self: *const Local) void {
-    self.isolate.performMicrotasksCheckpoint();
+    self.ctx.env.runMicrotasks();
 }
 
 // == Executors ==
@@ -216,7 +237,7 @@ pub fn mapZigInstanceToJs(self: *const Local, js_obj_handle: ?*const v8.Object,
                     try ctx.finalizer_callbacks.put(ctx.arena, @intFromPtr(resolved.ptr), fc);
                 }
 
-                conditionallyFlagHandoff(value);
+                conditionallyReference(value);
                 if (@hasDecl(JsApi.Meta, "weak")) {
                     if (comptime IS_DEBUG) {
                         std.debug.assert(JsApi.Meta.weak == true);
@@ -322,6 +343,7 @@ pub fn zigValueToJs(self: *const Local, value: anytype, comptime opts: CallOpts)
                 },
 
                 inline
+                js.Array,
                 js.Function,
                 js.Object,
                 js.Promise,
@@ -453,6 +475,13 @@ pub fn jsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !T {
                 return js_val;
             }
 
+            if (comptime o.child == js.NullableString) {
+                if (js_val.isUndefined()) {
+                    return null;
+                }
+                return .{ .value = try js_val.toStringSlice() };
+            }
+
             if (comptime o.child == js.Object) {
                 return js.Object{
                     .local = self,
@@ -1054,7 +1083,7 @@ const Resolved = struct {
     class_id: u16,
     prototype_chain: []const @import("TaggedOpaque.zig").PrototypeChainEntry,
     finalizer_from_v8: ?*const fn (handle: ?*const v8.WeakCallbackInfo) callconv(.c) void = null,
-    finalizer_from_zig: ?*const fn (ptr: *anyopaque) void = null,
+    finalizer_from_zig: ?*const fn (ptr: *anyopaque, page: *Page) void = null,
 };
 pub fn resolveValue(value: anytype) Resolved {
     const T = bridge.Struct(@TypeOf(value));
@@ -1093,14 +1122,14 @@ fn resolveT(comptime T: type, value: *anyopaque) Resolved {
     };
 }
 
-fn conditionallyFlagHandoff(value: anytype) void {
+fn conditionallyReference(value: anytype) void {
     const T = bridge.Struct(@TypeOf(value));
-    if (@hasField(T, "_v8_handoff")) {
-        value._v8_handoff = true;
+    if (@hasDecl(T, "acquireRef")) {
+        value.acquireRef();
         return;
     }
     if (@hasField(T, "_proto")) {
-        conditionallyFlagHandoff(value._proto);
+        conditionallyReference(value._proto);
     }
 }
 
@@ -1201,13 +1230,20 @@ fn _debugValue(self: *const Local, js_val: js.Value, seen: *std.AutoHashMapUnman
         gop.value_ptr.* = {};
     }
 
-    const names_arr = js_obj.getOwnPropertyNames();
-    const len = names_arr.len();
-
     if (depth > 20) {
         return writer.writeAll("...deeply nested object...");
     }
-    const own_len = js_obj.getOwnPropertyNames().len();
+
+    const names_arr = js_obj.getOwnPropertyNames() catch {
+        return writer.writeAll("...invalid object...");
+    };
+    const len = names_arr.len();
+
+    const own_len = blk: {
+        const own_names = js_obj.getOwnPropertyNames() catch break :blk 0;
+        break :blk own_names.len();
+    };
+
     if (own_len == 0) {
         const js_val_str = try js_val.toStringSlice();
         if (js_val_str.len > 2000) {
@@ -1326,6 +1362,7 @@ pub const Scope = struct {
     handle_scope: js.HandleScope,
 
     pub fn deinit(self: *Scope) void {
+        v8.v8__Context__Exit(self.local.handle);
         self.handle_scope.deinit();
     }
 

src/browser/js/Object.zig

@@ -129,8 +129,14 @@ pub fn isNullOrUndefined(self: Object) bool {
     return v8.v8__Value__IsNullOrUndefined(@ptrCast(self.handle));
 }
 
-pub fn getOwnPropertyNames(self: Object) js.Array {
-    const handle = v8.v8__Object__GetOwnPropertyNames(self.handle, self.local.handle).?;
+pub fn getOwnPropertyNames(self: Object) !js.Array {
+    const handle = v8.v8__Object__GetOwnPropertyNames(self.handle, self.local.handle) orelse {
+        // This is almost always a fatal error case. Either we're in some exception
+        // and things are messy, or we're shutting down, or someone has messed up
+        // the object (like some WPT tests do).
+        return error.TypeError;
+    };
+
     return .{
         .local = self.local,
         .handle = handle,
@@ -145,8 +151,11 @@ pub fn getPropertyNames(self: Object) js.Array {
     };
 }
 
-pub fn nameIterator(self: Object) NameIterator {
-    const handle = v8.v8__Object__GetPropertyNames(self.handle, self.local.handle).?;
+pub fn nameIterator(self: Object) !NameIterator {
+    const handle = v8.v8__Object__GetPropertyNames(self.handle, self.local.handle) orelse {
+        // see getOwnPropertyNames above
+        return error.TypeError;
+    };
     const count = v8.v8__Array__Length(handle);
 
     return .{

src/browser/js/Snapshot.zig

@@ -282,9 +282,13 @@ fn hasNamedIndexedGetter(comptime JsApi: type) bool {
 fn countExternalReferences() comptime_int {
     @setEvalBranchQuota(100_000);
 
-    // +1 for the illegal constructor callback
-    var count: comptime_int = 1;
-    var has_non_template_property: bool = false;
+    var count: comptime_int = 0;
+
+    // +1 for the illegal constructor callback shared by various types
+    count += 1;
+
+    // +1 for the noop function shared by various types
+    count += 1;
 
     inline for (JsApis) |JsApi| {
         // Constructor (only if explicit)
@@ -304,17 +308,18 @@ fn countExternalReferences() comptime_int {
             const T = @TypeOf(value);
             if (T == bridge.Accessor) {
                 count += 1; // getter
-                if (value.setter != null) count += 1; // setter
+                if (value.setter != null) {
+                    count += 1;
+                }
             } else if (T == bridge.Function) {
                 count += 1;
-            } else if (T == bridge.Property) {
-                if (value.template == false) {
-                    has_non_template_property = true;
-                }
             } else if (T == bridge.Iterator) {
                 count += 1;
             } else if (T == bridge.Indexed) {
                 count += 1;
+                if (value.enumerator != null) {
+                    count += 1;
+                }
             } else if (T == bridge.NamedIndexed) {
                 count += 1; // getter
                 if (value.setter != null) count += 1;
@@ -323,10 +328,6 @@ fn countExternalReferences() comptime_int {
         }
     }
 
-    if (has_non_template_property) {
-        count += 1;
-    }
-
     // In debug mode, add unknown property callbacks for types without NamedIndexed
     if (comptime IS_DEBUG) {
         inline for (JsApis) |JsApi| {
@@ -346,7 +347,8 @@ fn collectExternalReferences() [countExternalReferences()]isize {
     references[idx] = @bitCast(@intFromPtr(&illegalConstructorCallback));
     idx += 1;
 
-    var has_non_template_property = false;
+    references[idx] = @bitCast(@intFromPtr(&bridge.Function.noopFunction));
+    idx += 1;
 
     inline for (JsApis) |JsApi| {
         if (@hasDecl(JsApi, "constructor")) {
@@ -373,16 +375,16 @@ fn collectExternalReferences() [countExternalReferences()]isize {
             } else if (T == bridge.Function) {
                 references[idx] = @bitCast(@intFromPtr(value.func));
                 idx += 1;
-            } else if (T == bridge.Property) {
-                if (value.template == false) {
-                    has_non_template_property = true;
-                }
             } else if (T == bridge.Iterator) {
                 references[idx] = @bitCast(@intFromPtr(value.func));
                 idx += 1;
             } else if (T == bridge.Indexed) {
                 references[idx] = @bitCast(@intFromPtr(value.getter));
                 idx += 1;
+                if (value.enumerator) |enumerator| {
+                    references[idx] = @bitCast(@intFromPtr(enumerator));
+                    idx += 1;
+                }
             } else if (T == bridge.NamedIndexed) {
                 references[idx] = @bitCast(@intFromPtr(value.getter));
                 idx += 1;
@@ -398,11 +400,6 @@ fn collectExternalReferences() [countExternalReferences()]isize {
         }
     }
 
-    if (has_non_template_property) {
-        references[idx] = @bitCast(@intFromPtr(&bridge.Property.getter));
-        idx += 1;
-    }
-
     // In debug mode, collect unknown property callbacks for types without NamedIndexed
     if (comptime IS_DEBUG) {
         inline for (JsApis) |JsApi| {
@@ -486,8 +483,8 @@ pub fn countInternalFields(comptime JsApi: type) u8 {
 
 // Attaches JsApi members to the prototype template (normal case)
 fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.FunctionTemplate) void {
-    const target = v8.v8__FunctionTemplate__PrototypeTemplate(template);
     const instance = v8.v8__FunctionTemplate__InstanceTemplate(template);
+    const prototype = v8.v8__FunctionTemplate__PrototypeTemplate(template);
 
     const declarations = @typeInfo(JsApi).@"struct".decls;
     var has_named_index_getter = false;
@@ -505,14 +502,14 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                     if (value.static) {
                         v8.v8__Template__SetAccessorProperty__DEFAULT(@ptrCast(template), js_name, getter_callback);
                     } else {
-                        v8.v8__ObjectTemplate__SetAccessorProperty__DEFAULT(target, js_name, getter_callback);
+                        v8.v8__ObjectTemplate__SetAccessorProperty__DEFAULT(prototype, js_name, getter_callback);
                     }
                 } else {
                     if (comptime IS_DEBUG) {
                         std.debug.assert(value.static == false);
                     }
                     const setter_callback = @constCast(v8.v8__FunctionTemplate__New__Config(isolate, &.{ .callback = value.setter.? }).?);
-                    v8.v8__ObjectTemplate__SetAccessorProperty__DEFAULT2(target, js_name, getter_callback, setter_callback);
+                    v8.v8__ObjectTemplate__SetAccessorProperty__DEFAULT2(prototype, js_name, getter_callback, setter_callback);
                 }
             },
             bridge.Function => {
@@ -521,16 +518,16 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                 if (value.static) {
                     v8.v8__Template__Set(@ptrCast(template), js_name, @ptrCast(function_template), v8.None);
                 } else {
-                    v8.v8__Template__Set(@ptrCast(target), js_name, @ptrCast(function_template), v8.None);
+                    v8.v8__Template__Set(@ptrCast(prototype), js_name, @ptrCast(function_template), v8.None);
                 }
             },
             bridge.Indexed => {
                 var configuration: v8.IndexedPropertyHandlerConfiguration = .{
                     .getter = value.getter,
+                    .enumerator = value.enumerator,
                     .setter = null,
                     .query = null,
                     .deleter = null,
-                    .enumerator = null,
                     .definer = null,
                     .descriptor = null,
                     .data = null,
@@ -559,7 +556,7 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                     v8.v8__Symbol__GetAsyncIterator(isolate)
                 else
                     v8.v8__Symbol__GetIterator(isolate);
-                v8.v8__Template__Set(@ptrCast(target), js_name, @ptrCast(function_template), v8.None);
+                v8.v8__Template__Set(@ptrCast(prototype), js_name, @ptrCast(function_template), v8.None);
             },
             bridge.Property => {
                 const js_value = switch (value.value) {
@@ -568,22 +565,14 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                 };
                 const js_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
 
-                if (value.template == false) {
-                    // not defined on the template, only on the instance. This
-                    // is like an Accessor, but because the value is known at
-                    // compile time, we skip _a lot_ of code and quickly return
-                    // the hard-coded value
-                    const getter_callback = @constCast(v8.v8__FunctionTemplate__New__Config(isolate, &.{
-                        .callback = bridge.Property.getter,
-                        .data = js_value,
-                        .side_effect_type = v8.kSideEffectType_HasSideEffectToReceiver,
-                    }));
-                    v8.v8__ObjectTemplate__SetAccessorProperty__DEFAULT(target, js_name, getter_callback);
-                } else {
-                    // apply it both to the type itself
+                {
+                    const flags = if (value.readonly) v8.ReadOnly + v8.DontDelete else 0;
+                    v8.v8__Template__Set(@ptrCast(prototype), js_name, js_value, flags);
+                }
+
+                if (value.template) {
+                    // apply it both to the type itself (e.g. Node.Elem)
                     v8.v8__Template__Set(@ptrCast(template), js_name, js_value, v8.ReadOnly + v8.DontDelete);
-                    // and to instances of the type
-                    v8.v8__Template__Set(@ptrCast(target), js_name, js_value, v8.ReadOnly + v8.DontDelete);
                 }
             },
             bridge.Constructor => {}, // already handled in generateConstructor

src/browser/js/TryCatch.zig

@@ -134,4 +134,17 @@ pub const Caught = struct {
         try writer.write(prefix ++ ".line", self.line);
         try writer.write(prefix ++ ".caught", self.caught);
     }
+
+    pub fn jsonStringify(self: Caught, jw: anytype) !void {
+        try jw.beginObject();
+        try jw.objectField("exception");
+        try jw.write(self.exception);
+        try jw.objectField("stack");
+        try jw.write(self.stack);
+        try jw.objectField("line");
+        try jw.write(self.line);
+        try jw.objectField("caught");
+        try jw.write(self.caught);
+        try jw.endObject();
+    }
 };

src/browser/js/bridge.zig

@@ -46,8 +46,8 @@ pub fn Builder(comptime T: type) type {
             return Function.init(T, func, opts);
         }
 
-        pub fn indexed(comptime getter_func: anytype, comptime opts: Indexed.Opts) Indexed {
-            return Indexed.init(T, getter_func, opts);
+        pub fn indexed(comptime getter_func: anytype, comptime enumerator_func: anytype, comptime opts: Indexed.Opts) Indexed {
+            return Indexed.init(T, getter_func, enumerator_func, opts);
         }
 
         pub fn namedIndexed(comptime getter_func: anytype, setter_func: anytype, deleter_func: anytype, comptime opts: NamedIndexed.Opts) NamedIndexed {
@@ -104,11 +104,11 @@ pub fn Builder(comptime T: type) type {
             return entries;
         }
 
-        pub fn finalizer(comptime func: *const fn (self: *T, shutdown: bool) void) Finalizer {
+        pub fn finalizer(comptime func: *const fn (self: *T, shutdown: bool, page: *Page) void) Finalizer {
             return .{
                 .from_zig = struct {
-                    fn wrap(ptr: *anyopaque) void {
-                        func(@ptrCast(@alignCast(ptr)), true);
+                    fn wrap(ptr: *anyopaque, page: *Page) void {
+                        func(@ptrCast(@alignCast(ptr)), true, page);
                     }
                 }.wrap,
 
@@ -120,7 +120,7 @@ pub fn Builder(comptime T: type) type {
                         const ctx = fc.ctx;
                         const value_ptr = fc.ptr;
                         if (ctx.finalizer_callbacks.contains(@intFromPtr(value_ptr))) {
-                            func(@ptrCast(@alignCast(value_ptr)), false);
+                            func(@ptrCast(@alignCast(value_ptr)), false, ctx.page);
                             ctx.release(value_ptr);
                         } else {
                             // A bit weird, but v8 _requires_ that we release it
@@ -160,6 +160,7 @@ pub const Constructor = struct {
 pub const Function = struct {
     static: bool,
     arity: usize,
+    noop: bool = false,
     cache: ?Caller.Function.Opts.Caching = null,
     func: *const fn (?*const v8.FunctionCallbackInfo) callconv(.c) void,
 
@@ -168,7 +169,7 @@ pub const Function = struct {
             .cache = opts.cache,
             .static = opts.static,
             .arity = getArity(@TypeOf(func)),
-            .func = struct {
+            .func = if (opts.noop) noopFunction else struct {
                 fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
                     Caller.Function.call(T, handle.?, func, opts);
                 }
@@ -176,6 +177,8 @@ pub const Function = struct {
         };
     }
 
+    pub fn noopFunction(_: ?*const v8.FunctionCallbackInfo) callconv(.c) void {}
+
     fn getArity(comptime T: type) usize {
         var count: usize = 0;
         var params = @typeInfo(T).@"fn".params;
@@ -227,26 +230,44 @@ pub const Accessor = struct {
 
 pub const Indexed = struct {
     getter: *const fn (idx: u32, handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8,
+    enumerator: ?*const fn (handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8,
 
     const Opts = struct {
         as_typed_array: bool = false,
         null_as_undefined: bool = false,
     };
 
-    fn init(comptime T: type, comptime getter: anytype, comptime opts: Opts) Indexed {
-        return .{ .getter = struct {
-            fn wrap(idx: u32, handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
-                const v8_isolate = v8.v8__PropertyCallbackInfo__GetIsolate(handle).?;
-                var caller: Caller = undefined;
-                caller.init(v8_isolate);
-                defer caller.deinit();
+    fn init(comptime T: type, comptime getter: anytype, comptime enumerator: anytype, comptime opts: Opts) Indexed {
+        var indexed = Indexed{
+            .enumerator = null,
+            .getter = struct {
+                fn wrap(idx: u32, handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
+                    const v8_isolate = v8.v8__PropertyCallbackInfo__GetIsolate(handle).?;
+                    var caller: Caller = undefined;
+                    caller.init(v8_isolate);
+                    defer caller.deinit();
 
-                return caller.getIndex(T, getter, idx, handle.?, .{
-                    .as_typed_array = opts.as_typed_array,
-                    .null_as_undefined = opts.null_as_undefined,
-                });
-            }
-        }.wrap };
+                    return caller.getIndex(T, getter, idx, handle.?, .{
+                        .as_typed_array = opts.as_typed_array,
+                        .null_as_undefined = opts.null_as_undefined,
+                    });
+                }
+            }.wrap,
+        };
+
+        if (@typeInfo(@TypeOf(enumerator)) != .null) {
+            indexed.enumerator = struct {
+                fn wrap(handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
+                    const v8_isolate = v8.v8__PropertyCallbackInfo__GetIsolate(handle).?;
+                    var caller: Caller = undefined;
+                    caller.init(v8_isolate);
+                    defer caller.deinit();
+                    return caller.getEnumerator(T, enumerator, handle.?, .{});
+                }
+            }.wrap;
+        }
+
+        return indexed;
     }
 };
 
@@ -367,6 +388,7 @@ pub const Callable = struct {
 pub const Property = struct {
     value: Value,
     template: bool,
+    readonly: bool,
 
     const Value = union(enum) {
         null,
@@ -378,27 +400,22 @@ pub const Property = struct {
 
     const Opts = struct {
         template: bool,
+        readonly: bool = true,
     };
 
     fn init(value: Value, opts: Opts) Property {
         return .{
             .value = value,
             .template = opts.template,
+            .readonly = opts.readonly,
         };
     }
-
-    pub fn getter(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-        const value = v8.v8__FunctionCallbackInfo__Data(handle.?);
-        var rv: v8.ReturnValue = undefined;
-        v8.v8__FunctionCallbackInfo__GetReturnValue(handle.?, &rv);
-        v8.v8__ReturnValue__Set(rv, value);
-    }
 };
 
 const Finalizer = struct {
     // The finalizer wrapper when called fro Zig. This is only called on
     // Context.deinit
-    from_zig: *const fn (ctx: *anyopaque) void,
+    from_zig: *const fn (ctx: *anyopaque, page: *Page) void,
 
     // The finalizer wrapper when called from V8. This may never be called
     // (hence why we fallback to calling in Context.denit). If it is called,
@@ -713,6 +730,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/css/CSSStyleRule.zig"),
     @import("../webapi/css/CSSStyleSheet.zig"),
     @import("../webapi/css/CSSStyleProperties.zig"),
+    @import("../webapi/css/FontFaceSet.zig"),
     @import("../webapi/css/MediaQueryList.zig"),
     @import("../webapi/css/StyleSheetList.zig"),
     @import("../webapi/Document.zig"),
@@ -749,6 +767,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/element/html/Custom.zig"),
     @import("../webapi/element/html/Data.zig"),
     @import("../webapi/element/html/DataList.zig"),
+    @import("../webapi/element/html/Details.zig"),
     @import("../webapi/element/html/Dialog.zig"),
     @import("../webapi/element/html/Directory.zig"),
     @import("../webapi/element/html/DList.zig"),
@@ -808,6 +827,8 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/element/svg/Generic.zig"),
     @import("../webapi/encoding/TextDecoder.zig"),
     @import("../webapi/encoding/TextEncoder.zig"),
+    @import("../webapi/encoding/TextEncoderStream.zig"),
+    @import("../webapi/encoding/TextDecoderStream.zig"),
     @import("../webapi/Event.zig"),
     @import("../webapi/event/CompositionEvent.zig"),
     @import("../webapi/event/CustomEvent.zig"),
@@ -844,6 +865,10 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/streams/ReadableStream.zig"),
     @import("../webapi/streams/ReadableStreamDefaultReader.zig"),
     @import("../webapi/streams/ReadableStreamDefaultController.zig"),
+    @import("../webapi/streams/WritableStream.zig"),
+    @import("../webapi/streams/WritableStreamDefaultWriter.zig"),
+    @import("../webapi/streams/WritableStreamDefaultController.zig"),
+    @import("../webapi/streams/TransformStream.zig"),
     @import("../webapi/Node.zig"),
     @import("../webapi/storage/storage.zig"),
     @import("../webapi/URL.zig"),
@@ -857,6 +882,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/IdleDeadline.zig"),
     @import("../webapi/Blob.zig"),
     @import("../webapi/File.zig"),
+    @import("../webapi/FileReader.zig"),
     @import("../webapi/Screen.zig"),
     @import("../webapi/VisualViewport.zig"),
     @import("../webapi/PerformanceObserver.zig"),
@@ -865,6 +891,8 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/navigation/NavigationActivation.zig"),
     @import("../webapi/canvas/CanvasRenderingContext2D.zig"),
     @import("../webapi/canvas/WebGLRenderingContext.zig"),
+    @import("../webapi/canvas/OffscreenCanvas.zig"),
+    @import("../webapi/canvas/OffscreenCanvasRenderingContext2D.zig"),
     @import("../webapi/SubtleCrypto.zig"),
     @import("../webapi/Selection.zig"),
     @import("../webapi/ImageData.zig"),

src/browser/js/js.zig

@@ -168,6 +168,16 @@ pub fn ArrayBufferRef(comptime kind: ArrayType) type {
     };
 }
 
+// If a WebAPI takes a []const u8, then we'll coerce any JS value to that string
+// so null -> "null". But if a WebAPI takes an optional string, ?[]const u8,
+// how should we handle null? If the parameter _isn't_ passed, then it's obvious
+// that it should be null, but what if `null` is passed? It's ambiguous, should
+// that be null, or "null"? It could depend on the api. So, `null` passed to
+// ?[]const u8 will be `null`. If you want it to be "null", use a `.js.NullableString`.
+pub const NullableString = struct {
+    value: []const u8,
+};
+
 pub const Exception = struct {
     local: *const Local,
     handle: *const v8.Value,

src/browser/markdown.zig

@@ -19,6 +19,7 @@
 const std = @import("std");
 
 const Page = @import("Page.zig");
+const CData = @import("webapi/CData.zig");
 const Element = @import("webapi/Element.zig");
 const Node = @import("webapi/Node.zig");
 
@@ -35,7 +36,6 @@ const State = struct {
 
     list_depth: usize = 0,
     list_stack: [32]ListState = undefined,
-    in_pre: bool = false,
     pre_node: ?*Node = null,
     in_code: bool = false,
     in_table: bool = false,
@@ -46,7 +46,7 @@ const State = struct {
 
 fn isBlock(tag: Element.Tag) bool {
     return switch (tag) {
-        .p, .div, .section, .article, .header, .footer, .nav, .aside, .h1, .h2, .h3, .h4, .h5, .h6, .ul, .ol, .blockquote, .pre, .table, .hr => true,
+        .p, .div, .section, .article, .main, .header, .footer, .nav, .aside, .h1, .h2, .h3, .h4, .h5, .h6, .ul, .ol, .blockquote, .pre, .table, .hr => true,
         else => false,
     };
 }
@@ -58,6 +58,67 @@ fn shouldAddSpacing(tag: Element.Tag) bool {
     };
 }
 
+fn isLayoutBlock(tag: Element.Tag) bool {
+    return switch (tag) {
+        .main, .section, .article, .nav, .aside, .header, .footer, .div, .ul, .ol => true,
+        else => false,
+    };
+}
+
+fn isStandaloneAnchor(el: *Element) bool {
+    const node = el.asNode();
+    const parent = node.parentNode() orelse return false;
+    const parent_el = parent.is(Element) orelse return false;
+
+    if (!isLayoutBlock(parent_el.getTag())) return false;
+
+    var prev = node.previousSibling();
+    while (prev) |p| : (prev = p.previousSibling()) {
+        if (isSignificantText(p)) return false;
+        if (p.is(Element)) |pe| {
+            if (isVisibleElement(pe)) break;
+        }
+    }
+
+    var next = node.nextSibling();
+    while (next) |n| : (next = n.nextSibling()) {
+        if (isSignificantText(n)) return false;
+        if (n.is(Element)) |ne| {
+            if (isVisibleElement(ne)) break;
+        }
+    }
+
+    return true;
+}
+
+fn isSignificantText(node: *Node) bool {
+    const text = node.is(Node.CData.Text) orelse return false;
+    return !isAllWhitespace(text.getWholeText());
+}
+
+fn isVisibleElement(el: *Element) bool {
+    return switch (el.getTag()) {
+        .script, .style, .noscript, .template, .head, .meta, .link, .title, .svg => false,
+        else => true,
+    };
+}
+
+fn isAllWhitespace(text: []const u8) bool {
+    return for (text) |c| {
+        if (!std.ascii.isWhitespace(c)) break false;
+    } else true;
+}
+
+fn hasBlockDescendant(node: *Node) bool {
+    var it = node.childrenIterator();
+    return while (it.next()) |child| {
+        if (child.is(Element)) |el| {
+            if (isBlock(el.getTag())) break true;
+            if (hasBlockDescendant(child)) break true;
+        }
+    } else false;
+}
+
 fn ensureNewline(state: *State, writer: *std.Io.Writer) !void {
     if (!state.last_char_was_newline) {
         try writer.writeByte('\n');
@@ -84,18 +145,16 @@ fn render(node: *Node, state: *State, writer: *std.Io.Writer, page: *Page) error
         },
         .cdata => |cd| {
             if (node.is(Node.CData.Text)) |_| {
-                var text = cd.getData();
-                if (state.in_pre) {
-                    if (state.pre_node) |pre| {
-                        if (node.parentNode() == pre and node.nextSibling() == null) {
-                            text = std.mem.trimRight(u8, text, " \t\r\n");
-                        }
+                var text = cd.getData().str();
+                if (state.pre_node) |pre| {
+                    if (node.parentNode() == pre and node.nextSibling() == null) {
+                        text = std.mem.trimRight(u8, text, " \t\r\n");
                     }
                 }
                 try renderText(text, state, writer);
             }
         },
-        else => {}, // Ignore other node types
+        else => {},
     }
 }
 
@@ -109,22 +168,15 @@ fn renderChildren(parent: *Node, state: *State, writer: *std.Io.Writer, page: *P
 fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Page) !void {
     const tag = el.getTag();
 
-    // Skip hidden/metadata elements
-    switch (tag) {
-        .script, .style, .noscript, .template, .head, .meta, .link, .title, .svg => return,
-        else => {},
-    }
+    if (!isVisibleElement(el)) return;
 
     // --- Opening Tag Logic ---
 
     // Ensure block elements start on a new line (double newline for paragraphs etc)
-    if (isBlock(tag)) {
-        if (!state.in_table) {
-            try ensureNewline(state, writer);
-            if (shouldAddSpacing(tag)) {
-                // Add an extra newline for spacing between blocks
-                try writer.writeByte('\n');
-            }
+    if (isBlock(tag) and !state.in_table) {
+        try ensureNewline(state, writer);
+        if (shouldAddSpacing(tag)) {
+            try writer.writeByte('\n');
         }
     } else if (tag == .li or tag == .tr) {
         try ensureNewline(state, writer);
@@ -154,14 +206,10 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
             const indent = if (state.list_depth > 0) state.list_depth - 1 else 0;
             for (0..indent) |_| try writer.writeAll("  ");
 
-            if (state.list_depth > 0) {
+            if (state.list_depth > 0 and state.list_stack[state.list_depth - 1].type == .ordered) {
                 const current_list = &state.list_stack[state.list_depth - 1];
-                if (current_list.type == .ordered) {
-                    try writer.print("{d}. ", .{current_list.index});
-                    current_list.index += 1;
-                } else {
-                    try writer.writeAll("- ");
-                }
+                try writer.print("{d}. ", .{current_list.index});
+                current_list.index += 1;
             } else {
                 try writer.writeAll("- ");
             }
@@ -187,12 +235,11 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
         },
         .pre => {
             try writer.writeAll("```\n");
-            state.in_pre = true;
             state.pre_node = el.asNode();
             state.last_char_was_newline = true;
         },
         .code => {
-            if (!state.in_pre) {
+            if (state.pre_node == null) {
                 try writer.writeByte('`');
                 state.in_code = true;
                 state.last_char_was_newline = false;
@@ -213,7 +260,7 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
         .hr => {
             try writer.writeAll("---\n");
             state.last_char_was_newline = true;
-            return; // Void element
+            return;
         },
         .br => {
             if (state.in_table) {
@@ -222,7 +269,7 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
                 try writer.writeByte('\n');
                 state.last_char_was_newline = true;
             }
-            return; // Void element
+            return;
         },
         .img => {
             try writer.writeAll("![");
@@ -235,9 +282,35 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
             }
             try writer.writeAll(")");
             state.last_char_was_newline = false;
-            return; // Treat as void
+            return;
         },
         .anchor => {
+            const has_block = hasBlockDescendant(el.asNode());
+            if (has_block) {
+                try renderChildren(el.asNode(), state, writer, page);
+                if (el.getAttributeSafe(comptime .wrap("href"))) |href| {
+                    if (!state.last_char_was_newline) try writer.writeByte('\n');
+                    try writer.writeAll("([Link](");
+                    try writer.writeAll(href);
+                    try writer.writeAll("))\n");
+                    state.last_char_was_newline = true;
+                }
+                return;
+            }
+
+            if (isStandaloneAnchor(el)) {
+                if (!state.last_char_was_newline) try writer.writeByte('\n');
+                try writer.writeByte('[');
+                try renderChildren(el.asNode(), state, writer, page);
+                try writer.writeAll("](");
+                if (el.getAttributeSafe(comptime .wrap("href"))) |href| {
+                    try writer.writeAll(href);
+                }
+                try writer.writeAll(")\n");
+                state.last_char_was_newline = true;
+                return;
+            }
+
             try writer.writeByte('[');
             try renderChildren(el.asNode(), state, writer, page);
             try writer.writeAll("](");
@@ -249,15 +322,11 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
             return;
         },
         .input => {
-            if (el.getAttributeSafe(comptime .wrap("type"))) |type_attr| {
-                if (std.ascii.eqlIgnoreCase(type_attr, "checkbox")) {
-                    if (el.getAttributeSafe(comptime .wrap("checked"))) |_| {
-                        try writer.writeAll("[x] ");
-                    } else {
-                        try writer.writeAll("[ ] ");
-                    }
-                    state.last_char_was_newline = false;
-                }
+            const type_attr = el.getAttributeSafe(comptime .wrap("type")) orelse return;
+            if (std.ascii.eqlIgnoreCase(type_attr, "checkbox")) {
+                const checked = el.getAttributeSafe(comptime .wrap("checked")) != null;
+                try writer.writeAll(if (checked) "[x] " else "[ ] ");
+                state.last_char_was_newline = false;
             }
             return;
         },
@@ -276,12 +345,11 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
                 try writer.writeByte('\n');
             }
             try writer.writeAll("```\n");
-            state.in_pre = false;
             state.pre_node = null;
             state.last_char_was_newline = true;
         },
         .code => {
-            if (!state.in_pre) {
+            if (state.pre_node == null) {
                 try writer.writeByte('`');
                 state.in_code = false;
                 state.last_char_was_newline = false;
@@ -310,8 +378,7 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
             try writer.writeByte('\n');
             if (state.table_row_index == 0) {
                 try writer.writeByte('|');
-                var i: usize = 0;
-                while (i < state.table_col_count) : (i += 1) {
+                for (0..state.table_col_count) |_| {
                     try writer.writeAll("---|");
                 }
                 try writer.writeByte('\n');
@@ -328,32 +395,22 @@ fn renderElement(el: *Element, state: *State, writer: *std.Io.Writer, page: *Pag
     }
 
     // Post-block newlines
-    if (isBlock(tag)) {
-        if (!state.in_table) {
-            try ensureNewline(state, writer);
-        }
+    if (isBlock(tag) and !state.in_table) {
+        try ensureNewline(state, writer);
     }
 }
 
 fn renderText(text: []const u8, state: *State, writer: *std.Io.Writer) !void {
     if (text.len == 0) return;
 
-    if (state.in_pre) {
+    if (state.pre_node) |_| {
         try writer.writeAll(text);
-        if (text.len > 0 and text[text.len - 1] == '\n') {
-            state.last_char_was_newline = true;
-        } else {
-            state.last_char_was_newline = false;
-        }
+        state.last_char_was_newline = text[text.len - 1] == '\n';
         return;
     }
 
     // Check for pure whitespace
-    const is_all_whitespace = for (text) |c| {
-        if (!std.ascii.isWhitespace(c)) break false;
-    } else true;
-
-    if (is_all_whitespace) {
+    if (isAllWhitespace(text)) {
         if (!state.last_char_was_newline) {
             try writer.writeByte(' ');
         }
@@ -364,13 +421,7 @@ fn renderText(text: []const u8, state: *State, writer: *std.Io.Writer) !void {
     var it = std.mem.tokenizeAny(u8, text, " \t\n\r");
     var first = true;
     while (it.next()) |word| {
-        if (first) {
-            if (!state.last_char_was_newline) {
-                if (text.len > 0 and std.ascii.isWhitespace(text[0])) {
-                    try writer.writeByte(' ');
-                }
-            }
-        } else {
+        if (!first or (!state.last_char_was_newline and std.ascii.isWhitespace(text[0]))) {
             try writer.writeByte(' ');
         }
 
@@ -380,10 +431,8 @@ fn renderText(text: []const u8, state: *State, writer: *std.Io.Writer) !void {
     }
 
     // Handle trailing whitespace from the original text
-    if (!first and !state.last_char_was_newline) {
-        if (text.len > 0 and std.ascii.isWhitespace(text[text.len - 1])) {
-            try writer.writeByte(' ');
-        }
+    if (!first and !state.last_char_was_newline and std.ascii.isWhitespace(text[text.len - 1])) {
+        try writer.writeByte(' ');
     }
 }
 
@@ -415,35 +464,35 @@ fn testMarkdownHTML(html: []const u8, expected: []const u8) !void {
     try testing.expectString(expected, aw.written());
 }
 
-test "markdown: basic" {
+test "browser.markdown: basic" {
     try testMarkdownHTML("Hello world", "Hello world\n");
 }
 
-test "markdown: whitespace" {
+test "browser.markdown: whitespace" {
     try testMarkdownHTML("<span>A</span> <span>B</span>", "A B\n");
 }
 
-test "markdown: escaping" {
+test "browser.markdown: escaping" {
     try testMarkdownHTML("<p># Not a header</p>", "\n\\# Not a header\n");
 }
 
-test "markdown: strikethrough" {
+test "browser.markdown: strikethrough" {
     try testMarkdownHTML("<s>deleted</s>", "~~deleted~~\n");
 }
 
-test "markdown: task list" {
+test "browser.markdown: task list" {
     try testMarkdownHTML(
         \\<input type="checkbox" checked><input type="checkbox">
     , "[x] [ ] \n");
 }
 
-test "markdown: ordered list" {
+test "browser.markdown: ordered list" {
     try testMarkdownHTML(
         \\<ol><li>First</li><li>Second</li></ol>
     , "1. First\n2. Second\n");
 }
 
-test "markdown: table" {
+test "browser.markdown: table" {
     try testMarkdownHTML(
         \\<table><thead><tr><th>Head 1</th><th>Head 2</th></tr></thead>
         \\<tbody><tr><td>Cell 1</td><td>Cell 2</td></tr></tbody></table>
@@ -456,7 +505,7 @@ test "markdown: table" {
     );
 }
 
-test "markdown: nested lists" {
+test "browser.markdown: nested lists" {
     try testMarkdownHTML(
         \\<ul><li>Parent<ul><li>Child</li></ul></li></ul>
     ,
@@ -466,19 +515,19 @@ test "markdown: nested lists" {
     );
 }
 
-test "markdown: blockquote" {
+test "browser.markdown: blockquote" {
     try testMarkdownHTML("<blockquote>Hello world</blockquote>", "\n> Hello world\n");
 }
 
-test "markdown: links" {
+test "browser.markdown: links" {
     try testMarkdownHTML("<a href=\"https://lightpanda.io\">Lightpanda</a>", "[Lightpanda](https://lightpanda.io)\n");
 }
 
-test "markdown: images" {
+test "browser.markdown: images" {
     try testMarkdownHTML("<img src=\"logo.png\" alt=\"Logo\">", "![Logo](logo.png)\n");
 }
 
-test "markdown: headings" {
+test "browser.markdown: headings" {
     try testMarkdownHTML("<h1>Title</h1><h2>Subtitle</h2>",
         \\
         \\# Title
@@ -488,7 +537,7 @@ test "markdown: headings" {
     );
 }
 
-test "markdown: code" {
+test "browser.markdown: code" {
     try testMarkdownHTML(
         \\<p>Use git push</p>
         \\<pre><code>line 1
@@ -504,3 +553,55 @@ test "markdown: code" {
         \\
     );
 }
+
+test "browser.markdown: block link" {
+    try testMarkdownHTML(
+        \\<a href="https://example.com">
+        \\  <h3>Title</h3>
+        \\  <p>Description</p>
+        \\</a>
+    ,
+        \\
+        \\### Title
+        \\
+        \\Description
+        \\([Link](https://example.com))
+        \\
+    );
+}
+
+test "browser.markdown: inline link" {
+    try testMarkdownHTML(
+        \\<p>Visit <a href="https://example.com">Example</a>.</p>
+    ,
+        \\
+        \\Visit [Example](https://example.com).
+        \\
+    );
+}
+
+test "browser.markdown: standalone anchors" {
+    // Inside main, with whitespace between anchors -> treated as blocks
+    try testMarkdownHTML(
+        \\<main>
+        \\  <a href="1">Link 1</a>
+        \\  <a href="2">Link 2</a>
+        \\</main>
+    ,
+        \\[Link 1](1)
+        \\[Link 2](2)
+        \\
+    );
+}
+
+test "browser.markdown: mixed anchors in main" {
+    // Anchors surrounded by text should remain inline
+    try testMarkdownHTML(
+        \\<main>
+        \\  Welcome <a href="1">Link 1</a>.
+        \\</main>
+    ,
+        \\Welcome [Link 1](1). 
+        \\
+    );
+}

src/browser/tests/animation/animation.html

@@ -3,13 +3,67 @@
 
 <script id=animation>
   let a1 = document.createElement('div').animate(null, null);
-  testing.expectEqual('finished', a1.playState);
+  testing.expectEqual('idle', a1.playState);
 
   let cb = [];
-  a1.ready.then(() => { cb.push('ready') });
   a1.finished.then((x) => {
-    cb.push('finished');
+    cb.push(a1.playState);
     cb.push(x == a1);
   });
-  testing.eventually(() => testing.expectEqual(['finished', true], cb));
+  a1.ready.then(() => {
+    cb.push(a1.playState);
+    a1.play();
+    cb.push(a1.playState);
+  });
+  testing.eventually(() => testing.expectEqual(['idle', 'running', 'finished', true], cb));
+</script>
+
+<script id=startTime>
+  let a2 = document.createElement('div').animate(null, null);
+  // startTime defaults to null
+  testing.expectEqual(null, a2.startTime);
+  // startTime is settable
+  a2.startTime = 42.5;
+  testing.expectEqual(42.5, a2.startTime);
+  // startTime can be reset to null
+  a2.startTime = null;
+  testing.expectEqual(null, a2.startTime);
+</script>
+
+<script id=onfinish>
+  let a3 = document.createElement('div').animate(null, null);
+  // onfinish defaults to null
+  testing.expectEqual(null, a3.onfinish);
+
+  let calls = [];
+  // onfinish callback should be scheduled and called asynchronously
+  a3.onfinish = function() { calls.push('finish'); };
+  a3.play();
+  testing.eventually(() => testing.expectEqual(['finish'], calls));
+</script>
+
+<script id=pause>
+  let a4 = document.createElement('div').animate(null, null);
+  let cb4 = [];
+  a4.finished.then((x) => { cb4.push(a4.playState) });
+  a4.ready.then(() => {
+    a4.play();
+    cb4.push(a4.playState)
+    a4.pause();
+    cb4.push(a4.playState)
+  });
+  testing.eventually(() => testing.expectEqual(['running', 'paused'], cb4));
+</script>
+
+<script id=finish>
+  let a5 = document.createElement('div').animate(null, null);
+  testing.expectEqual('idle', a5.playState);
+
+  let cb5 = [];
+  a5.finished.then((x) => { cb5.push(a5.playState) });
+  a5.ready.then(() => {
+    cb5.push(a5.playState);
+    a5.play();
+  });
+  testing.eventually(() => testing.expectEqual(['idle', 'finished'], cb5));
 </script>

src/browser/tests/canvas/canvas_rendering_context_2d.html

@@ -33,3 +33,70 @@
   testing.expectEqual(ctx.fillStyle, "rgba(255, 0, 0, 0.06)");
 }
 </script>
+
+<script id="CanvasRenderingContext2D#createImageData(width, height)">
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("2d");
+
+  const imageData = ctx.createImageData(100, 200);
+  testing.expectEqual(true, imageData instanceof ImageData);
+  testing.expectEqual(imageData.width, 100);
+  testing.expectEqual(imageData.height, 200);
+  testing.expectEqual(imageData.data.length, 100 * 200 * 4);
+  testing.expectEqual(true, imageData.data instanceof Uint8ClampedArray);
+
+  // All pixels should be initialized to 0.
+  testing.expectEqual(imageData.data[0], 0);
+  testing.expectEqual(imageData.data[1], 0);
+  testing.expectEqual(imageData.data[2], 0);
+  testing.expectEqual(imageData.data[3], 0);
+}
+</script>
+
+<script id="CanvasRenderingContext2D#createImageData(imageData)">
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("2d");
+
+  const source = ctx.createImageData(50, 75);
+  const imageData = ctx.createImageData(source);
+  testing.expectEqual(true, imageData instanceof ImageData);
+  testing.expectEqual(imageData.width, 50);
+  testing.expectEqual(imageData.height, 75);
+  testing.expectEqual(imageData.data.length, 50 * 75 * 4);
+}
+</script>
+
+<script id="CanvasRenderingContext2D#putImageData">
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("2d");
+
+  const imageData = ctx.createImageData(10, 10);
+  testing.expectEqual(true, imageData instanceof ImageData);
+  // Modify some pixel data.
+  imageData.data[0] = 255;
+  imageData.data[1] = 0;
+  imageData.data[2] = 0;
+  imageData.data[3] = 255;
+
+  // putImageData should not throw.
+  ctx.putImageData(imageData, 0, 0);
+  ctx.putImageData(imageData, 10, 20);
+  // With dirty rect parameters.
+  ctx.putImageData(imageData, 0, 0, 0, 0, 5, 5);
+}
+</script>
+
+
+<script id="getter">
+{
+  const element = document.createElement("canvas");
+  const ctx = element.getContext("2d");
+  testing.expectEqual('10px sans-serif', ctx.font);
+  ctx.font = 'bold 48px serif'
+  testing.expectEqual('bold 48px serif', ctx.font);
+
+}
+</script>

src/browser/tests/canvas/offscreen_canvas.html

@@ -0,0 +1,64 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id=OffscreenCanvas>
+{
+  const canvas = new OffscreenCanvas(256, 256);
+  testing.expectEqual(true, canvas instanceof OffscreenCanvas);
+  testing.expectEqual(canvas.width, 256);
+  testing.expectEqual(canvas.height, 256);
+}
+</script>
+
+<script id=OffscreenCanvas#width>
+{
+  const canvas = new OffscreenCanvas(100, 200);
+  testing.expectEqual(canvas.width, 100);
+  canvas.width = 300;
+  testing.expectEqual(canvas.width, 300);
+}
+</script>
+
+<script id=OffscreenCanvas#height>
+{
+  const canvas = new OffscreenCanvas(100, 200);
+  testing.expectEqual(canvas.height, 200);
+  canvas.height = 400;
+  testing.expectEqual(canvas.height, 400);
+}
+</script>
+
+<script id=OffscreenCanvas#getContext>
+{
+  const canvas = new OffscreenCanvas(64, 64);
+  const ctx = canvas.getContext("2d");
+  testing.expectEqual(true, ctx instanceof OffscreenCanvasRenderingContext2D);
+  // We can't really test rendering but let's try to call it at least.
+  ctx.fillRect(0, 0, 10, 10);
+}
+</script>
+
+<script id=OffscreenCanvas#convertToBlob>
+{
+  const canvas = new OffscreenCanvas(64, 64);
+  const promise = canvas.convertToBlob();
+  testing.expectEqual(true, promise instanceof Promise);
+  // The promise should resolve to a Blob (even if empty)
+  promise.then(blob => {
+    testing.expectEqual(true, blob instanceof Blob);
+    testing.expectEqual(blob.size, 0); // Empty since no rendering
+  });
+}
+</script>
+
+<script id=HTMLCanvasElement#transferControlToOffscreen>
+{
+  const htmlCanvas = document.createElement("canvas");
+  htmlCanvas.width = 128;
+  htmlCanvas.height = 96;
+  const offscreen = htmlCanvas.transferControlToOffscreen();
+  testing.expectEqual(true, offscreen instanceof OffscreenCanvas);
+  testing.expectEqual(offscreen.width, 128);
+  testing.expectEqual(offscreen.height, 96);
+}
+</script>

src/browser/tests/cdata/comment.html

@@ -4,4 +4,6 @@
 <script id=comment>
   testing.expectEqual('', new Comment().data);
   testing.expectEqual('over 9000! ', new Comment('over 9000! ').data);
+
+  testing.expectEqual('null', new Comment(null).data);
 </script>

src/browser/tests/cdata/text.html

@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <a id="link" href="foo" class="ok">OK</a>
 
-<script src="../../testing.js"></script>
+<script src="../testing.js"></script>
 <script id=text>
   let t = new Text('foo');
   testing.expectEqual('foo', t.data);
@@ -16,4 +16,7 @@
   let split = text.splitText('OK'.length);
   testing.expectEqual(' modified', split.data);
   testing.expectEqual('OK', text.data);
+
+    let x = new Text(null);
+    testing.expectEqual("null", x.data);
 </script>

src/browser/tests/css.html

@@ -69,3 +69,11 @@
     testing.expectEqual(true, CSS.supports('z-index', '10'));
   }
 </script>
+
+<script id="escape_null_character">
+  {
+    testing.expectEqual('\uFFFD', CSS.escape('\x00'));
+    testing.expectEqual('test\uFFFDvalue', CSS.escape('test\x00value'));
+    testing.expectEqual('\uFFFDabc', CSS.escape('\x00abc'));
+  }
+</script>

src/browser/tests/css/font_face_set.html

@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id="document_fonts_exists">
+{
+    testing.expectTrue(document.fonts !== undefined);
+    testing.expectTrue(document.fonts !== null);
+}
+</script>
+
+<script id="document_fonts_same_instance">
+{
+    // Should return same instance each time
+    const f1 = document.fonts;
+    const f2 = document.fonts;
+    testing.expectTrue(f1 === f2);
+}
+</script>
+
+<script id="document_fonts_status">
+{
+    testing.expectEqual('loaded', document.fonts.status);
+}
+</script>
+
+<script id="document_fonts_size">
+{
+    testing.expectEqual(0, document.fonts.size);
+}
+</script>
+
+<script id="document_fonts_ready_is_promise">
+{
+    const ready = document.fonts.ready;
+    testing.expectTrue(ready instanceof Promise);
+}
+</script>
+
+<script id="document_fonts_ready_resolves">
+{
+    let resolved = false;
+    document.fonts.ready.then(() => { resolved = true; });
+    // Promise resolution is async; just confirm .then() does not throw
+    testing.expectTrue(typeof document.fonts.ready.then === 'function');
+}
+</script>
+
+<script id="document_fonts_check">
+{
+    testing.expectTrue(document.fonts.check('16px sans-serif'));
+}
+</script>
+
+<script id="document_fonts_constructor_name">
+{
+    testing.expectEqual('FontFaceSet', document.fonts.constructor.name);
+}
+</script>

src/browser/tests/css/stylesheet.html

@@ -205,3 +205,73 @@
     testing.expectEqual('', style.getPropertyPriority('content'));
 }
 </script>
+
+<script id="CSSStyleDeclaration_style_syncs_to_attribute">
+{
+    // JS style modifications must be reflected in getAttribute.
+    const div = document.createElement('div');
+
+    // Named property assignment (element.style.X = ...)
+    div.style.opacity = '0';
+    testing.expectEqual('opacity: 0;', div.getAttribute('style'));
+
+    // Update existing property
+    div.style.opacity = '1';
+    testing.expectEqual('opacity: 1;', div.getAttribute('style'));
+
+    // Add a second property
+    div.style.color = 'red';
+    testing.expectTrue(div.getAttribute('style').includes('opacity: 1'));
+    testing.expectTrue(div.getAttribute('style').includes('color: red'));
+
+    // removeProperty syncs back
+    div.style.removeProperty('opacity');
+    testing.expectTrue(!div.getAttribute('style').includes('opacity'));
+    testing.expectTrue(div.getAttribute('style').includes('color: red'));
+
+    // setCssText syncs back
+    div.style.cssText = 'filter: blur(0px)';
+    testing.expectEqual('filter: blur(0px);', div.getAttribute('style'));
+
+    // setCssText with empty string clears attribute
+    div.style.cssText = '';
+    testing.expectEqual('', div.getAttribute('style'));
+}
+</script>
+
+<script id="CSSStyleDeclaration_outerHTML_reflects_style_changes">
+{
+    // outerHTML must reflect JS-modified styles (regression test for
+    // DOM serialization reading stale HTML-parsed attribute values).
+    const div = document.createElement('div');
+    div.setAttribute('style', 'filter:blur(10px);opacity:0');
+
+    div.style.filter = 'blur(0px)';
+    div.style.opacity = '1';
+
+    const html = div.outerHTML;
+    testing.expectTrue(html.includes('filter: blur(0px)'));
+    testing.expectTrue(html.includes('opacity: 1'));
+    testing.expectTrue(!html.includes('blur(10px)'));
+    testing.expectTrue(!html.includes('opacity:0'));
+}
+</script>
+
+<script id="CSSStyleDeclaration_non_ascii_custom_property">
+{
+    // Regression test: accessing element.style must not crash when the inline
+    // style attribute contains CSS custom properties with non-ASCII (UTF-8
+    // multibyte) names, such as French accented characters.
+    // The CSS Tokenizer's consumeName() must advance over whole UTF-8 sequences
+    // rather than byte-by-byte to avoid landing on a continuation byte.
+    const div = document.createElement('div');
+    div.setAttribute('style',
+        '--color-store-bulles-\u00e9t\u00e9-fg: #6a818f;' +
+        '--color-store-soir\u00e9es-odl-fg: #56b3b3;' +
+        'color: red;'
+    );
+
+    // Must not crash, and ASCII properties that follow non-ASCII ones must be readable.
+    testing.expectEqual('red', div.style.getPropertyValue('color'));
+}
+</script>

src/browser/tests/custom_elements/constructor.html

@@ -53,3 +53,22 @@
     testing.expectEqual('NO-CONSTRUCTOR-ELEMENT', el.tagName);
 }
 </script>
+
+<div id=clone_container></div>
+
+<script id=clone>
+    {
+        let calls = 0;
+        class MyCloneElementA extends HTMLElement {
+            constructor() {
+                super();
+                calls += 1;
+                $('#clone_container').appendChild(this);
+            }
+        }
+        customElements.define('my-clone_element_a', MyCloneElementA);
+        const original = document.createElement('my-clone_element_a');
+         $('#clone_container').cloneNode(true);
+        testing.expectEqual(2, calls);
+    }
+</script>

src/browser/tests/document/create_element_ns.html

@@ -7,9 +7,11 @@
   testing.expectEqual(true, htmlDiv1 instanceof HTMLDivElement);
   testing.expectEqual('http://www.w3.org/1999/xhtml', htmlDiv1.namespaceURI);
 
+  // Per spec, createElementNS does NOT lowercase — 'DIV' != 'div', so this
+  // creates an HTMLUnknownElement, not an HTMLDivElement.
   const htmlDiv2 = document.createElementNS('http://www.w3.org/1999/xhtml', 'DIV');
   testing.expectEqual('DIV', htmlDiv2.tagName);
-  testing.expectEqual(true, htmlDiv2 instanceof HTMLDivElement);
+  testing.expectEqual(false, htmlDiv2 instanceof HTMLDivElement);
   testing.expectEqual('http://www.w3.org/1999/xhtml', htmlDiv2.namespaceURI);
 
   const svgRect = document.createElementNS('http://www.w3.org/2000/svg', 'RecT');

src/browser/tests/document/document.html

@@ -1,5 +1,6 @@
 <!DOCTYPE html>
 <head id="the_head">
+  <meta charset="UTF-8">
   <title>Test Document Title</title>
   <script src="../testing.js"></script>
 </head>
@@ -11,7 +12,7 @@
   testing.expectEqual(10, document.childNodes[0].nodeType);
   testing.expectEqual(null, document.parentNode);
   testing.expectEqual(undefined, document.getCurrentScript);
-  testing.expectEqual("http://127.0.0.1:9582/src/browser/tests/document/document.html", document.URL);
+  testing.expectEqual(testing.BASE_URL + 'document/document.html', document.URL);
   testing.expectEqual(window, document.defaultView);
   testing.expectEqual(false, document.hidden);
   testing.expectEqual("visible", document.visibilityState);
@@ -56,7 +57,7 @@
   testing.expectEqual('CSS1Compat', document.compatMode);
   testing.expectEqual(document.URL, document.documentURI);
   testing.expectEqual('', document.referrer);
-  testing.expectEqual('127.0.0.1', document.domain);
+  testing.expectEqual(testing.HOST, document.domain);
 </script>
 
 <script id=programmatic_document_metadata>
@@ -69,7 +70,7 @@
   testing.expectEqual('CSS1Compat', doc.compatMode);
   testing.expectEqual('', doc.referrer);
   // Programmatic document should have empty domain (no URL/origin)
-  testing.expectEqual('127.0.0.1', doc.domain);
+  testing.expectEqual(testing.HOST, doc.domain);
 </script>
 
 <!-- Test anchors and links -->
@@ -176,15 +177,111 @@
   testing.expectEqual(initialLength, anchors.length);
 </script>
 
-<script id=cookie>
-  testing.expectEqual('', document.cookie);
-  document.cookie = 'name=Oeschger;';
-  document.cookie = 'favorite_food=tripe;';
+<script id=cookie_basic>
+  // Basic cookie operations
+  document.cookie = 'testbasic1=Oeschger';
+  testing.expectEqual(true, document.cookie.includes('testbasic1=Oeschger'));
 
-  testing.expectEqual('name=Oeschger; favorite_food=tripe', document.cookie);
-  // "" should be returned, but the framework overrules it atm
+  document.cookie = 'testbasic2=tripe';
+  testing.expectEqual(true, document.cookie.includes('testbasic1=Oeschger'));
+  testing.expectEqual(true, document.cookie.includes('testbasic2=tripe'));
+
+  // HttpOnly should be ignored from JavaScript
+  const beforeHttp = document.cookie;
   document.cookie = 'IgnoreMy=Ghost; HttpOnly';
-  testing.expectEqual('name=Oeschger; favorite_food=tripe', document.cookie);
+  testing.expectEqual(false, document.cookie.includes('IgnoreMy=Ghost'));
+
+  // Clean up
+  document.cookie = 'testbasic1=; Max-Age=0';
+  document.cookie = 'testbasic2=; Max-Age=0';
+</script>
+
+<script id=cookie_special_chars>
+  // Test special characters in cookie values
+  document.cookie = 'testspaces=hello world';
+  testing.expectEqual(true, document.cookie.includes('testspaces=hello world'));
+  document.cookie = 'testspaces=; Max-Age=0';
+
+  // Test various allowed special characters
+  document.cookie = 'testspecial=!#$%&\'()*+-./';
+  testing.expectEqual(true, document.cookie.includes('testspecial='));
+  document.cookie = 'testspecial=; Max-Age=0';
+
+  // Semicolon terminates the cookie value
+  document.cookie = 'testsemi=before;after';
+  testing.expectEqual(true, document.cookie.includes('testsemi=before'));
+  testing.expectEqual(false, document.cookie.includes('after'));
+  document.cookie = 'testsemi=; Max-Age=0';
+</script>
+
+<script id=cookie_empty_name>
+  // Cookie with empty name (just a value)
+  document.cookie = 'teststandalone';
+  testing.expectEqual(true, document.cookie.includes('teststandalone'));
+  document.cookie = 'teststandalone; Max-Age=0';
+</script>
+
+<script id=cookie_whitespace>
+  // Names and values should be trimmed
+  document.cookie = '  testtrim  =  trimmed_value  ';
+  testing.expectEqual(true, document.cookie.includes('testtrim=trimmed_value'));
+  document.cookie = 'testtrim=; Max-Age=0';
+</script>
+
+<script id=cookie_max_age>
+  // Max-Age=0 should immediately delete
+  document.cookie = 'testtemp0=value; Max-Age=0';
+  testing.expectEqual(false, document.cookie.includes('testtemp0=value'));
+
+  // Negative Max-Age should also delete
+  document.cookie = 'testinstant=value';
+  testing.expectEqual(true, document.cookie.includes('testinstant=value'));
+  document.cookie = 'testinstant=value; Max-Age=-1';
+  testing.expectEqual(false, document.cookie.includes('testinstant=value'));
+
+  // Positive Max-Age should keep cookie
+  document.cookie = 'testkept=value; Max-Age=3600';
+  testing.expectEqual(true, document.cookie.includes('testkept=value'));
+  document.cookie = 'testkept=; Max-Age=0';
+</script>
+
+<script id=cookie_overwrite>
+  // Setting a cookie with the same name should overwrite
+  document.cookie = 'testoverwrite=first';
+  testing.expectEqual(true, document.cookie.includes('testoverwrite=first'));
+
+  document.cookie = 'testoverwrite=second';
+  testing.expectEqual(true, document.cookie.includes('testoverwrite=second'));
+  testing.expectEqual(false, document.cookie.includes('testoverwrite=first'));
+
+  document.cookie = 'testoverwrite=; Max-Age=0';
+</script>
+
+<script id=cookie_path>
+  // Path attribute
+  document.cookie = 'testpath1=value; Path=/';
+  testing.expectEqual(true, document.cookie.includes('testpath1=value'));
+
+  // Different path cookie should coexist
+  document.cookie = 'testpath2=value2; Path=/src';
+  testing.expectEqual(true, document.cookie.includes('testpath1=value'));
+
+  document.cookie = 'testpath1=; Max-Age=0; Path=/';
+  document.cookie = 'testpath2=; Max-Age=0; Path=/src';
+</script>
+
+<script id=cookie_invalid_chars>
+  // Control characters (< 32 or > 126) should be rejected
+  const beforeBad = document.cookie;
+
+  document.cookie = 'testbad1\x00=value';
+  testing.expectEqual(false, document.cookie.includes('testbad1'));
+
+  document.cookie = 'testbad2\x1F=value';
+  testing.expectEqual(false, document.cookie.includes('testbad2'));
+
+  document.cookie = 'testbad3=val\x7F';
+  testing.expectEqual(false, document.cookie.includes('testbad3'));
 </script>
 
 <script id=createAttribute>

src/browser/tests/document/focus.html

@@ -297,3 +297,25 @@
   testing.expectEqual(btn, document.activeElement);
 }
 </script>
+
+<script id="focus_disconnected_no_blur">
+{
+  const input1 = $('#input1');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  input1.focus();
+  testing.expectEqual(input1, document.activeElement);
+
+  let blurCount = 0;
+  input1.addEventListener('blur', () => { blurCount++ });
+
+  // Focusing a disconnected element should be a no-op:
+  // blur must not fire on the currently focused element
+  document.createElement('a').focus();
+  testing.expectEqual(input1, document.activeElement);
+  testing.expectEqual(0, blurCount);
+}
+</script>

src/browser/tests/document/query_selector_all.html

@@ -27,7 +27,9 @@
     testing.expectEqual(expected.length, result.length);
     testing.expectEqual(expected, Array.from(result).map((e) => e.textContent));
     testing.expectEqual(expected, Array.from(result.values()).map((e) => e.textContent));
+
     testing.expectEqual(expected.map((e, i) => i), Array.from(result.keys()));
+    testing.expectEqual(expected.map((e, i) => i.toString()), Object.keys(result));
   }
 </script>
 
@@ -376,3 +378,93 @@
 }
 </script>
 
+<form id="form-validity-test">
+  <input id="vi-required-empty" type="text" required>
+  <input id="vi-optional" type="text">
+  <input id="vi-hidden-required" type="hidden" required>
+  <fieldset id="vi-fieldset">
+    <input id="vi-nested-required" type="text" required>
+    <select id="vi-select-required" required>
+      <option value="">Pick one</option>
+      <option value="a">A</option>
+    </select>
+  </fieldset>
+</form>
+<input id="vi-checkbox" type="checkbox">
+
+<script id=invalidPseudo>
+{
+  // Inputs with required + empty value are :invalid
+  testing.expectEqual(true, document.getElementById('vi-required-empty').matches(':invalid'));
+  testing.expectEqual(false, document.getElementById('vi-required-empty').matches(':valid'));
+
+  // Inputs without required are :valid
+  testing.expectEqual(false, document.getElementById('vi-optional').matches(':invalid'));
+  testing.expectEqual(true, document.getElementById('vi-optional').matches(':valid'));
+
+  // hidden inputs are not candidates for constraint validation
+  testing.expectEqual(false, document.getElementById('vi-hidden-required').matches(':invalid'));
+  testing.expectEqual(false, document.getElementById('vi-hidden-required').matches(':valid'));
+
+  // select with required and empty selected value is :invalid
+  testing.expectEqual(true, document.getElementById('vi-select-required').matches(':invalid'));
+  testing.expectEqual(false, document.getElementById('vi-select-required').matches(':valid'));
+
+  // fieldset containing invalid controls is :invalid
+  testing.expectEqual(true, document.getElementById('vi-fieldset').matches(':invalid'));
+  testing.expectEqual(false, document.getElementById('vi-fieldset').matches(':valid'));
+
+  // form containing invalid controls is :invalid
+  testing.expectEqual(true, document.getElementById('form-validity-test').matches(':invalid'));
+  testing.expectEqual(false, document.getElementById('form-validity-test').matches(':valid'));
+}
+</script>
+
+<script id=validAfterValueSet>
+{
+  // After setting a value, a required input becomes :valid
+  const input = document.getElementById('vi-required-empty');
+  input.value = 'hello';
+  testing.expectEqual(false, input.matches(':invalid'));
+  testing.expectEqual(true, input.matches(':valid'));
+  input.value = '';
+}
+</script>
+
+<script id=indeterminatePseudo>
+{
+  const cb = document.getElementById('vi-checkbox');
+  testing.expectEqual(false, cb.matches(':indeterminate'));
+  cb.indeterminate = true;
+  testing.expectEqual(true, cb.matches(':indeterminate'));
+  cb.indeterminate = false;
+  testing.expectEqual(false, cb.matches(':indeterminate'));
+}
+</script>
+
+<script id=iterator_list_lifetime>
+  // This test is intended to ensure that a list remains alive as long as it
+  // must, i.e. as long as any iterator referencing the list is alive.
+  // This test depends on being able to force the v8 GC to cleanup, which
+  // we have no way of controlling. At worst, the test will pass without
+  // actually testing correct lifetime. But it was at least manually verified
+  // for me that this triggers plenty of GCs.
+  const expected = Array.from(document.querySelectorAll('*')).length;
+  {
+    let keys = [];
+
+    // Phase 1: Create many lists+iterators to fill up the arena pool
+    for (let i = 0; i < 1000; i++) {
+      let list = document.querySelectorAll('*');
+      keys.push(list.keys());
+
+      // Create an Event every iteration to compete for arenas
+      new Event('arena_compete');
+    }
+
+    for (let k of keys) {
+      const result = Array.from(k);
+      testing.expectEqual(expected, result.length);
+    }
+  }
+</script>

src/browser/tests/document/query_selector_attributes.html

@@ -111,3 +111,15 @@
   const containerDataTest = document.querySelector('#container [data-test]');
   testing.expectEqual('First', containerDataTest.innerText);
 </script>
+
+<link rel="preload" as="image" imagesrcset="url1.png 1x, url2.png 2x" id="preload-link">
+
+<script id="commaInAttrValue">
+  // Commas inside quoted attribute values must not be treated as selector separators
+  const el = document.querySelector('link[rel="preload"][as="image"][imagesrcset="url1.png 1x, url2.png 2x"]');
+  testing.expectEqual('preload-link', el.id);
+
+  // Also test with single quotes inside selector
+  const el2 = document.querySelector("link[imagesrcset='url1.png 1x, url2.png 2x']");
+  testing.expectEqual('preload-link', el2.id);
+</script>

src/browser/tests/domimplementation.html

@@ -108,6 +108,20 @@
   }
 </script>
 
+<script id=createHTMLDocument_nulll_title>
+  {
+    const impl = document.implementation;
+    const doc = impl.createHTMLDocument(null);
+
+    testing.expectEqual('null', doc.title);
+
+    // Should have title element in head
+    const titleElement = doc.head.querySelector('title');
+    testing.expectEqual(true, titleElement !== null);
+    testing.expectEqual('null', titleElement.textContent);
+  }
+</script>
+
 <script id=createHTMLDocument_structure>
   {
     const impl = document.implementation;

src/browser/tests/element/css_style_properties.html

@@ -154,3 +154,11 @@
   testing.expectEqual(true, typeof div.style.getPropertyPriority === 'function');
 }
 </script>
+
+
+<div id=crash1 style="background-position: 5% .1em"></div>
+<script id="crash_case_1">
+{
+  testing.expectEqual('5% .1em', $('#crash1').style.backgroundPosition);
+}
+</script>

src/browser/tests/element/html/anchor.html

@@ -11,11 +11,11 @@
 <script id=empty_href>
   testing.expectEqual('', $('#a0').href);
 
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/anchor1.html', $('#a1').href);
-  testing.expectEqual('http://127.0.0.1:9582/hello/world/anchor2.html', $('#a2').href);
+  testing.expectEqual(testing.BASE_URL + 'element/anchor1.html', $('#a1').href);
+  testing.expectEqual(testing.ORIGIN + 'hello/world/anchor2.html', $('#a2').href);
   testing.expectEqual('https://www.openmymind.net/Elixirs-With-Statement/', $('#a3').href);
 
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/foo', $('#link').href);
+  testing.expectEqual(testing.BASE_URL + 'element/html/foo', $('#link').href);
 </script>
 
 <script id=dynamic_anchor_defaults>
@@ -129,7 +129,7 @@
   testing.expectEqual('https://foo.bar/?q=bar#frag', link.href);
 
   link.href = 'foo';
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/foo', link.href);
+  testing.expectEqual(testing.BASE_URL + 'element/html/foo', link.href);
 
   testing.expectEqual('', link.type);
   link.type = 'text/html';
@@ -245,3 +245,11 @@
   testing.expectEqual('', b.toString());
 }
 </script>
+
+<script id=url_encode>
+  {
+    let a = document.createElement('a');
+    a.href = 'over 9000!';
+    testing.expectEqual(testing.BASE_URL + 'element/html/over%209000!', a.href);
+  }
+</script>

src/browser/tests/element/html/details.html

@@ -0,0 +1,63 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<!-- Details elements -->
+<details id="details1">
+  <summary>Summary</summary>
+  Content
+</details>
+<details id="details2" open>
+  <summary>Open Summary</summary>
+  Content
+</details>
+
+<script id="instanceof">
+  {
+    const details = document.createElement('details')
+    testing.expectTrue(details instanceof HTMLDetailsElement)
+  }
+</script>
+
+<script id="open_initial">
+  testing.expectEqual(false, $('#details1').open)
+  testing.expectEqual(true, $('#details2').open)
+</script>
+
+<script id="open_set">
+  {
+    $('#details1').open = true
+    testing.expectEqual(true, $('#details1').open)
+
+    $('#details2').open = false
+    testing.expectEqual(false, $('#details2').open)
+  }
+</script>
+
+<script id="open_reflects_attribute">
+  {
+    const details = document.createElement('details')
+    testing.expectEqual(null, details.getAttribute('open'))
+
+    details.open = true
+    testing.expectEqual('', details.getAttribute('open'))
+
+    details.open = false
+    testing.expectEqual(null, details.getAttribute('open'))
+  }
+</script>
+
+<script id="name_initial">
+  {
+    const details = document.createElement('details')
+    testing.expectEqual('', details.name)
+  }
+</script>
+
+<script id="name_set">
+  {
+    const details = document.createElement('details')
+    details.name = 'group1'
+    testing.expectEqual('group1', details.name)
+    testing.expectEqual('group1', details.getAttribute('name'))
+  }
+</script>

src/browser/tests/element/html/event_listeners.html

@@ -143,6 +143,29 @@
 }
 </script>
 
+<script id="js_setter_null_clears_listener">
+{
+    // Setting an event handler property to null must silently clear it (not throw).
+    // Browsers also accept undefined and non-function values without throwing.
+    const div = document.createElement('div');
+
+    div.onload = () => 42;
+    testing.expectEqual('function', typeof div.onload);
+
+    // Setting to null removes the listener; getter returns null
+    div.onload = null;
+    testing.expectEqual(null, div.onload);
+
+    div.onerror = () => {};
+    div.onerror = null;
+    testing.expectEqual(null, div.onerror);
+
+    div.onclick = () => {};
+    div.onclick = null;
+    testing.expectEqual(null, div.onclick);
+}
+</script>
+
 <script id="different_event_types_independent">
 {
     // Test that different event types are stored independently

src/browser/tests/element/html/image.html

@@ -32,12 +32,12 @@
 
     img.src = 'test.png';
     // src property returns resolved absolute URL
-    testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/test.png', img.src);
+    testing.expectEqual(testing.BASE_URL + 'element/html/test.png', img.src);
     // getAttribute returns the raw attribute value
     testing.expectEqual('test.png', img.getAttribute('src'));
 
     img.src = '/absolute/path.png';
-    testing.expectEqual('http://127.0.0.1:9582/absolute/path.png', img.src);
+    testing.expectEqual(testing.ORIGIN + 'absolute/path.png', img.src);
     testing.expectEqual('/absolute/path.png', img.getAttribute('src'));
 
     img.src = 'https://example.com/image.png';
@@ -114,48 +114,15 @@
 }
 </script>
 
-<script id="load-trigger-event">
+<body></body>
+
+<script id="img-load-event">
 {
+  // An img fires a load event when src is set.
   const img = document.createElement("img");
-  let count = 0;
-  img.addEventListener("load", ({ bubbles, cancelBubble, cancelable, composed, isTrusted, target }) => {
-    testing.expectEqual(true, count < 3);
-    count++;
-
-    testing.expectEqual(false, bubbles);
-    testing.expectEqual(false, cancelBubble);
-    testing.expectEqual(false, cancelable);
-    testing.expectEqual(false, composed);
-    testing.expectEqual(true, isTrusted);
-    testing.expectEqual(img, target);
-  });
-
-  for (let i = 0; i < 3; i++) {
-    img.src = "https://cdn.lightpanda.io/website/assets/images/docs/hn.png";
-    testing.expectEqual("https://cdn.lightpanda.io/website/assets/images/docs/hn.png", img.src);
-  }
-
-  // Make sure count is incremented asynchronously.
-  testing.expectEqual(0, count);
-}
-</script>
-
-<img
-  id="inline-img"
-  src="https://cdn.lightpanda.io/website/assets/images/docs/hn.png"
-  onload="(() => testing.expectEqual(true, true))()"
-/>
-
-<script id="inline-on-load">
-{
-  const img = document.getElementById("inline-img");
-  testing.expectEqual(true, img.onload instanceof Function);
-  // Also call inline to double check.
-  img.onload();
-
-  // Make sure ones attached with `addEventListener` also executed.
+  let result = false;
   testing.async(async () => {
-    const result = await new Promise(resolve => {
+    await new Promise(resolve => {
       img.addEventListener("load", ({ bubbles, cancelBubble, cancelable, composed, isTrusted, target }) => {
         testing.expectEqual(false, bubbles);
         testing.expectEqual(false, cancelBubble);
@@ -163,12 +130,46 @@
         testing.expectEqual(false, composed);
         testing.expectEqual(true, isTrusted);
         testing.expectEqual(img, target);
-
-        return resolve(true);
+        result = true;
+        return resolve();
       });
+      img.src = "https://cdn.lightpanda.io/website/assets/images/docs/hn.png";
     });
-
-    testing.expectEqual(true, result);
   });
+
+  testing.eventually(() => testing.expectEqual(true, result));
 }
 </script>
+
+<script id="img-no-load-without-src">
+{
+  // An img without src should not fire a load event.
+  let fired = false;
+  const img = document.createElement("img");
+  img.addEventListener("load", () => { fired = true; });
+  document.body.appendChild(img);
+  testing.eventually(() => testing.expectEqual(false, fired));
+}
+</script>
+
+<script id="lazy-src-set">
+{
+  // Append to DOM first, then set src — load should still fire.
+  const img = document.createElement("img");
+  let result = false;
+  img.onload = () => result = true;
+  document.body.appendChild(img);
+  img.src = "https://cdn.lightpanda.io/website/assets/images/docs/hn.png";
+
+  testing.eventually(() => testing.expectEqual(true, result));
+}
+</script>
+
+<script id=url_encode>
+  {
+    let img = document.createElement('img');
+    img.src = 'over 9000!?hello=world !';
+    testing.expectEqual('over 9000!?hello=world !', img.getAttribute('src'));
+    testing.expectEqual(testing.BASE_URL + 'element/html/over%209000!?hello=world%20!', img.src);
+  }
+</script>

src/browser/tests/element/html/input.html

@@ -46,7 +46,7 @@
     testing.expectEqual(5, input.maxLength);
     input.maxLength = 'banana';
     testing.expectEqual(0, input.maxLength);
-    testing.expectError('Error: NegativeValueNotAllowed', () => { input.maxLength = -45;});
+    testing.expectError('IndexSizeError: Index or size is negative or greater than the allowed amount', () => { input.maxLength = -45;});
 
     testing.expectEqual(20, input.size);
     input.size = 5;
@@ -57,9 +57,9 @@
 
     testing.expectEqual('', input.src);
     input.src = 'foo'
-    testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/foo', input.src);
+    testing.expectEqual(testing.BASE_URL + 'element/html/foo', input.src);
     input.src = '-3'
-    testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/-3', input.src);
+    testing.expectEqual(testing.BASE_URL + 'element/html/-3', input.src);
     input.src = ''
   }
 </script>
@@ -221,6 +221,44 @@
   }
 </script>
 
+<script id="select_event">
+  {
+    const input = document.createElement('input');
+    input.value = 'Hello World';
+    document.body.appendChild(input);
+
+    let eventCount = 0;
+    let lastEvent = null;
+
+    input.addEventListener('select', (e) => {
+      eventCount++;
+      lastEvent = e;
+    });
+
+    let onselectFired = false;
+    input.onselect = () => { onselectFired = true; };
+
+    let bubbledToBody = false;
+    document.body.addEventListener('select', () => {
+      bubbledToBody = true;
+    });
+
+    testing.expectEqual(0, eventCount);
+
+    input.select();
+
+    testing.eventually(() => {
+      testing.expectEqual(1, eventCount);
+      testing.expectEqual('select', lastEvent.type);
+      testing.expectEqual(input, lastEvent.target);
+      testing.expectEqual(true, lastEvent.bubbles);
+      testing.expectEqual(false, lastEvent.cancelable);
+      testing.expectEqual(true, bubbledToBody);
+      testing.expectEqual(true, onselectFired);
+    });
+  }
+</script>
+
 <script id="defaultChecked">
   testing.expectEqual(true, $('#check1').defaultChecked)
   testing.expectEqual(false, $('#check2').defaultChecked)

src/browser/tests/element/html/label.html

@@ -16,3 +16,59 @@
     testing.expectEqual('', l2.htmlFor);
   }
 </script>
+
+<label id="l2" for="input1"><span>Name</span></label>
+<input id="input2" type="text">
+<input id="input-hidden" type="hidden">
+<select id="sel1"><option>a</option></select>
+<button id="btn1">Click</button>
+<label id="l3"><input id="input3"><span>desc</span></label>
+<label id="l4"><span>no control here</span></label>
+<label id="l5"><label id="l5-inner"><input id="input5"></label></label>
+
+<script id="control">
+  {
+    // for attribute pointing to a text input
+    const l2 = document.getElementById('l2');
+    testing.expectEqual('input1', l2.control.id);
+
+    // for attribute pointing to a non-existent id
+    const lMissing = document.createElement('label');
+    lMissing.htmlFor = 'does-not-exist';
+    testing.expectEqual(null, lMissing.control);
+
+    // for attribute pointing to a hidden input -> not labelable, returns null
+    const lHidden = document.createElement('label');
+    lHidden.htmlFor = 'input-hidden';
+    document.body.appendChild(lHidden);
+    testing.expectEqual(null, lHidden.control);
+
+    // for attribute pointing to a select
+    const lSel = document.createElement('label');
+    lSel.htmlFor = 'sel1';
+    document.body.appendChild(lSel);
+    testing.expectEqual('sel1', lSel.control.id);
+
+    // for attribute pointing to a button
+    const lBtn = document.createElement('label');
+    lBtn.htmlFor = 'btn1';
+    document.body.appendChild(lBtn);
+    testing.expectEqual('btn1', lBtn.control.id);
+
+    // no for attribute: first labelable descendant
+    const l3 = document.getElementById('l3');
+    testing.expectEqual('input3', l3.control.id);
+
+    // no for attribute: no labelable descendant -> null
+    const l4 = document.getElementById('l4');
+    testing.expectEqual(null, l4.control);
+
+    // no for attribute: nested labels, first labelable in tree order
+    const l5 = document.getElementById('l5');
+    testing.expectEqual('input5', l5.control.id);
+
+    // label with no for and not in document -> null
+    const lDetached = document.createElement('label');
+    testing.expectEqual(null, lDetached.control);
+  }
+</script>

src/browser/tests/element/html/link.html

@@ -8,7 +8,7 @@
   testing.expectEqual('https://lightpanda.io/opensource-browser/15', l2.href);
 
   l2.href = '/over/9000';
-  testing.expectEqual('http://127.0.0.1:9582/over/9000', l2.href);
+  testing.expectEqual(testing.ORIGIN + 'over/9000', l2.href);
 
   l2.crossOrigin = 'nope';
   testing.expectEqual('anonymous', l2.crossOrigin);
@@ -19,3 +19,68 @@
   l2.crossOrigin = '';
   testing.expectEqual('anonymous', l2.crossOrigin);
 </script>
+
+<script id="link-load-event">
+{
+  // A link with rel=stylesheet and a non-empty href fires a load event when appended to the DOM
+  const link = document.createElement('link');
+  link.rel = 'stylesheet';
+  link.href = 'https://lightpanda.io/opensource-browser/15';
+
+  testing.async(async () => {
+    const result = await new Promise(resolve => {
+      link.addEventListener('load', ({ bubbles, cancelBubble, cancelable, composed, isTrusted, target }) => {
+        testing.expectEqual(false, bubbles);
+        testing.expectEqual(false, cancelBubble);
+        testing.expectEqual(false, cancelable);
+        testing.expectEqual(false, composed);
+        testing.expectEqual(true, isTrusted);
+        testing.expectEqual(link, target);
+        resolve(true);
+      });
+      document.head.appendChild(link);
+    });
+    testing.expectEqual(true, result);
+  });
+  testing.expectEqual(true, true);
+}
+</script>
+
+<script id="link-no-load-without-href">
+{
+  // A link with rel=stylesheet but no href should not fire a load event
+  let fired = false;
+  const link = document.createElement('link');
+  link.rel = 'stylesheet';
+  link.addEventListener('load', () => { fired = true; });
+  document.head.appendChild(link);
+  testing.eventually(() => testing.expectEqual(false, fired));
+}
+</script>
+
+<script id="link-no-load-wrong-rel">
+{
+  // A link without rel=stylesheet should not fire a load event
+  let fired = false;
+  const link = document.createElement('link');
+  link.href = 'https://lightpanda.io/opensource-browser/15';
+  link.addEventListener('load', () => { fired = true; });
+  document.head.appendChild(link);
+  testing.eventually(() => testing.expectEqual(false, fired));
+}
+</script>
+
+<script id="lazy-href-set">
+{
+  let result = false;
+  const link = document.createElement("link");
+  link.rel = "stylesheet";
+  link.onload = () => result = true;
+  // Append to DOM,
+  document.head.appendChild(link);
+  // then set href.
+  link.href = 'https://lightpanda.io/opensource-browser/15';
+
+  testing.eventually(() => testing.expectEqual(true, result));
+}
+</script>

src/browser/tests/element/html/media.html

@@ -238,7 +238,7 @@
     testing.expectEqual('', audio.src);
 
     audio.src = 'test.mp3';
-    testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/test.mp3', audio.src);
+    testing.expectEqual(testing.BASE_URL + 'element/html/test.mp3', audio.src);
   }
 </script>
 
@@ -248,7 +248,7 @@
     testing.expectEqual('', video.poster);
 
     video.poster = 'poster.jpg';
-    testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/element/html/poster.jpg', video.poster);
+    testing.expectEqual(testing.BASE_URL + 'element/html/poster.jpg', video.poster);
   }
 </script>
 

src/browser/tests/element/html/option.html

@@ -29,6 +29,12 @@
   testing.expectEqual('Text 3', $('#opt3').text)
 </script>
 
+<script id="text_set">
+  $('#opt1').text = 'New Text 1'
+  testing.expectEqual('New Text 1', $('#opt1').text)
+  testing.expectEqual('New Text 1', $('#opt1').textContent)
+</script>
+
 <script id="selected">
   testing.expectEqual(false, $('#opt1').selected)
   testing.expectEqual(true, $('#opt2').selected)

src/browser/tests/element/html/script/script.html

@@ -2,11 +2,28 @@
 <script src="../../../testing.js"></script>
 
 <script id="script">
-   {
-    let s = document.createElement('script');
-    testing.expectEqual('', s.src);
+{
+   let dom_load = false;
+   let attribute_load = false;
 
-    s.src = '/over.9000.js';
-    testing.expectEqual('http://127.0.0.1:9582/over.9000.js', s.src);
+   let s = document.createElement('script');
+   document.documentElement.addEventListener('load', (e) => {
+      testing.expectEqual(s, e.target);
+      dom_load = true;
+   }, true);
+
+   testing.expectEqual('', s.src);
+   s.onload = function(e) {
+      testing.expectEqual(s, e.target);
+      attribute_load = true;
    }
+   s.src = 'empty.js';
+   testing.expectEqual(testing.BASE_URL + 'element/html/script/empty.js', s.src);
+   document.head.appendChild(s);
+
+   testing.eventually(() => {
+      testing.expectEqual(true, dom_load);
+      testing.expectEqual(true, attribute_load);
+   });
+}
 </script>

src/browser/tests/element/html/style.html

@@ -106,3 +106,28 @@
     testing.expectEqual(true, style.disabled);
   }
 </script>
+
+<script id="style-load-event">
+{
+  // A style element fires a load event when appended to the DOM.
+  const style = document.createElement("style");
+  let result = false;
+  testing.async(async () => {
+    await new Promise(resolve => {
+      style.addEventListener("load", ({ bubbles, cancelBubble, cancelable, composed, isTrusted, target }) => {
+        testing.expectEqual(false, bubbles);
+        testing.expectEqual(false, cancelBubble);
+        testing.expectEqual(false, cancelable);
+        testing.expectEqual(false, composed);
+        testing.expectEqual(true, isTrusted);
+        testing.expectEqual(style, target);
+        result = true;
+        return resolve();
+      });
+      document.head.appendChild(style);
+    });
+  });
+
+  testing.eventually(() => testing.expectEqual(true, result));
+}
+</script>

src/browser/tests/element/html/textarea.html

@@ -230,6 +230,44 @@
   }
 </script>
 
+<script id="select_event">
+  {
+    const textarea = document.createElement('textarea');
+    textarea.value = 'Hello World';
+    document.body.appendChild(textarea);
+
+    let eventCount = 0;
+    let lastEvent = null;
+
+    textarea.addEventListener('select', (e) => {
+      eventCount++;
+      lastEvent = e;
+    });
+
+    let onselectFired = false;
+    textarea.onselect = () => { onselectFired = true; };
+
+    let bubbledToBody = false;
+    document.body.addEventListener('select', () => {
+      bubbledToBody = true;
+    });
+
+    testing.expectEqual(0, eventCount);
+
+    textarea.select();
+
+    testing.eventually(() => {
+      testing.expectEqual(1, eventCount);
+      testing.expectEqual('select', lastEvent.type);
+      testing.expectEqual(textarea, lastEvent.target);
+      testing.expectEqual(true, lastEvent.bubbles);
+      testing.expectEqual(false, lastEvent.cancelable);
+      testing.expectEqual(true, bubbledToBody);
+      testing.expectEqual(true, onselectFired);
+    });
+  }
+</script>
+
 <script id="selectionchange_event">
   {
     const textarea = document.createElement('textarea');

src/browser/tests/element/html/track.html

@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<video id="video1">
+  <track id="track1" kind="subtitles">
+  <track id="track2" kind="captions">
+  <track id="track3" kind="invalid-kind">
+</video>
+
+<script id="instanceof">
+{
+  const track = document.createElement("track");
+  testing.expectEqual(true, track instanceof HTMLTrackElement);
+  testing.expectEqual("[object HTMLTrackElement]", track.toString());
+}
+</script>
+
+<script id="kind_default">
+{
+  const track = document.createElement("track");
+  testing.expectEqual("subtitles", track.kind);
+}
+</script>
+
+<script id="kind_valid_values">
+{
+  const track = document.createElement("track");
+
+  track.kind = "captions";
+  testing.expectEqual("captions", track.kind);
+
+  track.kind = "descriptions";
+  testing.expectEqual("descriptions", track.kind);
+
+  track.kind = "chapters";
+  testing.expectEqual("chapters", track.kind);
+
+  track.kind = "metadata";
+  testing.expectEqual("metadata", track.kind);
+}
+</script>
+
+<script id="kind_invalid">
+{
+  const track = document.createElement("track");
+
+  track.kind = null;
+  testing.expectEqual("metadata", track.kind);
+
+  track.kind = "Subtitles";
+  testing.expectEqual("subtitles", track.kind);
+
+  track.kind = "";
+  testing.expectEqual("metadata", track.kind);
+}
+</script>
+
+<script id="constants">
+{
+  const track = document.createElement("track");
+  testing.expectEqual(0, track.NONE);
+  testing.expectEqual(1, track.LOADING);
+  testing.expectEqual(2, track.LOADED);
+  testing.expectEqual(3, track.ERROR);
+}
+</script>
+
+<script id="constants_static">
+{
+  testing.expectEqual(0, HTMLTrackElement.NONE);
+  testing.expectEqual(1, HTMLTrackElement.LOADING);
+  testing.expectEqual(2, HTMLTrackElement.LOADED);
+  testing.expectEqual(3, HTMLTrackElement.ERROR);
+}
+</script>

src/browser/tests/element/inner.html

@@ -45,7 +45,6 @@
   testing.expectEqual('hi', $('#link').innerText);
 
   d1.innerHTML = '';
-  testing.todo(null, $('#link'));
 </script>
 
 <script id=attributeSerialization>

src/browser/tests/event/keyboard.html

@@ -103,3 +103,16 @@
   document.dispatchEvent(new KeyboardEvent('keytest', {key: 'b'}));
   testing.expectEqual(false, keyIsTrusted);
 </script>
+
+<script id=non_keyboard_keydown>
+  // this used to crash
+  {
+    let called = false;
+    const div = document.createElement('div')
+    div.addEventListener('keydown', () => {
+      called = true;
+    });
+    div.dispatchEvent(new Event('keydown'));
+    testing.expectEqual(true, called);
+  }
+</script>

src/browser/tests/file_reader.html

@@ -0,0 +1,197 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<script src="./testing.js"></script>
+
+<script id=basic>
+  {
+    const reader = new FileReader();
+    testing.expectEqual(0, reader.readyState);
+    testing.expectEqual(null, reader.result);
+    testing.expectEqual(null, reader.error);
+  }
+
+  // Constants
+  testing.expectEqual(0, FileReader.EMPTY);
+  testing.expectEqual(1, FileReader.LOADING);
+  testing.expectEqual(2, FileReader.DONE);
+</script>
+
+<script id=readAsText>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob(["Hello, World!"], { type: "text/plain" });
+
+    let loadstartFired = false;
+    let progressFired = false;
+    let loadFired = false;
+    let loadendFired = false;
+
+    const promise = new Promise((resolve) => {
+      reader.onloadstart = function(e) {
+        loadstartFired = true;
+        testing.expectEqual("loadstart", e.type);
+        testing.expectEqual(1, reader.readyState);
+      };
+
+      reader.onprogress = function(e) {
+        progressFired = true;
+        testing.expectEqual(13, e.loaded);
+        testing.expectEqual(13, e.total);
+      };
+
+      reader.onload = function(e) {
+        loadFired = true;
+        testing.expectEqual(2, reader.readyState);
+        testing.expectEqual("Hello, World!", reader.result);
+      };
+
+      reader.onloadend = function(e) {
+        loadendFired = true;
+        testing.expectEqual(true, loadstartFired);
+        testing.expectEqual(true, progressFired);
+        testing.expectEqual(true, loadFired);
+        resolve();
+      };
+    });
+
+    reader.readAsText(blob);
+    await promise;
+  });
+</script>
+
+<script id=readAsDataURL>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob(["test"], { type: "text/plain" });
+
+    const promise = new Promise((resolve) => {
+      reader.onload = function() {
+        testing.expectEqual("data:text/plain;base64,dGVzdA==", reader.result);
+        resolve();
+      };
+    });
+
+    reader.readAsDataURL(blob);
+    await promise;
+  });
+
+  // Empty MIME type
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob(["test"]);
+
+    const promise = new Promise((resolve) => {
+      reader.onload = function() {
+        testing.expectEqual("data:application/octet-stream;base64,dGVzdA==", reader.result);
+        resolve();
+      };
+    });
+
+    reader.readAsDataURL(blob);
+    await promise;
+  });
+</script>
+
+<script id=readAsArrayBuffer>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob([new Uint8Array([65, 66, 67])]);
+
+    const promise = new Promise((resolve) => {
+      reader.onload = function() {
+        const result = reader.result;
+        testing.expectEqual(true, result instanceof ArrayBuffer);
+        testing.expectEqual(3, result.byteLength);
+
+        const view = new Uint8Array(result);
+        testing.expectEqual(65, view[0]);
+        testing.expectEqual(66, view[1]);
+        testing.expectEqual(67, view[2]);
+        resolve();
+      };
+    });
+
+    reader.readAsArrayBuffer(blob);
+    await promise;
+  });
+</script>
+
+<script id=readAsBinaryString>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob(["ABC"]);
+
+    const promise = new Promise((resolve) => {
+      reader.onload = function() {
+        testing.expectEqual("ABC", reader.result);
+        resolve();
+      };
+    });
+
+    reader.readAsBinaryString(blob);
+    await promise;
+  });
+</script>
+
+<script id=abort>
+  // Test aborting when not loading (should do nothing)
+  {
+    const reader = new FileReader();
+    reader.abort(); // Should not throw
+    testing.expectEqual(0, reader.readyState);
+  }
+
+  // Note: Testing abort during read is implementation-dependent.
+  // In synchronous implementations (like ours), the read completes before abort can be called.
+  // In async implementations (like Firefox), you can abort during the read.
+  // We test that abort() at least doesn't throw and maintains correct state.
+</script>
+
+<script id=multipleReads>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob1 = new Blob(["first"]);
+    const blob2 = new Blob(["second"]);
+
+    // First read
+    const promise1 = new Promise((resolve) => {
+      reader.onload = function() {
+        testing.expectEqual("first", reader.result);
+        resolve();
+      };
+    });
+    reader.readAsText(blob1);
+    await promise1;
+
+    // Second read - should work after first completes
+    const promise2 = new Promise((resolve) => {
+      reader.onload = function() {
+        testing.expectEqual("second", reader.result);
+        resolve();
+      };
+    });
+    reader.readAsText(blob2);
+    await promise2;
+  });
+</script>
+
+<script id=addEventListener>
+  testing.async(async () => {
+    const reader = new FileReader();
+    const blob = new Blob(["test"]);
+
+    let loadFired = false;
+
+    const promise = new Promise((resolve) => {
+      reader.addEventListener("load", function() {
+        loadFired = true;
+        resolve();
+      });
+    });
+
+    reader.readAsText(blob);
+    await promise;
+
+    testing.expectEqual(true, loadFired);
+  });
+</script>

src/browser/tests/frames/frames.html

@@ -0,0 +1,94 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script>
+  function frame1Onload() {
+    window.f1_onload = 'f1_onload_loaded';
+  }
+</script>
+
+<iframe id=f1 onload="frame1Onload" src="support/sub 1.html"></iframe>
+<iframe id=f2 src="support/sub2.html"></iframe>
+
+<script id="basic">
+   // reload it
+  $('#f2').src = 'support/sub2.html';
+
+  testing.eventually(() => {
+    testing.expectEqual(undefined, window[10]);
+
+    testing.expectEqual(window, window[0].top);
+    testing.expectEqual(window, window[0].parent);
+    testing.expectEqual(false, window === window[0]);
+
+    testing.expectEqual(window, window[1].top);
+    testing.expectEqual(window, window[1].parent);
+    testing.expectEqual(false, window === window[1]);
+    testing.expectEqual(false, window[0] === window[1]);
+
+    testing.expectEqual(0, $('#f1').childNodes.length);
+
+    testing.expectEqual(testing.BASE_URL + 'frames/support/sub%201.html', $('#f1').src);
+    testing.expectEqual(window[0], $('#f1').contentWindow);
+    testing.expectEqual(window[1], $('#f2').contentWindow);
+
+    testing.expectEqual(window[0].document, $('#f1').contentDocument);
+    testing.expectEqual(window[1].document, $('#f2').contentDocument);
+
+    // sibling frames share the same top
+    testing.expectEqual(window[0].top, window[1].top);
+
+    // child frames have no sub-frames
+    testing.expectEqual(0, window[0].length);
+    testing.expectEqual(0, window[1].length);
+
+    // self and window are self-referential on child frames
+    testing.expectEqual(window[0], window[0].self);
+    testing.expectEqual(window[0], window[0].window);
+    testing.expectEqual(window[1], window[1].self);
+
+    // child frame's top.parent is itself (root has no parent)
+    testing.expectEqual(window, window[0].top.parent);
+
+    // Todo: Context security tokens
+    // testing.expectEqual(true, window.sub1_loaded);
+    // testing.expectEqual(true, window.sub2_loaded);
+    // testing.expectEqual(1, window.sub1_count);
+    // testing.expectEqual(2, window.sub2_count);
+  });
+</script>
+
+<script id=onload>
+  {
+    let f3_load_event = false;
+    let f3 = document.createElement('iframe');
+    f3.addEventListener('load', () => {
+      f3_load_event = true;
+    });
+    f3.src = 'invalid'; // still fires load!
+    document.documentElement.appendChild(f3);
+
+    testing.eventually(() => {
+      testing.expectEqual('f1_onload_loaded', window.f1_onload);
+      testing.expectEqual(true, f3_load_event);
+    });
+  }
+</script>
+
+<script id=onload>
+  {
+    let f4 = document.createElement('iframe');
+    f4.src = "about:blank";
+    document.documentElement.appendChild(f4);
+
+    testing.eventually(() => {
+      testing.expectEqual("<html><head></head><body></body></html>", f4.contentDocument.documentElement.outerHTML);
+    });
+  }
+</script>
+
+<script id=count>
+  testing.eventually(() => {
+    testing.expectEqual(4, window.length);
+  });
+</script>

src/browser/tests/frames/support/sub 1.html

@@ -0,0 +1,7 @@
+<!DOCTYPE html>
+<div id=div-1>sub1 div1</div>
+<script>
+  // should not have access to the parent's JS context
+  window.top.sub1_loaded = window.testing == undefined;
+  window.top.sub1_count = (window.top.sub1_count || 0) + 1;
+</script>

src/browser/tests/frames/support/sub2.html

@@ -0,0 +1,8 @@
+<!DOCTYPE html>
+<div id=div-1>sub2 div1</div>
+
+<script>
+  // should not have access to the parent's JS context
+  window.top.sub2_loaded = window.testing == undefined;
+  window.top.sub2_count = (window.top.sub2_count || 0) + 1;
+</script>

src/browser/tests/image_data.html

@@ -59,10 +59,6 @@
   }
 </script>
 
-<script id=constructor-invalid-colorspace>
-  testing.expectError("TypeError", () => {
-    new ImageData(5, 5, { colorSpace: "display-p3" });
-  });
 </script>
 
 <script id=single-pixel>
@@ -73,3 +69,7 @@
     testing.expectEqual(1, img.height);
   }
 </script>
+
+<script id=too-large>
+  testing.expectError("IndexSizeError", () => new ImageData(2_147_483_648, 2_147_483_648));
+</script>

src/browser/tests/legacy/html/input.html

@@ -43,7 +43,7 @@
   testing.expectEqual(5, input.maxLength);
   input.maxLength = 'banana';
   testing.expectEqual(0, input.maxLength);
-  testing.expectError('Error: NegativeValueNotAllowed', () => { input.maxLength = -45;});
+  testing.expectError('IndexSizeError: Index or size is negative or greater than the allowed amount', () => { input.maxLength = -45;});
 
   testing.expectEqual(20, input.size);
   input.size = 5;

src/browser/tests/legacy/html/script/script.html

@@ -19,3 +19,13 @@
 </script>
 
 <script id=datauri src="data:text/plain;charset=utf-8;base64,dGVzdGluZy5leHBlY3RFcXVhbCh0cnVlLCB0cnVlKTs="></script>
+
+<script id=datauri_url_encoded_text src="data:text/javascript,testing.expectEqual(3, 3);"></script>
+
+<script id=datauri_encoded_padding src="data:text/javascript;base64,dGVzdGluZy5leHBlY3RFcXVhbCgxLCAxKTs%3D"></script>
+
+<script id=datauri_fully_encoded src="data:text/javascript;base64,%64%47%56%7a%64%47%6c%75%5a%79%35%6c%65%48%42%6c%59%33%52%46%63%58%56%68%62%43%67%79%4c%43%41%79%4b%54%73%3d"></script>
+
+<script id=datauri_with_whitespace src="data:text/javascript;base64,%20ZD%20Qg%0D%0APS%20An%20Zm91cic%0D%0A%207%20"></script>
+
+<script id=datauri_url_encoded_unicode src="data:text/javascript,testing.expectEqual(4%2C%204)%3B"></script>

src/browser/tests/net/fetch.html

@@ -180,6 +180,13 @@
 
     testing.expectEqual(true, response.body !== null);
     testing.expectEqual(true, response.body instanceof ReadableStream);
+
+    const buf = await response.arrayBuffer()
+    restore();
+
+    const uint8array = new Uint8Array(buf);
+    const decoder = new TextDecoder('utf-8');
+    testing.expectEqual('1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890', decoder.decode(uint8array));
   });
 </script>
 

src/browser/tests/net/form_data.html

@@ -602,6 +602,114 @@
 }
 </script>
 
+<script id=disabledFieldset>
+{
+  // Elements inside a disabled fieldset should not be included
+  const form = document.createElement('form');
+
+  const fieldset = document.createElement('fieldset');
+  fieldset.disabled = true;
+
+  const inside = document.createElement('input');
+  inside.name = 'inside';
+  inside.value = 'nope';
+  fieldset.appendChild(inside);
+
+  const outside = document.createElement('input');
+  outside.name = 'outside';
+  outside.value = 'yes';
+
+  form.appendChild(fieldset);
+  form.appendChild(outside);
+
+  const fd = new FormData(form);
+  testing.expectEqual(null, fd.get('inside'));
+  testing.expectEqual('yes', fd.get('outside'));
+}
+</script>
+
+<script id=disabledFieldsetLegendExemption>
+{
+  // Elements inside the FIRST legend of a disabled fieldset are NOT disabled
+  const form = document.createElement('form');
+
+  const fieldset = document.createElement('fieldset');
+  fieldset.disabled = true;
+
+  const legend = document.createElement('legend');
+  const inLegend = document.createElement('input');
+  inLegend.name = 'in-legend';
+  inLegend.value = 'exempt';
+  legend.appendChild(inLegend);
+
+  const notInLegend = document.createElement('input');
+  notInLegend.name = 'not-in-legend';
+  notInLegend.value = 'nope';
+
+  fieldset.appendChild(legend);
+  fieldset.appendChild(notInLegend);
+  form.appendChild(fieldset);
+
+  const fd = new FormData(form);
+  testing.expectEqual('exempt', fd.get('in-legend'));
+  testing.expectEqual(null, fd.get('not-in-legend'));
+}
+</script>
+
+<script id=disabledFieldsetSecondLegend>
+{
+  // Only the FIRST legend gets the exemption; second legend inputs are still disabled
+  const form = document.createElement('form');
+
+  const fieldset = document.createElement('fieldset');
+  fieldset.disabled = true;
+
+  const legend1 = document.createElement('legend');
+  const inLegend1 = document.createElement('input');
+  inLegend1.name = 'first-legend';
+  inLegend1.value = 'exempt';
+  legend1.appendChild(inLegend1);
+
+  const legend2 = document.createElement('legend');
+  const inLegend2 = document.createElement('input');
+  inLegend2.name = 'second-legend';
+  inLegend2.value = 'nope';
+  legend2.appendChild(inLegend2);
+
+  fieldset.appendChild(legend1);
+  fieldset.appendChild(legend2);
+  form.appendChild(fieldset);
+
+  const fd = new FormData(form);
+  testing.expectEqual('exempt', fd.get('first-legend'));
+  testing.expectEqual(null, fd.get('second-legend'));
+}
+</script>
+
+<script id=disabledFieldsetNested>
+{
+  // Outer fieldset disabled: inner enabled fieldset's elements are still disabled
+  const form = document.createElement('form');
+
+  const outer = document.createElement('fieldset');
+  outer.disabled = true;
+
+  const inner = document.createElement('fieldset');
+  // inner is NOT disabled itself
+
+  const input = document.createElement('input');
+  input.name = 'deep';
+  input.value = 'nope';
+  inner.appendChild(input);
+
+  outer.appendChild(inner);
+  form.appendChild(outer);
+
+  const fd = new FormData(form);
+  testing.expectEqual(null, fd.get('deep'));
+}
+</script>
+
 <script id=imageWithoutName>
 {
   // Test that image input without name still submits x and y coordinates

src/browser/tests/net/request.html

@@ -111,7 +111,7 @@
 <script id=legacy>
   {
     let request = new Request("flower.png");
-    testing.expectEqual("http://127.0.0.1:9582/src/browser/tests/net/flower.png", request.url);
+    testing.expectEqual(testing.BASE_URL + 'net/flower.png', request.url);
     testing.expectEqual("GET", request.method);
 
     let request2 = new Request("https://google.com", {

src/browser/tests/net/xhr.html

@@ -252,3 +252,34 @@
     testing.expectEqual(XMLHttpRequest.UNSENT, req.readyState);
   });
 </script>
+
+
+<script id=xhr_abort_callback_nobody>
+  testing.async(async (restore) => {
+    const req = new XMLHttpRequest();
+    let abortFired = false;
+    let errorFired = false;
+    let loadEndFired = false;
+
+    await new Promise((resolve) => {
+      req.onabort = () => { abortFired = true; };
+      req.onerror = () => { errorFired = true; };
+      req.onloadend = () => {
+        loadEndFired = true;
+        resolve();
+      };
+
+      req.open('GET', 'http://127.0.0.1:9582/xhr_empty');
+      req.onreadystatechange = (e) => {
+        req.abort();
+      }
+      req.send();
+    });
+
+    restore();
+    testing.expectEqual(true, abortFired);
+    testing.expectEqual(true, errorFired);
+    testing.expectEqual(true, loadEndFired);
+    testing.expectEqual(XMLHttpRequest.UNSENT, req.readyState);
+  });
+</script>

src/browser/tests/node/base_uri.html

@@ -5,7 +5,7 @@
 <a href="foo" id="foo">foo</a>
 
 <script id=baseURI>
-  testing.expectEqual("http://127.0.0.1:9582/src/browser/tests/node/base_uri.html", document.URL);
+  testing.expectEqual(testing.BASE_URL + 'node/base_uri.html', document.URL);
   testing.expectEqual("https://example.com/", document.baseURI);
 
   const link = $('#foo');

src/browser/tests/node/noscript_serialization.html

@@ -0,0 +1,24 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<!-- When scripting is enabled the HTML parser treats <noscript> as a raw text
+     element: its entire content is stored as a single text node containing the
+     raw markup.  Serializing it back (outerHTML / innerHTML) must output that
+     markup as-is without HTML-escaping the angle brackets. -->
+<noscript id="ns1"><h1>Hello</h1><p>World</p></noscript>
+<noscript id="ns2"><div id="bsky_post_summary"><h3>Post</h3><p id="bsky_display_name">Henri Helvetica</p></div></noscript>
+
+<script id="noscript-outerHTML">
+  const ns1 = document.getElementById('ns1');
+  testing.expectEqual('<noscript id="ns1"><h1>Hello</h1><p>World</p></noscript>', ns1.outerHTML);
+</script>
+
+<script id="noscript-innerHTML">
+  const ns2 = document.getElementById('ns2');
+  testing.expectEqual('<div id="bsky_post_summary"><h3>Post</h3><p id="bsky_display_name">Henri Helvetica</p></div>', ns2.innerHTML);
+</script>
+
+<script id="noscript-textContent">
+  // The raw text node content must be the literal HTML markup (not parsed DOM)
+  testing.expectEqual('<h1>Hello</h1><p>World</p>', ns1.firstChild.nodeValue);
+</script>

src/browser/tests/performance.html

@@ -252,6 +252,72 @@
   }
 </script>
 
+<script id=measure_with_navigation_timing_marks>
+  {
+    // performance.measure() must accept PerformanceTiming attribute names
+    // (e.g. "fetchStart") as start/end marks per the W3C User Timing Level 2 spec.
+    // https://www.w3.org/TR/user-timing/#dom-performance-measure
+    performance.clearMarks();
+    performance.clearMeasures();
+
+    performance.mark("mark-dataComplete");
+    let m = performance.measure("dataComplete", "fetchStart", "mark-dataComplete");
+    testing.expectEqual('dataComplete', m.name);
+    testing.expectEqual('measure', m.entryType);
+    testing.expectEqual(true, m.duration >= 0);
+
+    // navigationStart is also a valid mark name (was already supported)
+    performance.mark("mark-end");
+    let m2 = performance.measure("fromNav", "navigationStart", "mark-end");
+    testing.expectEqual('fromNav', m2.name);
+    testing.expectEqual(true, m2.duration >= 0);
+  }
+</script>
+
+<script id=performance_timing_exists>
+  {
+    // performance.timing must not be undefined (used by sites like Bing)
+    testing.expectEqual(true, performance.timing !== undefined);
+    testing.expectEqual(true, performance.timing !== null);
+  }
+</script>
+
+<script id=performance_timing_navigationStart>
+  {
+    // navigationStart must be a number (sites access performance.timing.navigationStart)
+    const timing = performance.timing;
+    testing.expectEqual('number', typeof timing.navigationStart);
+    testing.expectEqual(0, timing.navigationStart);
+  }
+</script>
+
+<script id=performance_timing_all_properties>
+  {
+    // All PerformanceTiming properties must be accessible and return numbers
+    const timing = performance.timing;
+    const props = [
+      'navigationStart', 'unloadEventStart', 'unloadEventEnd',
+      'redirectStart', 'redirectEnd', 'fetchStart',
+      'domainLookupStart', 'domainLookupEnd',
+      'connectStart', 'connectEnd', 'secureConnectionStart',
+      'requestStart', 'responseStart', 'responseEnd',
+      'domLoading', 'domInteractive',
+      'domContentLoadedEventStart', 'domContentLoadedEventEnd',
+      'domComplete', 'loadEventStart', 'loadEventEnd',
+    ];
+    for (const prop of props) {
+      testing.expectEqual('number', typeof timing[prop]);
+    }
+  }
+</script>
+
+<script id=performance_timing_same_object>
+  {
+    // performance.timing should return the same object on each access
+    testing.expectEqual(true, performance.timing === performance.timing);
+  }
+</script>
+
 <script id=mixed_marks_and_measures>
   {
     performance.clearMarks();
@@ -280,3 +346,50 @@
     testing.expectEqual(0, remainingMarks.length);
   }
 </script>
+
+<script id=performance_timing_exists>
+  {
+    // Navigation Timing Level 1: performance.timing must be an object, not undefined
+    testing.expectEqual('object', typeof performance.timing);
+    testing.expectEqual(false, performance.timing === null);
+  }
+</script>
+
+<script id=performance_timing_navigationStart>
+  {
+    // The most commonly used property — must be a number (not undefined)
+    testing.expectEqual('number', typeof performance.timing.navigationStart);
+    testing.expectEqual(0, performance.timing.navigationStart);
+  }
+</script>
+
+<script id=performance_navigation_exists>
+  {
+    // Navigation Timing Level 1: performance.navigation must be an object, not undefined
+    testing.expectEqual('object', typeof performance.navigation);
+    testing.expectEqual(false, performance.navigation === null);
+    testing.expectEqual('number', typeof performance.navigation.type);
+    testing.expectEqual('number', typeof performance.navigation.redirectCount);
+    testing.expectEqual(0, performance.navigation.type);
+    testing.expectEqual(0, performance.navigation.redirectCount);
+  }
+</script>
+
+<script id=performance_timing_all_properties>
+  {
+    const t = performance.timing;
+    const props = [
+      'navigationStart', 'unloadEventStart', 'unloadEventEnd',
+      'redirectStart', 'redirectEnd', 'fetchStart',
+      'domainLookupStart', 'domainLookupEnd',
+      'connectStart', 'connectEnd', 'secureConnectionStart',
+      'requestStart', 'responseStart', 'responseEnd',
+      'domLoading', 'domInteractive',
+      'domContentLoadedEventStart', 'domContentLoadedEventEnd',
+      'domComplete', 'loadEventStart', 'loadEventEnd',
+    ];
+    for (const prop of props) {
+      testing.expectEqual('number', typeof t[prop]);
+    }
+  }
+</script>

src/browser/tests/selection.html

@@ -546,14 +546,14 @@
   {
     const sel = window.getSelection();
     sel.removeAllRanges();
-
     let eventCount = 0;
     let lastEvent = null;
 
-    document.addEventListener('selectionchange', (e) => {
+    const listener = (e) => {
       eventCount++;
       lastEvent = e;
-    });
+    };
+    document.addEventListener('selectionchange', listener);
 
     const p1 = document.getElementById("p1");
     const textNode = p1.firstChild;
@@ -563,27 +563,25 @@
     sel.extend(textNode, 10);
     sel.collapseToStart();
     sel.collapseToEnd();
-
     sel.removeAllRanges();
     const range = document.createRange();
     range.setStart(textNode, 4);
     range.setEnd(textNode, 15);
     sel.addRange(range);
-
     sel.removeRange(range);
-
     const newRange = document.createRange();
     newRange.selectNodeContents(p1);
     sel.addRange(newRange);
     sel.removeAllRanges();
-
     sel.selectAllChildren(nested);
     sel.setBaseAndExtent(textNode, 4, textNode, 15);
-
     sel.collapse(textNode, 5);
     sel.extend(textNode, 10);
     sel.deleteFromDocument();
 
+    document.removeEventListener('selectionchange', listener);
+    textNode.textContent = "The quick brown fox";
+
     testing.eventually(() => {
       testing.expectEqual(14, eventCount);
       testing.expectEqual('selectionchange', lastEvent.type);
@@ -593,3 +591,149 @@
     });
   }
 </script>
+
+<script id=modifyCharacterForward>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    const textNode = p1.firstChild; // "The quick brown fox"
+
+    // Collapse to position 4 (after "The ")
+    sel.collapse(textNode, 4);
+    testing.expectEqual(4, sel.anchorOffset);
+
+    // Move forward one character
+    sel.modify("move", "forward", "character");
+    testing.expectEqual(5, sel.anchorOffset);
+    testing.expectEqual(true, sel.isCollapsed);
+    testing.expectEqual("none", sel.direction);
+
+    // Move forward again
+    sel.modify("move", "forward", "character");
+    testing.expectEqual(6, sel.anchorOffset);
+  }
+</script>
+
+<script id=modifyWordForward>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    const textNode = p1.firstChild; // "The quick brown fox"
+
+    // Collapse to start
+    sel.collapse(textNode, 0);
+
+    // Move forward one word - should land at end of "The"
+    sel.modify("move", "forward", "word");
+    testing.expectEqual(3, sel.anchorOffset);
+    testing.expectEqual(true, sel.isCollapsed);
+
+    // Move forward again - should skip space and land at end of "quick"
+    sel.modify("move", "forward", "word");
+    testing.expectEqual(9, sel.anchorOffset);
+  }
+</script>
+
+<script id=modifyCharacterBackward>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    const textNode = p1.firstChild; // "The quick brown fox"
+
+    // Collapse to position 6
+    sel.collapse(textNode, 6);
+    testing.expectEqual(6, sel.anchorOffset);
+
+    // Move backward one character
+    sel.modify("move", "backward", "character");
+    testing.expectEqual(5, sel.anchorOffset);
+    testing.expectEqual(true, sel.isCollapsed);
+    testing.expectEqual("none", sel.direction);
+
+    // Move backward again
+    sel.modify("move", "backward", "character");
+    testing.expectEqual(4, sel.anchorOffset);
+  }
+</script>
+
+<script id=modifyWordBackward>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    const textNode = p1.firstChild; // "The quick brown fox"
+
+    // Collapse to end of "quick" (offset 9)
+    sel.collapse(textNode, 9);
+
+    // Move backward one word - should land at start of "quick"
+    sel.modify("move", "backward", "word");
+    testing.expectEqual(4, sel.anchorOffset);
+    testing.expectEqual(true, sel.isCollapsed);
+
+    // Move backward again - should land at start of "The"
+    sel.modify("move", "backward", "word");
+    testing.expectEqual(0, sel.anchorOffset);
+  }
+</script>
+
+<script id=modifyCharacterForwardFromElementNode>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    sel.collapse(p1, 1);
+
+    testing.expectEqual(p1, sel.anchorNode);
+    testing.expectEqual(1, sel.anchorOffset);
+    testing.expectEqual(true, sel.isCollapsed);
+
+    sel.modify("move", "forward", "character");
+
+    testing.expectEqual(3, sel.anchorNode.nodeType);
+    testing.expectEqual(true, sel.anchorNode !== p1.firstChild);
+  }
+</script>
+
+<script id=modifyCharacterForwardFromElementNodeMidChildren>
+  {
+    const sel = window.getSelection();
+    const nested = document.getElementById("nested");
+
+    sel.collapse(nested, nested.childNodes.length);
+
+    testing.expectEqual(nested, sel.anchorNode);
+    testing.expectEqual(nested.childNodes.length, sel.anchorOffset);
+
+    sel.modify("move", "forward", "character");
+
+    // Must land on a text node strictly after #nested
+    testing.expectEqual(3, sel.anchorNode.nodeType);
+    testing.expectEqual(false, nested.contains(sel.anchorNode));
+  }
+</script>
+
+<script id=modifyWordForwardFromElementNode>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+    sel.collapse(p1, 1);
+
+    sel.modify("move", "forward", "word");
+
+    // Must land on a text node strictly after p1
+    testing.expectEqual(3, sel.anchorNode.nodeType);
+    testing.expectEqual(false, p1.contains(sel.anchorNode));
+    testing.expectEqual(true, sel.isCollapsed);
+  }
+</script>
+
+<script id=modifyCharacterForwardNewNodeOffsetNotElement>
+  {
+    const sel = window.getSelection();
+    const p1 = document.getElementById("p1");
+
+    sel.collapse(p1, 1);
+    sel.modify("move", "forward", "character");
+
+    testing.expectEqual(3, sel.anchorNode.nodeType);
+  }
+</script>

src/browser/tests/storage.html

@@ -88,3 +88,12 @@
   localStorage.clear();
   testing.expectEqual(0, localStorage.length)
 </script>
+
+<script id="localstorage_limits">
+  localStorage.clear();
+  for (i = 0; i < 5; i++) {
+    const v =  "v".repeat(1024 * 1024);
+    localStorage.setItem(v, v);
+  }
+  testing.expectError("QuotaExceededError", () => localStorage.setItem("last", "v"));
+</script>

src/browser/tests/streams/readable_stream.html

@@ -301,3 +301,74 @@
     testing.expectEqual(false, data3.done);
   })();
 </script>
+
+<script id=enqueue_preserves_number>
+  (async function() {
+    const stream = new ReadableStream({
+      start(controller) {
+        controller.enqueue(42);
+        controller.enqueue(0);
+        controller.enqueue(3.14);
+        controller.close();
+      }
+    });
+
+    const reader = stream.getReader();
+
+    const r1 = await reader.read();
+    testing.expectEqual(false, r1.done);
+    testing.expectEqual('number', typeof r1.value);
+    testing.expectEqual(42, r1.value);
+
+    const r2 = await reader.read();
+    testing.expectEqual('number', typeof r2.value);
+    testing.expectEqual(0, r2.value);
+
+    const r3 = await reader.read();
+    testing.expectEqual('number', typeof r3.value);
+    testing.expectEqual(3.14, r3.value);
+
+    const r4 = await reader.read();
+    testing.expectEqual(true, r4.done);
+  })();
+</script>
+
+<script id=enqueue_preserves_bool>
+  (async function() {
+    const stream = new ReadableStream({
+      start(controller) {
+        controller.enqueue(true);
+        controller.enqueue(false);
+        controller.close();
+      }
+    });
+
+    const reader = stream.getReader();
+
+    const r1 = await reader.read();
+    testing.expectEqual('boolean', typeof r1.value);
+    testing.expectEqual(true, r1.value);
+
+    const r2 = await reader.read();
+    testing.expectEqual('boolean', typeof r2.value);
+    testing.expectEqual(false, r2.value);
+  })();
+</script>
+
+<script id=enqueue_preserves_object>
+  (async function() {
+    const stream = new ReadableStream({
+      start(controller) {
+        controller.enqueue({ key: 'value', num: 7 });
+        controller.close();
+      }
+    });
+
+    const reader = stream.getReader();
+
+    const r1 = await reader.read();
+    testing.expectEqual('object', typeof r1.value);
+    testing.expectEqual('value', r1.value.key);
+    testing.expectEqual(7, r1.value.num);
+  })();
+</script>

src/browser/tests/streams/text_decoder_stream.html

@@ -0,0 +1,82 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id=text_decoder_stream_encoding>
+  {
+    const tds = new TextDecoderStream();
+    testing.expectEqual('utf-8', tds.encoding);
+    testing.expectEqual('object', typeof tds.readable);
+    testing.expectEqual('object', typeof tds.writable);
+    testing.expectEqual(false, tds.fatal);
+    testing.expectEqual(false, tds.ignoreBOM);
+  }
+</script>
+
+<script id=text_decoder_stream_with_label>
+  {
+    const tds = new TextDecoderStream('utf-8');
+    testing.expectEqual('utf-8', tds.encoding);
+  }
+</script>
+
+<script id=text_decoder_stream_with_opts>
+  {
+    const tds = new TextDecoderStream('utf-8', { fatal: true, ignoreBOM: true });
+    testing.expectEqual(true, tds.fatal);
+    testing.expectEqual(true, tds.ignoreBOM);
+  }
+</script>
+
+<script id=text_decoder_stream_invalid_label>
+  {
+    let errorThrown = false;
+    try {
+      new TextDecoderStream('windows-1252');
+    } catch (e) {
+      errorThrown = true;
+    }
+    testing.expectEqual(true, errorThrown);
+  }
+</script>
+
+<script id=text_decoder_stream_decode>
+  (async function() {
+    const tds = new TextDecoderStream();
+
+    const writer = tds.writable.getWriter();
+    const reader = tds.readable.getReader();
+
+    // 'hello' in UTF-8 bytes
+    const bytes = new Uint8Array([104, 101, 108, 108, 111]);
+    await writer.write(bytes);
+    await writer.close();
+
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual('hello', result.value);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>
+
+<script id=text_decoder_stream_empty_chunk>
+  (async function() {
+    const tds = new TextDecoderStream();
+    const writer = tds.writable.getWriter();
+    const reader = tds.readable.getReader();
+
+    // Write an empty chunk followed by real data
+    await writer.write(new Uint8Array([]));
+    await writer.write(new Uint8Array([104, 105]));
+    await writer.close();
+
+    // Empty chunk should be filtered out; first read gets "hi"
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual('hi', result.value);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>

src/browser/tests/streams/transform_stream.html

@@ -0,0 +1,164 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id=transform_stream_basic>
+  {
+    const ts = new TransformStream();
+    testing.expectEqual('object', typeof ts);
+    testing.expectEqual('object', typeof ts.readable);
+    testing.expectEqual('object', typeof ts.writable);
+  }
+</script>
+
+<script id=transform_stream_with_transformer>
+  (async function() {
+    const ts = new TransformStream({
+      transform(chunk, controller) {
+        controller.enqueue(chunk.toUpperCase());
+      }
+    });
+
+    const writer = ts.writable.getWriter();
+    const reader = ts.readable.getReader();
+
+    await writer.write('hello');
+    await writer.close();
+
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual('HELLO', result.value);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>
+
+<script id=writable_stream_basic>
+  {
+    const ws = new WritableStream();
+    testing.expectEqual('object', typeof ws);
+    testing.expectEqual(false, ws.locked);
+  }
+</script>
+
+<script id=writable_stream_writer>
+  {
+    const ws = new WritableStream();
+    const writer = ws.getWriter();
+    testing.expectEqual('object', typeof writer);
+    testing.expectEqual(true, ws.locked);
+  }
+</script>
+
+<script id=writable_stream_writer_desired_size>
+  {
+    const ws = new WritableStream();
+    const writer = ws.getWriter();
+    testing.expectEqual(1, writer.desiredSize);
+  }
+</script>
+
+<script id=text_encoder_stream_encoding>
+  {
+    const tes = new TextEncoderStream();
+    testing.expectEqual('utf-8', tes.encoding);
+    testing.expectEqual('object', typeof tes.readable);
+    testing.expectEqual('object', typeof tes.writable);
+  }
+</script>
+
+<script id=text_encoder_stream_encode>
+  (async function() {
+    const tes = new TextEncoderStream();
+
+    const writer = tes.writable.getWriter();
+    const reader = tes.readable.getReader();
+
+    await writer.write('hi');
+    await writer.close();
+
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual(true, result.value instanceof Uint8Array);
+    // 'hi' in UTF-8 is [104, 105]
+    testing.expectEqual(104, result.value[0]);
+    testing.expectEqual(105, result.value[1]);
+    testing.expectEqual(2, result.value.length);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>
+
+<script id=pipe_through_basic>
+  (async function() {
+    const input = new ReadableStream({
+      start(controller) {
+        controller.enqueue('hello');
+        controller.close();
+      }
+    });
+
+    const ts = new TransformStream({
+      transform(chunk, controller) {
+        controller.enqueue(chunk.toUpperCase());
+      }
+    });
+
+    const output = input.pipeThrough(ts);
+    const reader = output.getReader();
+
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual('HELLO', result.value);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>
+
+<script id=pipe_to_basic>
+  (async function() {
+    const chunks = [];
+    const input = new ReadableStream({
+      start(controller) {
+        controller.enqueue('a');
+        controller.enqueue('b');
+        controller.close();
+      }
+    });
+
+    const ws = new WritableStream({
+      write(chunk) {
+        chunks.push(chunk);
+      }
+    });
+
+    await input.pipeTo(ws);
+    testing.expectEqual(2, chunks.length);
+    testing.expectEqual('a', chunks[0]);
+    testing.expectEqual('b', chunks[1]);
+  })();
+</script>
+
+<script id=pipe_through_text_decoder>
+  (async function() {
+    const bytes = new Uint8Array([104, 101, 108, 108, 111]);
+    const input = new ReadableStream({
+      start(controller) {
+        controller.enqueue(bytes);
+        controller.close();
+      }
+    });
+
+    const output = input.pipeThrough(new TextDecoderStream());
+    const reader = output.getReader();
+
+    const result = await reader.read();
+    testing.expectEqual(false, result.done);
+    testing.expectEqual('hello', result.value);
+
+    const result2 = await reader.read();
+    testing.expectEqual(true, result2.done);
+  })();
+</script>

src/browser/tests/testing.js

@@ -99,6 +99,9 @@
     }
   }
 
+  // our test runner sets this to true
+  const IS_TEST_RUNNER = window._lightpanda_skip_auto_assert === true;
+
   window.testing = {
     fail: fail,
     async: async,
@@ -109,9 +112,24 @@
     expectError: expectError,
     withError: withError,
     eventually: eventually,
-    todo: function(){},
+    IS_TEST_RUNNER: IS_TEST_RUNNER,
+    HOST: '127.0.0.1',
+    ORIGIN: 'http://127.0.0.1:9582/',
+    BASE_URL: 'http://127.0.0.1:9582/src/browser/tests/',
   };
 
+  if (!IS_TEST_RUNNER) {
+    // The page is running in a different browser. Probably a developer making sure
+    // a test is correct. There are a few tweaks we need to do to make this a
+    // seemless, namely around adapting paths/urls.
+    console.warn(`The page is not being executed in the test runner, certain behavior has been adjusted`);
+    window.testing.HOST = location.hostname;
+    window.testing.ORIGIN = location.origin + '/';
+    window.testing.BASE_URL = location.origin + '/src/browser/tests/';
+    window.addEventListener('load', testing.assertOk);
+  }
+
+
   window.$ = function(sel) {
     return document.querySelector(sel);
   }

src/browser/tests/url.html

@@ -656,3 +656,45 @@
     testing.expectEqual("?a=%7E&b=%7E&c=foo", url.search);
   }
 </script>
+
+<script id=objectURL>
+{
+  // Test createObjectURL with Blob
+  const blob = new Blob(['<html><body>Hello</body></html>'], { type: 'text/html' });
+  const url = URL.createObjectURL(blob);
+
+  testing.expectEqual('string', typeof url);
+  testing.expectEqual(true, url.startsWith('blob:'));
+  testing.expectEqual(true, url.includes('http'));
+}
+
+{
+  // Test revokeObjectURL
+  const blob = new Blob(['test'], { type: 'text/plain' });
+  const url = URL.createObjectURL(blob);
+
+  testing.expectEqual(true, url.startsWith('blob:'));
+
+  URL.revokeObjectURL(url);
+  URL.revokeObjectURL(url); // Second revoke should be safe
+}
+
+{
+  // Test with non-blob URL (should be safe/silent)
+  URL.revokeObjectURL('http://example.com/notblob');
+  URL.revokeObjectURL('');
+  testing.expectEqual(true, true);
+}
+
+{
+  // Test uniqueness
+  const blob1 = new Blob(['test1']);
+  const blob2 = new Blob(['test2']);
+  const url1 = URL.createObjectURL(blob1);
+  const url2 = URL.createObjectURL(blob2);
+
+  testing.expectEqual(false, url1 === url2);
+  testing.expectEqual(true, url1.startsWith('blob:'));
+  testing.expectEqual(true, url2.startsWith('blob:'));
+}
+</script>

src/browser/tests/window/location.html

@@ -2,24 +2,24 @@
 <script src="../testing.js"></script>
 
 <script id=location>
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/window/location.html', window.location.href);
+  testing.expectEqual(testing.BASE_URL + 'window/location.html', window.location.href);
   testing.expectEqual(document.location, window.location);
 </script>
 
 <script id=location_hash>
   location.hash = "";
   testing.expectEqual("", location.hash);
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/window/location.html', location.href);
+  testing.expectEqual(testing.BASE_URL + 'window/location.html', location.href);
 
   location.hash = "#abcdef";
   testing.expectEqual("#abcdef", location.hash);
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/window/location.html#abcdef', location.href);
+  testing.expectEqual(testing.BASE_URL + 'window/location.html#abcdef', location.href);
 
   location.hash = "xyzxyz";
   testing.expectEqual("#xyzxyz", location.hash);
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/window/location.html#xyzxyz', location.href);
+  testing.expectEqual(testing.BASE_URL + 'window/location.html#xyzxyz', location.href);
 
   location.hash = "";
   testing.expectEqual("", location.hash);
-  testing.expectEqual('http://127.0.0.1:9582/src/browser/tests/window/location.html', location.href);
+  testing.expectEqual(testing.BASE_URL + 'window/location.html', location.href);
 </script>

src/browser/tests/window/screen.html

@@ -3,8 +3,10 @@
 
 <script id=screen>
   let screen = window.screen;
-  testing.expectEqual(1920, screen.width);
-  testing.expectEqual(1080, screen.height);
+  if (testing.IS_TEST_RUNNER) {
+    testing.expectEqual(1920, screen.width);
+    testing.expectEqual(1080, screen.height);
+  }
 
   let orientation = screen.orientation;
   testing.expectEqual(0, orientation.angle);

src/browser/tests/window/scroll.html

@@ -37,6 +37,12 @@
 
     restore();
     testing.expectEqual(2, scrollevt);
-    testing.expectEqual(1, scrollendevt);
+    // This test used to assert that scrollendevt == 1. The idea being that
+    // the above resolve() would stop the test running after "scroll" fires but
+    // before "scrollend" fires. That timing is pretty sensitive/fragile. If
+    // the browser gets delayed and doesn't figure the scroll event exactly when
+    // schedule, it could easily execute in the same sheduler.run call as the
+    // scrollend.
+    testing.expectEqual(true, scrollendevt === 1 || scrollendevt === 2);
   });
 </script>

src/browser/tests/window/timers.html

@@ -23,7 +23,6 @@
   });
 </script>
 
-
 <script id=setTimeout>
   testing.expectEqual(1, window.setTimeout.length);
   let wst2 = 1;
@@ -32,3 +31,11 @@
   }, 1, 2, 3);
   testing.eventually(() => testing.expectEqual(5, wst2));
 </script>
+
+<script id=invalid-timer-clear>
+  // Surprisingly, these don't fail but silently ignored.
+  clearTimeout(-1);
+  clearInterval(-2);
+  clearImmediate(-3);
+  testing.expectEqual(true, true);
+</script>

src/browser/tests/window/window.html

@@ -75,6 +75,16 @@
   testing.expectEqual('abc', atob('YWJj'));
   testing.expectEqual('0123456789', atob('MDEyMzQ1Njc4OQ=='));
   testing.expectEqual('The quick brown fox jumps over the lazy dog', atob('VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw=='));
+
+  // atob must accept unpadded base64 (forgiving-base64 decode per HTML spec)
+  testing.expectEqual('a', atob('YQ'));      // 2 chars, len%4==2, needs '=='
+  testing.expectEqual('ab', atob('YWI'));    // 3 chars, len%4==3, needs '='
+  testing.expectEqual('ceil', atob('Y2VpbA'));  // 6 chars, len%4==2, needs '=='
+
+  // length % 4 == 1 must still throw
+  testing.expectError('Error: InvalidCharacterError', () => {
+    atob('Y');
+  });
 </script>
 
 <script id=btoa_atob_roundtrip>

src/browser/tests/window_scroll.html

@@ -0,0 +1,36 @@
+<!DOCTYPE html>
+<script src="testing.js"></script>
+
+<script id=scrollBy_exists>
+  testing.expectEqual('function', typeof window.scrollBy);
+</script>
+
+<script id=scrollBy_xy>
+  window.scrollTo(0, 0);
+  testing.expectEqual(0, window.scrollX);
+  testing.expectEqual(0, window.scrollY);
+  window.scrollBy(100, 200);
+  testing.expectEqual(100, window.scrollX);
+  testing.expectEqual(200, window.scrollY);
+</script>
+
+<script id=scrollBy_relative>
+  window.scrollTo(100, 100);
+  window.scrollBy(50, 50);
+  testing.expectEqual(150, window.scrollX);
+  testing.expectEqual(150, window.scrollY);
+</script>
+
+<script id=scrollBy_opts>
+  window.scrollTo(0, 0);
+  window.scrollBy({ left: 30, top: 40 });
+  testing.expectEqual(30, window.scrollX);
+  testing.expectEqual(40, window.scrollY);
+</script>
+
+<script id=scrollBy_negative_clamp>
+  window.scrollTo(10, 10);
+  window.scrollBy(-100, -100);
+  testing.expectEqual(0, window.scrollX);
+  testing.expectEqual(0, window.scrollY);
+</script>

src/browser/tests/xmlserializer.html

@@ -129,3 +129,14 @@
   testing.expectEqual(original, serialized);
 }
 </script>
+
+<script id=serializeAttribute>
+{
+  const div = document.createElement('div');
+  div.setAttribute('over', '9000');
+
+  const serializer = new XMLSerializer();
+  const serialized = serializer.serializeToString(div.getAttributeNode('over'));
+  testing.expectEqual('', serialized);
+}
+</script>

src/browser/webapi/AbortController.zig

@@ -38,7 +38,7 @@ pub fn getSignal(self: *const AbortController) *AbortSignal {
 }
 
 pub fn abort(self: *AbortController, reason_: ?js.Value.Global, page: *Page) !void {
-    try self._signal.abort(if (reason_) |r| .{ .js_val = r } else null, page.js.local.?, page);
+    try self._signal.abort(if (reason_) |r| .{ .js_val = r } else null, page);
 }
 
 pub const JsApi = struct {