Merge pull request #1560 from arrufat/dump-markdown

Add support for dumping output to markdown

.github/actions/install/action.yml

@@ -13,7 +13,7 @@ inputs:
   zig-v8:
     description: 'zig v8 version to install'
     required: false
-    default: 'v0.2.6'
+    default: 'v0.2.9'
   v8:
     description: 'v8 version to install'
     required: false
@@ -22,6 +22,10 @@ inputs:
     description: 'cache dir to use'
     required: false
     default: '~/.cache'
+  debug:
+    description: 'enable v8 pre-built debug version, only available for linux x86_64'
+    required: false
+    default: 'false'
 
 runs:
   using: "composite"
@@ -47,17 +51,17 @@ runs:
         cache-name: cache-v8
       with:
         path: ${{ inputs.cache-dir }}/v8
-        key: libc_v8_${{ inputs.v8 }}_${{ inputs.os }}_${{ inputs.arch }}_${{ inputs.zig-v8 }}.a
+        key: libc_v8_${{ inputs.v8 }}_${{ inputs.os }}_${{ inputs.arch }}_${{ inputs.zig-v8 }}${{inputs.debug == 'true' && '_debug' || '' }}.a
 
     - if: ${{ steps.cache-v8.outputs.cache-hit != 'true' }}
       shell: bash
       run: |
         mkdir -p ${{ inputs.cache-dir }}/v8
 
-        wget -O ${{ inputs.cache-dir }}/v8/libc_v8.a https://github.com/lightpanda-io/zig-v8-fork/releases/download/${{ inputs.zig-v8 }}/libc_v8_${{ inputs.v8 }}_${{ inputs.os }}_${{ inputs.arch }}.a
+        wget -O ${{ inputs.cache-dir }}/v8/libc_v8.a https://github.com/lightpanda-io/zig-v8-fork/releases/download/${{ inputs.zig-v8 }}/libc_v8_${{ inputs.v8 }}_${{ inputs.os }}_${{ inputs.arch }}${{inputs.debug == 'true' && '_debug' || '' }}.a
 
     - name: install v8
       shell: bash
       run: |
         mkdir -p v8
-        ln -s ${{ inputs.cache-dir }}/v8/libc_v8.a v8/libc_v8.a
+        ln -s ${{ inputs.cache-dir }}/v8/libc_v8.a v8/libc_v8${{inputs.debug == 'true' && '_debug' || '' }}.a

.github/workflows/build.yml

@@ -40,7 +40,6 @@ jobs:
         with:
           os: ${{env.OS}}
           arch: ${{env.ARCH}}
-          mode: 'release'
 
       - name: v8 snapshot
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
@@ -83,7 +82,6 @@ jobs:
         with:
           os: ${{env.OS}}
           arch: ${{env.ARCH}}
-          mode: 'release'
 
       - name: v8 snapshot
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
@@ -128,7 +126,6 @@ jobs:
         with:
           os: ${{env.OS}}
           arch: ${{env.ARCH}}
-          mode: 'release'
 
       - name: v8 snapshot
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
@@ -171,7 +168,6 @@ jobs:
         with:
           os: ${{env.OS}}
           arch: ${{env.ARCH}}
-          mode: 'release'
 
       - name: v8 snapshot
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin

.github/workflows/e2e-test.yml

@@ -56,8 +56,6 @@ jobs:
           submodules: recursive
 
       - uses: ./.github/actions/install
-        with:
-          mode: 'release'
 
       - 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 }})
@@ -124,10 +122,19 @@ jobs:
     needs: zig-build-release
 
     env:
-      MAX_MEMORY: 26000
+      MAX_VmHWM: 28000 # 28MB (KB)
+      MAX_CG_PEAK: 8000 # 8MB (KB)
       MAX_AVG_DURATION: 17
       LIGHTPANDA_DISABLE_TELEMETRY: true
 
+      # How to give cgroups access to the user actions-runner on the host:
+      # $ sudo apt install cgroup-tools
+      # $ sudo chmod o+w /sys/fs/cgroup/cgroup.procs
+      # $ sudo mkdir -p /sys/fs/cgroup/actions-runner
+      # $ sudo chown -R actions-runner:actions-runner /sys/fs/cgroup/actions-runner
+      CG_ROOT: /sys/fs/cgroup
+      CG: actions-runner/lpd_${{ github.run_id }}_${{ github.run_attempt }}
+
     # use a self host runner.
     runs-on: lpd-bench-hetzner
     timeout-minutes: 15
@@ -152,22 +159,53 @@ jobs:
           go run ws/main.go & echo $! > WS.pid
           sleep 2
 
+      - name: run lightpanda in cgroup
+        run: |
+          if [ ! -f /sys/fs/cgroup/cgroup.controllers ]; then
+            echo "cgroup v2 not available: /sys/fs/cgroup/cgroup.controllers missing"
+            exit 1
+          fi
+
+          mkdir -p $CG_ROOT/$CG
+          cgexec -g memory:$CG ./lightpanda serve & echo $! > LPD.pid
+
+          sleep 2
+
       - name: run puppeteer
         run: |
-          ./lightpanda serve & echo $! > LPD.pid
-          sleep 2
           RUNS=100 npm run bench-puppeteer-cdp > puppeteer.out || exit 1
           cat /proc/`cat LPD.pid`/status |grep VmHWM|grep -oP '\d+' > LPD.VmHWM
           kill `cat LPD.pid`
 
+          PID=$(cat LPD.pid)
+          while kill -0 $PID 2>/dev/null; do
+            sleep 1
+          done
+          if [ ! -f $CG_ROOT/$CG/memory.peak ]; then
+            echo "memory.peak not available in $CG"
+            exit 1
+          fi
+          cat $CG_ROOT/$CG/memory.peak > LPD.cg_mem_peak
+
       - name: puppeteer result
         run: cat puppeteer.out
 
-      - name: memory regression
+      - name: cgroup memory regression
+        run: |
+          PEAK_BYTES=$(cat LPD.cg_mem_peak)
+          PEAK_KB=$((PEAK_BYTES / 1024))
+          echo "memory.peak_bytes=$PEAK_BYTES"
+          echo "memory.peak_kb=$PEAK_KB"
+          test "$PEAK_KB" -le "$MAX_CG_PEAK"
+
+      - name: virtual memory regression
         run: |
           export LPD_VmHWM=`cat LPD.VmHWM`
           echo "Peak resident set size: $LPD_VmHWM"
-          test "$LPD_VmHWM" -le "$MAX_MEMORY"
+          test "$LPD_VmHWM" -le "$MAX_VmHWM"
+
+      - name: cleanup cgroup
+        run: rmdir $CG_ROOT/$CG
 
       - name: duration regression
         run: |
@@ -180,7 +218,8 @@ jobs:
           export AVG_DURATION=`cat puppeteer.out|grep 'avg run'|sed 's/avg run duration (ms) //'`
           export TOTAL_DURATION=`cat puppeteer.out|grep 'total duration'|sed 's/total duration (ms) //'`
           export LPD_VmHWM=`cat LPD.VmHWM`
-          echo "{\"duration_total\":${TOTAL_DURATION},\"duration_avg\":${AVG_DURATION},\"mem_peak\":${LPD_VmHWM}}" > bench.json
+          export LPD_CG_PEAK_KB=$(( $(cat LPD.cg_mem_peak) / 1024 ))
+          echo "{\"duration_total\":${TOTAL_DURATION},\"duration_avg\":${AVG_DURATION},\"mem_peak\":${LPD_VmHWM},\"cg_mem_peak\":${LPD_CG_PEAK_KB}}" > bench.json
           cat bench.json
 
       - name: run hyperfine

.github/workflows/zig-test.yml

@@ -12,8 +12,7 @@ on:
       - main
     paths:
       - "build.zig"
-      - "src/**/*.zig"
-      - "src/*.zig"
+      - "src/**"
       - "vendor/zig-js-runtime"
       - ".github/**"
       - "vendor/**"
@@ -38,6 +37,26 @@ on:
   workflow_dispatch:
 
 jobs:
+  zig-test-debug:
+    name: zig test using v8 in debug mode
+    timeout-minutes: 15
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          # fetch submodules recusively, to get zig-js-runtime submodules also.
+          submodules: recursive
+
+      - uses: ./.github/actions/install
+        with:
+          debug: true
+
+      - name: zig build test
+        run: zig build -Dprebuilt_v8_path=v8/libc_v8_debug.a -Dtsan=true test
+
   zig-test:
     name: zig test
     timeout-minutes: 15

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=v0.2.6
+ARG ZIG_V8=v0.2.9
 ARG TARGETPLATFORM
 
 RUN apt-get update -yq && \

Makefile

@@ -57,7 +57,7 @@ build-v8-snapshot:
 
 ## Build in release-fast mode
 build: build-v8-snapshot
-	@printf "\033[36mBuilding (release safe)...\033[0m\n"
+	@printf "\033[36mBuilding (release fast)...\033[0m\n"
 	@$(ZIG) build -Doptimize=ReleaseFast -Dsnapshot_path=../../snapshot.bin -Dgit_commit=$$(git rev-parse --short HEAD) || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
 	@printf "\033[33mBuild OK\033[0m\n"
 

README.md

@@ -78,23 +78,49 @@ docker run -d --name lightpanda -p 9222:9222 lightpanda/browser:nightly
 ### Dump a URL
 
 ```console
-./lightpanda fetch --dump https://lightpanda.io
+./lightpanda fetch --obey_robots --log_format pretty  --log_level info https://demo-browser.lightpanda.io/campfire-commerce/
 ```
 ```console
-info(browser): GET https://lightpanda.io/ http.Status.ok
-info(browser): fetch script https://api.website.lightpanda.io/js/script.js: http.Status.ok
-info(browser): eval remote https://api.website.lightpanda.io/js/script.js: TypeError: Cannot read properties of undefined (reading 'pushState')
+INFO  telemetry : telemetry status . . . . . . . . . . . . .  [+0ms]
+      disabled = false
+
+INFO  page : navigate . . . . . . . . . . . . . . . . . . . . [+6ms]
+      url = https://demo-browser.lightpanda.io/campfire-commerce/
+      method = GET
+      reason = address_bar
+      body = false
+      req_id = 1
+
+INFO  browser : executing script . . . . . . . . . . . . . .  [+118ms]
+      src = https://demo-browser.lightpanda.io/campfire-commerce/script.js
+      kind = javascript
+      cacheable = true
+
+INFO  http : request complete . . . . . . . . . . . . . . . . [+140ms]
+      source = xhr
+      url = https://demo-browser.lightpanda.io/campfire-commerce/json/product.json
+      status = 200
+      len = 4770
+
+INFO  http : request complete . . . . . . . . . . . . . . . . [+141ms]
+      source = fetch
+      url = https://demo-browser.lightpanda.io/campfire-commerce/json/reviews.json
+      status = 200
+      len = 1615
 <!DOCTYPE html>
 ```
 
 ### Start a CDP server
 
 ```console
-./lightpanda serve --host 127.0.0.1 --port 9222
+./lightpanda serve --obey_robots --log_format pretty  --log_level info --host 127.0.0.1 --port 9222
 ```
 ```console
-info(websocket): starting blocking worker to listen on 127.0.0.1:9222
-info(server): accepting new conn...
+INFO  telemetry : telemetry status . . . . . . . . . . . . .  [+0ms]
+      disabled = false
+
+INFO  app : server running . . . . . . . . . . . . . . . . .  [+0ms]
+      address = 127.0.0.1:9222
 ```
 
 Once the CDP server started, you can run a Puppeteer script by configuring the
@@ -115,7 +141,7 @@ const context = await browser.createBrowserContext();
 const page = await context.newPage();
 
 // Dump all the links from the page.
-await page.goto('https://wikipedia.com/');
+await page.goto('https://demo-browser.lightpanda.io/amiibo/', {waitUntil: "networkidle0"});
 
 const links = await page.evaluate(() => {
   return Array.from(document.querySelectorAll('a')).map(row => {
@@ -156,6 +182,7 @@ Here are the key features we have implemented:
 - [x] Custom HTTP headers
 - [x] Proxy support
 - [x] Network interception
+- [x] Respect `robots.txt` with option `--obey_robots`
 
 NOTE: There are hundreds of Web APIs. Developing a browser (even just for headless mode) is a huge task. Coverage will increase over time.
 

build.zig

@@ -35,7 +35,8 @@ pub fn build(b: *Build) !void {
     opts.addOption([]const u8, "git_commit", git_commit orelse "dev");
     opts.addOption(?[]const u8, "snapshot_path", snapshot_path);
 
-    const enable_tsan = b.option(bool, "tsan", "Enable Thread Sanitizer");
+    const enable_tsan = b.option(bool, "tsan", "Enable Thread Sanitizer") orelse false;
+    const enable_asan = b.option(bool, "asan", "Enable Address Sanitizer") orelse false;
     const enable_csan = b.option(std.zig.SanitizeC, "csan", "Enable C Sanitizers");
 
     const lightpanda_module = blk: {
@@ -50,7 +51,7 @@ pub fn build(b: *Build) !void {
         });
         mod.addImport("lightpanda", mod); // allow circular "lightpanda" import
 
-        try addDependencies(b, mod, opts, prebuilt_v8_path);
+        try addDependencies(b, mod, opts, enable_asan, enable_tsan, prebuilt_v8_path);
 
         break :blk mod;
     };
@@ -170,15 +171,25 @@ pub fn build(b: *Build) !void {
     }
 }
 
-fn addDependencies(b: *Build, mod: *Build.Module, opts: *Build.Step.Options, prebuilt_v8_path: ?[]const u8) !void {
+fn addDependencies(
+    b: *Build,
+    mod: *Build.Module,
+    opts: *Build.Step.Options,
+    is_asan: bool,
+    is_tsan: bool,
+    prebuilt_v8_path: ?[]const u8,
+) !void {
     mod.addImport("build_config", opts.createModule());
 
     const target = mod.resolved_target.?;
     const dep_opts = .{
         .target = target,
         .optimize = mod.optimize.?,
-        .prebuilt_v8_path = prebuilt_v8_path,
         .cache_root = b.pathFromRoot(".lp-cache"),
+        .prebuilt_v8_path = prebuilt_v8_path,
+        .is_asan = is_asan,
+        .is_tsan = is_tsan,
+        .v8_enable_sandbox = is_tsan,
     };
 
     mod.addIncludePath(b.path("vendor/lightpanda"));

build.zig.zon

@@ -6,8 +6,8 @@
     .minimum_zig_version = "0.15.2",
     .dependencies = .{
         .v8 = .{
-            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/v0.2.6.tar.gz",
-            .hash = "v8-0.0.0-xddH60NRBAAWmpZq9nWdfFAEqVJ9zqJnvr1Nl9m2AbcY",
+            .url = "https://github.com/lightpanda-io/zig-v8-fork/archive/refs/tags/v0.2.9.tar.gz",
+            .hash = "v8-0.0.0-xddH689vBACgpqFVEhT2wxRin-qQQSOcKJoM37MVo0rU",
         },
         //.v8 = .{ .path = "../zig-v8-fork" },
         .@"boringssl-zig" = .{

flake.lock

@@ -8,11 +8,11 @@
         "rust-analyzer-src": "rust-analyzer-src"
       },
       "locked": {
-        "lastModified": 1763016383,
-        "narHash": "sha256-eYmo7FNvm3q08iROzwIi8i9dWuUbJJl3uLR3OLnSmdI=",
+        "lastModified": 1770708269,
+        "narHash": "sha256-OnZW86app7hHJJoB5lC9GNXY5QBBIESJB+sIdwEyld0=",
         "owner": "nix-community",
         "repo": "fenix",
-        "rev": "0fad5c0e5c531358e7174cd666af4608f08bc3ba",
+        "rev": "6b5325a017a9a9fe7e6252ccac3680cc7181cd63",
         "type": "github"
       },
       "original": {
@@ -96,11 +96,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1763043403,
-        "narHash": "sha256-DgCTbHdIpzbXSlQlOZEWj8oPt2lrRMlSk03oIstvkVQ=",
+        "lastModified": 1768649915,
+        "narHash": "sha256-jc21hKogFnxU7KXSVTRmxC7u5D4RHwm9BAvDf5/Z1Uo=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "75e04ecd084f93d4105ce68c07dac7656291fe2e",
+        "rev": "3e3f3c7f9977dc123c23ee21e8085ed63daf8c37",
         "type": "github"
       },
       "original": {
@@ -122,11 +122,11 @@
     "rust-analyzer-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1762860488,
-        "narHash": "sha256-rMfWMCOo/pPefM2We0iMBLi2kLBAnYoB9thi4qS7uk4=",
+        "lastModified": 1770668050,
+        "narHash": "sha256-Q05yaIZtQrBKHpyWaPmyJmDRj0lojnVf8nUFE0vydcY=",
         "owner": "rust-lang",
         "repo": "rust-analyzer",
-        "rev": "2efc80078029894eec0699f62ec8d5c1a56af763",
+        "rev": "9efc1f709f3c8134c3acac5d3592a8e4c184a0c6",
         "type": "github"
       },
       "original": {
@@ -175,11 +175,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1762907712,
-        "narHash": "sha256-VNW/+VYIg6N4b9Iq+F0YZmm22n74IdFS7hsPLblWuOY=",
+        "lastModified": 1770598090,
+        "narHash": "sha256-k+82IDgTd9o5sxHIqGlvfwseKln3Ejx1edGtDltuPXo=",
         "owner": "mitchellh",
         "repo": "zig-overlay",
-        "rev": "d16453ee78765e49527c56d23386cead799b6b53",
+        "rev": "142495696982c88edddc8e17e4da90d8164acadf",
         "type": "github"
       },
       "original": {

src/App.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -21,68 +21,38 @@ const std = @import("std");
 const Allocator = std.mem.Allocator;
 
 const log = @import("log.zig");
+const Config = @import("Config.zig");
 const Snapshot = @import("browser/js/Snapshot.zig");
 const Platform = @import("browser/js/Platform.zig");
 const Telemetry = @import("telemetry/telemetry.zig").Telemetry;
+const RobotStore = @import("browser/Robots.zig").RobotStore;
 
 pub const Http = @import("http/Http.zig");
 pub const ArenaPool = @import("ArenaPool.zig");
-pub const Notification = @import("Notification.zig");
 
-// Container for global state / objects that various parts of the system
-// might need.
 const App = @This();
 
 http: Http,
-config: Config,
+config: *const Config,
 platform: Platform,
 snapshot: Snapshot,
 telemetry: Telemetry,
 allocator: Allocator,
 arena_pool: ArenaPool,
+robots: RobotStore,
 app_dir_path: ?[]const u8,
-notification: *Notification,
 shutdown: bool = false,
 
-pub const RunMode = enum {
-    help,
-    fetch,
-    serve,
-    version,
-};
-
-pub const Config = struct {
-    run_mode: RunMode,
-    tls_verify_host: bool = true,
-    http_proxy: ?[:0]const u8 = null,
-    proxy_bearer_token: ?[:0]const u8 = null,
-    http_timeout_ms: ?u31 = null,
-    http_connect_timeout_ms: ?u31 = null,
-    http_max_host_open: ?u8 = null,
-    http_max_concurrent: ?u8 = null,
-    user_agent: [:0]const u8,
-};
-
-pub fn init(allocator: Allocator, config: Config) !*App {
+pub fn init(allocator: Allocator, config: *const Config) !*App {
     const app = try allocator.create(App);
     errdefer allocator.destroy(app);
 
     app.config = config;
     app.allocator = allocator;
 
-    app.notification = try Notification.init(allocator, null);
-    errdefer app.notification.deinit();
+    app.robots = RobotStore.init(allocator);
 
-    app.http = try Http.init(allocator, .{
-        .max_host_open = config.http_max_host_open orelse 4,
-        .max_concurrent = config.http_max_concurrent orelse 10,
-        .timeout_ms = config.http_timeout_ms orelse 5000,
-        .connect_timeout_ms = config.http_connect_timeout_ms orelse 0,
-        .http_proxy = config.http_proxy,
-        .tls_verify_host = config.tls_verify_host,
-        .proxy_bearer_token = config.proxy_bearer_token,
-        .user_agent = config.user_agent,
-    });
+    app.http = try Http.init(allocator, &app.robots, config);
     errdefer app.http.deinit();
 
     app.platform = try Platform.init();
@@ -93,11 +63,9 @@ pub fn init(allocator: Allocator, config: Config) !*App {
 
     app.app_dir_path = getAndMakeAppDir(allocator);
 
-    app.telemetry = try Telemetry.init(app, config.run_mode);
+    app.telemetry = try Telemetry.init(app, config.mode);
     errdefer app.telemetry.deinit();
 
-    try app.telemetry.register(app.notification);
-
     app.arena_pool = ArenaPool.init(allocator);
     errdefer app.arena_pool.deinit();
 
@@ -115,7 +83,7 @@ pub fn deinit(self: *App) void {
         self.app_dir_path = null;
     }
     self.telemetry.deinit();
-    self.notification.deinit();
+    self.robots.deinit();
     self.http.deinit();
     self.snapshot.deinit();
     self.platform.deinit();

src/ArenaPool.zig

@@ -29,6 +29,7 @@ free_list_len: u16 = 0,
 free_list: ?*Entry = null,
 free_list_max: u16,
 entry_pool: std.heap.MemoryPool(Entry),
+mutex: std.Thread.Mutex = .{},
 
 const Entry = struct {
     next: ?*Entry,
@@ -54,8 +55,12 @@ pub fn deinit(self: *ArenaPool) void {
 }
 
 pub fn acquire(self: *ArenaPool) !Allocator {
+    self.mutex.lock();
+    defer self.mutex.unlock();
+
     if (self.free_list) |entry| {
         self.free_list = entry.next;
+        self.free_list_len -= 1;
         return entry.arena.allocator();
     }
 
@@ -72,13 +77,25 @@ pub fn release(self: *ArenaPool, allocator: Allocator) void {
     const arena: *std.heap.ArenaAllocator = @ptrCast(@alignCast(allocator.ptr));
     const entry: *Entry = @fieldParentPtr("arena", arena);
 
-    if (self.free_list_len == self.free_list_max) {
+    // Reset the arena before acquiring the lock to minimize lock hold time
+    _ = arena.reset(.{ .retain_with_limit = self.retain_bytes });
+
+    self.mutex.lock();
+    defer self.mutex.unlock();
+
+    const free_list_len = self.free_list_len;
+    if (free_list_len == self.free_list_max) {
         arena.deinit();
         self.entry_pool.destroy(entry);
         return;
     }
 
-    _ = arena.reset(.{ .retain_with_limit = self.retain_bytes });
     entry.next = self.free_list;
+    self.free_list_len = free_list_len + 1;
     self.free_list = entry;
 }
+
+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 });
+}

src/Config.zig

@@ -0,0 +1,802 @@
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+const builtin = @import("builtin");
+const Allocator = std.mem.Allocator;
+
+const log = @import("log.zig");
+const dump = @import("browser/dump.zig");
+
+pub const RunMode = enum {
+    help,
+    fetch,
+    serve,
+    version,
+};
+
+pub const CDP_MAX_HTTP_REQUEST_SIZE = 4096;
+
+// max message size
+// +14 for max websocket payload overhead
+// +140 for the max control packet that might be interleaved in a message
+pub const CDP_MAX_MESSAGE_SIZE = 512 * 1024 + 14 + 140;
+
+mode: Mode,
+exec_name: []const u8,
+http_headers: HttpHeaders,
+
+const Config = @This();
+
+pub fn init(allocator: Allocator, exec_name: []const u8, mode: Mode) !Config {
+    var config = Config{
+        .mode = mode,
+        .exec_name = exec_name,
+        .http_headers = undefined,
+    };
+    config.http_headers = try HttpHeaders.init(allocator, &config);
+    return config;
+}
+
+pub fn deinit(self: *const Config, allocator: Allocator) void {
+    self.http_headers.deinit(allocator);
+}
+
+pub fn tlsVerifyHost(self: *const Config) bool {
+    return switch (self.mode) {
+        inline .serve, .fetch => |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,
+        else => unreachable,
+    };
+}
+
+pub fn httpProxy(self: *const Config) ?[:0]const u8 {
+    return switch (self.mode) {
+        inline .serve, .fetch => |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,
+        .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,
+        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,
+        else => unreachable,
+    };
+}
+
+pub fn httpConnectTimeout(self: *const Config) u31 {
+    return switch (self.mode) {
+        inline .serve, .fetch => |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,
+        else => unreachable,
+    };
+}
+
+pub fn httpMaxRedirects(_: *const Config) u8 {
+    return 10;
+}
+
+pub fn httpMaxResponseSize(self: *const Config) ?usize {
+    return switch (self.mode) {
+        inline .serve, .fetch => |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,
+        else => unreachable,
+    };
+}
+
+pub fn logFormat(self: *const Config) ?log.Format {
+    return switch (self.mode) {
+        inline .serve, .fetch => |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,
+        else => unreachable,
+    };
+}
+
+pub fn userAgentSuffix(self: *const Config) ?[]const u8 {
+    return switch (self.mode) {
+        inline .serve, .fetch => |opts| opts.common.user_agent_suffix,
+        .help, .version => null,
+    };
+}
+
+pub fn maxConnections(self: *const Config) u16 {
+    return switch (self.mode) {
+        .serve => |opts| opts.cdp_max_connections,
+        else => unreachable,
+    };
+}
+
+pub fn maxPendingConnections(self: *const Config) u31 {
+    return switch (self.mode) {
+        .serve => |opts| opts.cdp_max_pending_connections,
+        else => unreachable,
+    };
+}
+
+pub const Mode = union(RunMode) {
+    help: bool, // false when being printed because of an error
+    fetch: Fetch,
+    serve: Serve,
+    version: void,
+};
+
+pub const Serve = struct {
+    host: []const u8 = "127.0.0.1",
+    port: u16 = 9222,
+    timeout: u31 = 10,
+    cdp_max_connections: u16 = 16,
+    cdp_max_pending_connections: u16 = 128,
+    common: Common = .{},
+};
+
+pub const DumpFormat = enum {
+    html,
+    markdown,
+};
+
+pub const Fetch = struct {
+    url: [:0]const u8,
+    dump_mode: ?DumpFormat = null,
+    common: Common = .{},
+    withbase: bool = false,
+    strip: dump.Opts.Strip = .{},
+};
+
+pub const Common = struct {
+    obey_robots: bool = false,
+    proxy_bearer_token: ?[:0]const u8 = null,
+    http_proxy: ?[:0]const u8 = null,
+    http_max_concurrent: ?u8 = null,
+    http_max_host_open: ?u8 = null,
+    http_timeout: ?u31 = null,
+    http_connect_timeout: ?u31 = null,
+    http_max_response_size: ?usize = null,
+    tls_verify_host: bool = true,
+    log_level: ?log.Level = null,
+    log_format: ?log.Format = null,
+    log_filter_scopes: ?[]log.Scope = null,
+    user_agent_suffix: ?[]const u8 = null,
+};
+
+/// Pre-formatted HTTP headers for reuse across Http and Client.
+/// Must be initialized with an allocator that outlives all HTTP connections.
+pub const HttpHeaders = struct {
+    const user_agent_base: [:0]const u8 = "Lightpanda/1.0";
+
+    user_agent: [:0]const u8, // User agent value (e.g. "Lightpanda/1.0")
+    user_agent_header: [:0]const u8,
+
+    proxy_bearer_header: ?[:0]const u8,
+
+    pub fn init(allocator: Allocator, config: *const Config) !HttpHeaders {
+        const user_agent: [:0]const u8 = if (config.userAgentSuffix()) |suffix|
+            try std.fmt.allocPrintSentinel(allocator, "{s} {s}", .{ user_agent_base, suffix }, 0)
+        else
+            user_agent_base;
+        errdefer if (config.userAgentSuffix() != null) allocator.free(user_agent);
+
+        const user_agent_header = try std.fmt.allocPrintSentinel(allocator, "User-Agent: {s}", .{user_agent}, 0);
+        errdefer allocator.free(user_agent_header);
+
+        const proxy_bearer_header: ?[:0]const u8 = if (config.proxyBearerToken()) |token|
+            try std.fmt.allocPrintSentinel(allocator, "Proxy-Authorization: Bearer {s}", .{token}, 0)
+        else
+            null;
+
+        return .{
+            .user_agent = user_agent,
+            .user_agent_header = user_agent_header,
+            .proxy_bearer_header = proxy_bearer_header,
+        };
+    }
+
+    pub fn deinit(self: *const HttpHeaders, allocator: Allocator) void {
+        if (self.proxy_bearer_header) |hdr| {
+            allocator.free(hdr);
+        }
+        allocator.free(self.user_agent_header);
+        if (self.user_agent.ptr != user_agent_base.ptr) {
+            allocator.free(self.user_agent);
+        }
+    }
+};
+
+pub fn printUsageAndExit(self: *const Config, success: bool) void {
+    //                                                                     MAX_HELP_LEN|
+    const common_options =
+        \\
+        \\--insecure_disable_tls_host_verification
+        \\                Disables host verification on all HTTP requests. This is an
+        \\                advanced option which should only be set if you understand
+        \\                and accept the risk of disabling host verification.
+        \\
+        \\--obey_robots
+        \\                Fetches and obeys the robots.txt (if available) of the web pages
+        \\                we make requests towards.
+        \\                Defaults to false.
+        \\
+        \\--http_proxy    The HTTP proxy to use for all HTTP requests.
+        \\                A username:password can be included for basic authentication.
+        \\                Defaults to none.
+        \\
+        \\--proxy_bearer_token
+        \\                The <token> to send for bearer authentication with the proxy
+        \\                Proxy-Authorization: Bearer <token>
+        \\
+        \\--http_max_concurrent
+        \\                The maximum number of concurrent HTTP requests.
+        \\                Defaults to 10.
+        \\
+        \\--http_max_host_open
+        \\                The maximum number of open connection to a given host:port.
+        \\                Defaults to 4.
+        \\
+        \\--http_connect_timeout
+        \\                The time, in milliseconds, for establishing an HTTP connection
+        \\                before timing out. 0 means it never times out.
+        \\                Defaults to 0.
+        \\
+        \\--http_timeout
+        \\                The maximum time, in milliseconds, the transfer is allowed
+        \\                to complete. 0 means it never times out.
+        \\                Defaults to 10000.
+        \\
+        \\--http_max_response_size
+        \\                Limits the acceptable response size for any request
+        \\                (e.g. XHR, fetch, script loading, ...).
+        \\                Defaults to no limit.
+        \\
+        \\--log_level     The log level: debug, info, warn, error or fatal.
+        \\                Defaults to
+    ++ (if (builtin.mode == .Debug) " info." else "warn.") ++
+        \\
+        \\
+        \\--log_format    The log format: pretty or logfmt.
+        \\                Defaults to
+    ++ (if (builtin.mode == .Debug) " pretty." else " logfmt.") ++
+        \\
+        \\
+        \\--log_filter_scopes
+        \\                Filter out too verbose logs per scope:
+        \\                http, unknown_prop, event, ...
+        \\
+        \\--user_agent_suffix
+        \\                Suffix to append to the Lightpanda/X.Y User-Agent
+        \\
+    ;
+
+    //                                                                     MAX_HELP_LEN|
+    const usage =
+        \\usage: {s} command [options] [URL]
+        \\
+        \\Command can be either 'fetch', 'serve' or 'help'
+        \\
+        \\fetch command
+        \\Fetches the specified URL
+        \\Example: {s} fetch --dump html https://lightpanda.io/
+        \\
+        \\Options:
+        \\--dump          Dumps document to stdout.
+        \\                Argument must be 'html' or 'markdown'.
+        \\                Defaults to no dump.
+        \\
+        \\--strip_mode    Comma separated list of tag groups to remove from dump
+        \\                the dump. e.g. --strip_mode js,css
+        \\                  - "js" script and link[as=script, rel=preload]
+        \\                  - "ui" includes img, picture, video, css and svg
+        \\                  - "css" includes style and link[rel=stylesheet]
+        \\                  - "full" includes js, ui and css
+        \\
+        \\--with_base     Add a <base> tag in dump. Defaults to false.
+        \\
+    ++ common_options ++
+        \\
+        \\serve command
+        \\Starts a websocket CDP server
+        \\Example: {s} serve --host 127.0.0.1 --port 9222
+        \\
+        \\Options:
+        \\--host          Host of the CDP server
+        \\                Defaults to "127.0.0.1"
+        \\
+        \\--port          Port of the CDP server
+        \\                Defaults to 9222
+        \\
+        \\--timeout       Inactivity timeout in seconds before disconnecting clients
+        \\                Defaults to 10 (seconds). Limited to 604800 (1 week).
+        \\
+        \\--cdp_max_connections
+        \\                Maximum number of simultaneous CDP connections.
+        \\                Defaults to 16.
+        \\
+        \\--cdp_max_pending_connections
+        \\                Maximum pending connections in the accept queue.
+        \\                Defaults to 128.
+        \\
+    ++ common_options ++
+        \\
+        \\version command
+        \\Displays the version of {s}
+        \\
+        \\help command
+        \\Displays this message
+        \\
+    ;
+    std.debug.print(usage, .{ self.exec_name, self.exec_name, self.exec_name, self.exec_name });
+    if (success) {
+        return std.process.cleanExit();
+    }
+    std.process.exit(1);
+}
+
+pub fn parseArgs(allocator: Allocator) !Config {
+    var args = try std.process.argsWithAllocator(allocator);
+    defer args.deinit();
+
+    const exec_name = try allocator.dupe(u8, std.fs.path.basename(args.next().?));
+
+    const mode_string = args.next() orelse "";
+    const run_mode = std.meta.stringToEnum(RunMode, mode_string) orelse blk: {
+        const inferred_mode = inferMode(mode_string) orelse
+            return init(allocator, exec_name, .{ .help = false });
+        // "command" wasn't a command but an option. We can't reset args, but
+        // we can create a new one. Not great, but this fallback is temporary
+        // as we transition to this command mode approach.
+        args.deinit();
+
+        args = try std.process.argsWithAllocator(allocator);
+        // skip the exec_name
+        _ = args.skip();
+
+        break :blk inferred_mode;
+    };
+
+    const mode: Mode = switch (run_mode) {
+        .help => .{ .help = true },
+        .serve => .{ .serve = parseServeArgs(allocator, &args) catch
+            return init(allocator, exec_name, .{ .help = false }) },
+        .fetch => .{ .fetch = parseFetchArgs(allocator, &args) catch
+            return init(allocator, exec_name, .{ .help = false }) },
+        .version => .{ .version = {} },
+    };
+    return init(allocator, exec_name, mode);
+}
+
+fn inferMode(opt: []const u8) ?RunMode {
+    if (opt.len == 0) {
+        return .serve;
+    }
+
+    if (std.mem.startsWith(u8, opt, "--") == false) {
+        return .fetch;
+    }
+
+    if (std.mem.eql(u8, opt, "--dump")) {
+        return .fetch;
+    }
+
+    if (std.mem.eql(u8, opt, "--noscript")) {
+        return .fetch;
+    }
+
+    if (std.mem.eql(u8, opt, "--strip_mode")) {
+        return .fetch;
+    }
+
+    if (std.mem.eql(u8, opt, "--with_base")) {
+        return .fetch;
+    }
+
+    if (std.mem.eql(u8, opt, "--host")) {
+        return .serve;
+    }
+
+    if (std.mem.eql(u8, opt, "--port")) {
+        return .serve;
+    }
+
+    if (std.mem.eql(u8, opt, "--timeout")) {
+        return .serve;
+    }
+
+    return null;
+}
+
+fn parseServeArgs(
+    allocator: Allocator,
+    args: *std.process.ArgIterator,
+) !Serve {
+    var serve: Serve = .{};
+
+    while (args.next()) |opt| {
+        if (std.mem.eql(u8, "--host", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--host" });
+                return error.InvalidArgument;
+            };
+            serve.host = try allocator.dupe(u8, str);
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--port", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--port" });
+                return error.InvalidArgument;
+            };
+
+            serve.port = std.fmt.parseInt(u16, str, 10) catch |err| {
+                log.fatal(.app, "invalid argument value", .{ .arg = "--port", .err = err });
+                return error.InvalidArgument;
+            };
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--timeout", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--timeout" });
+                return error.InvalidArgument;
+            };
+
+            serve.timeout = std.fmt.parseInt(u31, str, 10) catch |err| {
+                log.fatal(.app, "invalid argument value", .{ .arg = "--timeout", .err = err });
+                return error.InvalidArgument;
+            };
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--cdp_max_connections", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--cdp_max_connections" });
+                return error.InvalidArgument;
+            };
+
+            serve.cdp_max_connections = std.fmt.parseInt(u16, str, 10) catch |err| {
+                log.fatal(.app, "invalid argument value", .{ .arg = "--cdp_max_connections", .err = err });
+                return error.InvalidArgument;
+            };
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--cdp_max_pending_connections", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--cdp_max_pending_connections" });
+                return error.InvalidArgument;
+            };
+
+            serve.cdp_max_pending_connections = std.fmt.parseInt(u16, str, 10) catch |err| {
+                log.fatal(.app, "invalid argument value", .{ .arg = "--cdp_max_pending_connections", .err = err });
+                return error.InvalidArgument;
+            };
+            continue;
+        }
+
+        if (try parseCommonArg(allocator, opt, args, &serve.common)) {
+            continue;
+        }
+
+        log.fatal(.app, "unknown argument", .{ .mode = "serve", .arg = opt });
+        return error.UnkownOption;
+    }
+
+    return serve;
+}
+
+fn parseFetchArgs(
+    allocator: Allocator,
+    args: *std.process.ArgIterator,
+) !Fetch {
+    var dump_mode: ?DumpFormat = null;
+    var withbase: bool = false;
+    var url: ?[:0]const u8 = null;
+    var common: Common = .{};
+    var strip: dump.Opts.Strip = .{};
+
+    while (args.next()) |opt| {
+        if (std.mem.eql(u8, "--dump", opt)) {
+            var peek_args = args.*;
+            if (peek_args.next()) |next_arg| {
+                if (std.meta.stringToEnum(DumpFormat, next_arg)) |mode| {
+                    dump_mode = mode;
+                    _ = args.next();
+                } else {
+                    dump_mode = .html;
+                }
+            } else {
+                dump_mode = .html;
+            }
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--noscript", opt)) {
+            log.warn(.app, "deprecation warning", .{
+                .feature = "--noscript argument",
+                .hint = "use '--strip_mode js' instead",
+            });
+            strip.js = true;
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--with_base", opt)) {
+            withbase = true;
+            continue;
+        }
+
+        if (std.mem.eql(u8, "--strip_mode", opt)) {
+            const str = args.next() orelse {
+                log.fatal(.app, "missing argument value", .{ .arg = "--strip_mode" });
+                return error.InvalidArgument;
+            };
+
+            var it = std.mem.splitScalar(u8, str, ',');
+            while (it.next()) |part| {
+                const trimmed = std.mem.trim(u8, part, &std.ascii.whitespace);
+                if (std.mem.eql(u8, trimmed, "js")) {
+                    strip.js = true;
+                } else if (std.mem.eql(u8, trimmed, "ui")) {
+                    strip.ui = true;
+                } else if (std.mem.eql(u8, trimmed, "css")) {
+                    strip.css = true;
+                } else if (std.mem.eql(u8, trimmed, "full")) {
+                    strip.js = true;
+                    strip.ui = true;
+                    strip.css = true;
+                } else {
+                    log.fatal(.app, "invalid option choice", .{ .arg = "--strip_mode", .value = trimmed });
+                }
+            }
+            continue;
+        }
+
+        if (try parseCommonArg(allocator, opt, args, &common)) {
+            continue;
+        }
+
+        if (std.mem.startsWith(u8, opt, "--")) {
+            log.fatal(.app, "unknown argument", .{ .mode = "fetch", .arg = opt });
+            return error.UnkownOption;
+        }
+
+        if (url != null) {
+            log.fatal(.app, "duplicate fetch url", .{ .help = "only 1 URL can be specified" });
+            return error.TooManyURLs;
+        }
+        url = try allocator.dupeZ(u8, opt);
+    }
+
+    if (url == null) {
+        log.fatal(.app, "missing fetch url", .{ .help = "URL to fetch must be provided" });
+        return error.MissingURL;
+    }
+
+    return .{
+        .url = url.?,
+        .dump_mode = dump_mode,
+        .strip = strip,
+        .common = common,
+        .withbase = withbase,
+    };
+}
+
+fn parseCommonArg(
+    allocator: Allocator,
+    opt: []const u8,
+    args: *std.process.ArgIterator,
+    common: *Common,
+) !bool {
+    if (std.mem.eql(u8, "--insecure_disable_tls_host_verification", opt)) {
+        common.tls_verify_host = false;
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--obey_robots", opt)) {
+        common.obey_robots = true;
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_proxy", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_proxy" });
+            return error.InvalidArgument;
+        };
+        common.http_proxy = try allocator.dupeZ(u8, str);
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--proxy_bearer_token", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--proxy_bearer_token" });
+            return error.InvalidArgument;
+        };
+        common.proxy_bearer_token = try allocator.dupeZ(u8, str);
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_max_concurrent", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_max_concurrent" });
+            return error.InvalidArgument;
+        };
+
+        common.http_max_concurrent = std.fmt.parseInt(u8, str, 10) catch |err| {
+            log.fatal(.app, "invalid argument value", .{ .arg = "--http_max_concurrent", .err = err });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_max_host_open", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_max_host_open" });
+            return error.InvalidArgument;
+        };
+
+        common.http_max_host_open = std.fmt.parseInt(u8, str, 10) catch |err| {
+            log.fatal(.app, "invalid argument value", .{ .arg = "--http_max_host_open", .err = err });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_connect_timeout", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_connect_timeout" });
+            return error.InvalidArgument;
+        };
+
+        common.http_connect_timeout = std.fmt.parseInt(u31, str, 10) catch |err| {
+            log.fatal(.app, "invalid argument value", .{ .arg = "--http_connect_timeout", .err = err });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_timeout", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_timeout" });
+            return error.InvalidArgument;
+        };
+
+        common.http_timeout = std.fmt.parseInt(u31, str, 10) catch |err| {
+            log.fatal(.app, "invalid argument value", .{ .arg = "--http_timeout", .err = err });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--http_max_response_size", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--http_max_response_size" });
+            return error.InvalidArgument;
+        };
+
+        common.http_max_response_size = std.fmt.parseInt(usize, str, 10) catch |err| {
+            log.fatal(.app, "invalid argument value", .{ .arg = "--http_max_response_size", .err = err });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--log_level", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--log_level" });
+            return error.InvalidArgument;
+        };
+
+        common.log_level = std.meta.stringToEnum(log.Level, str) orelse blk: {
+            if (std.mem.eql(u8, str, "error")) {
+                break :blk .err;
+            }
+            log.fatal(.app, "invalid option choice", .{ .arg = "--log_level", .value = str });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--log_format", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--log_format" });
+            return error.InvalidArgument;
+        };
+
+        common.log_format = std.meta.stringToEnum(log.Format, str) orelse {
+            log.fatal(.app, "invalid option choice", .{ .arg = "--log_format", .value = str });
+            return error.InvalidArgument;
+        };
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--log_filter_scopes", opt)) {
+        if (builtin.mode != .Debug) {
+            log.fatal(.app, "experimental", .{ .help = "log scope filtering is only available in debug builds" });
+            return false;
+        }
+
+        const str = args.next() orelse {
+            // disables the default filters
+            common.log_filter_scopes = &.{};
+            return true;
+        };
+
+        var arr: std.ArrayList(log.Scope) = .empty;
+
+        var it = std.mem.splitScalar(u8, str, ',');
+        while (it.next()) |part| {
+            try arr.append(allocator, std.meta.stringToEnum(log.Scope, part) orelse {
+                log.fatal(.app, "invalid option choice", .{ .arg = "--log_filter_scopes", .value = part });
+                return false;
+            });
+        }
+        common.log_filter_scopes = arr.items;
+        return true;
+    }
+
+    if (std.mem.eql(u8, "--user_agent_suffix", opt)) {
+        const str = args.next() orelse {
+            log.fatal(.app, "missing argument value", .{ .arg = "--user_agent_suffix" });
+            return error.InvalidArgument;
+        };
+        for (str) |c| {
+            if (!std.ascii.isPrint(c)) {
+                log.fatal(.app, "not printable character", .{ .arg = "--user_agent_suffix" });
+                return error.InvalidArgument;
+            }
+        }
+        common.user_agent_suffix = try allocator.dupe(u8, str);
+        return true;
+    }
+
+    return false;
+}

src/Notification.zig

@@ -39,10 +39,9 @@ const List = std.DoublyLinkedList;
 // CDP code registers for the "network_bytes_sent" event, because it needs to
 // send messages to the client when this happens. Our HTTP client could then
 // emit a "network_bytes_sent" message. It would be easy, and it would work.
-// That is, it would work until the Telemetry code makes an HTTP request, and
-// because everything's just one big global, that gets picked up by the
-// registered CDP listener, and the telemetry network activity gets sent to the
-// CDP client.
+// That is, it would work until multiple CDP clients connect, and because
+// everything's just one big global, events from one CDP session would be sent
+// to all CDP clients.
 //
 // To avoid this, one way or another, we need scoping. We could still have
 // a global registry but every "register" and every "emit" has some type of
@@ -50,14 +49,10 @@ const List = std.DoublyLinkedList;
 // between components to share a common scope.
 //
 // Instead, the approach that we take is to have a notification instance per
-// scope. This makes some things harder, but we only plan on having 2
-// notification instances  at a given time: one in a Browser and one in the App.
-// What about something like Telemetry, which lives outside of a Browser but
-// still cares about Browser-events (like .page_navigate)? When the Browser
-// notification is created, a `notification_created` event is raised in the
-// App's notification, which Telemetry is registered for. This allows Telemetry
-// to register for events in the Browser notification. See the Telemetry's
-// register function.
+// CDP connection (BrowserContext). Each CDP connection has its own notification
+// that is shared across all Sessions (tabs) within that connection. This ensures
+// proper isolation between different CDP clients while allowing a single client
+// to receive events from all its tabs.
 const Notification = @This();
 // Every event type (which are hard-coded), has a list of Listeners.
 // When the event happens, we dispatch to those listener.
@@ -66,7 +61,7 @@ event_listeners: EventListeners,
 // list of listeners for a specified receiver
 // @intFromPtr(receiver) -> [listener1, listener2, ...]
 // Used when `unregisterAll` is called.
-listeners: std.AutoHashMapUnmanaged(usize, std.ArrayListUnmanaged(*Listener)),
+listeners: std.AutoHashMapUnmanaged(usize, std.ArrayList(*Listener)),
 
 allocator: Allocator,
 mem_pool: std.heap.MemoryPool(Listener),
@@ -85,7 +80,6 @@ const EventListeners = struct {
     http_request_auth_required: List = .{},
     http_response_data: List = .{},
     http_response_header_done: List = .{},
-    notification_created: List = .{},
 };
 
 const Events = union(enum) {
@@ -102,7 +96,6 @@ const Events = union(enum) {
     http_request_done: *const RequestDone,
     http_response_data: *const ResponseData,
     http_response_header_done: *const ResponseHeaderDone,
-    notification_created: *Notification,
 };
 const EventType = std.meta.FieldEnum(Events);
 
@@ -162,12 +155,7 @@ pub const RequestFail = struct {
     err: anyerror,
 };
 
-pub fn init(allocator: Allocator, parent: ?*Notification) !*Notification {
-
-    // This is put on the heap because we want to raise a .notification_created
-    // event, so that, something like Telemetry, can receive the
-    // .page_navigate event on all notification instances. That can only work
-    // if we dispatch .notification_created with a *Notification.
+pub fn init(allocator: Allocator) !*Notification {
     const notification = try allocator.create(Notification);
     errdefer allocator.destroy(notification);
 
@@ -178,10 +166,6 @@ pub fn init(allocator: Allocator, parent: ?*Notification) !*Notification {
         .mem_pool = std.heap.MemoryPool(Listener).init(allocator),
     };
 
-    if (parent) |pn| {
-        pn.dispatch(.notification_created, notification);
-    }
-
     return notification;
 }
 
@@ -256,6 +240,9 @@ pub fn unregisterAll(self: *Notification, receiver: *anyopaque) void {
 }
 
 pub fn dispatch(self: *Notification, comptime event: EventType, data: ArgType(event)) void {
+    if (self.listeners.count() == 0) {
+        return;
+    }
     const list = &@field(self.event_listeners, @tagName(event));
 
     var node = list.first;
@@ -313,7 +300,7 @@ const Listener = struct {
 
 const testing = std.testing;
 test "Notification" {
-    var notifier = try Notification.init(testing.allocator, null);
+    var notifier = try Notification.init(testing.allocator);
     defer notifier.deinit();
 
     // noop

src/Server.zig

@@ -28,23 +28,25 @@ const ArenaAllocator = std.heap.ArenaAllocator;
 
 const log = @import("log.zig");
 const App = @import("App.zig");
+const Config = @import("Config.zig");
 const CDP = @import("cdp/cdp.zig").CDP;
-
-const MAX_HTTP_REQUEST_SIZE = 4096;
-
-// max message size
-// +14 for max websocket payload overhead
-// +140 for the max control packet that might be interleaved in a message
-const MAX_MESSAGE_SIZE = 512 * 1024 + 14 + 140;
+const Http = @import("http/Http.zig");
+const HttpClient = @import("http/Client.zig");
 
 const Server = @This();
+
 app: *App,
-shutdown: bool = false,
+shutdown: std.atomic.Value(bool) = .init(false),
 allocator: Allocator,
-client: ?posix.socket_t,
 listener: ?posix.socket_t,
 json_version_response: []const u8,
 
+// Thread management
+active_threads: std.atomic.Value(u32) = .init(0),
+clients: std.ArrayList(*Client) = .{},
+client_mutex: std.Thread.Mutex = .{},
+clients_pool: std.heap.MemoryPool(Client),
+
 pub fn init(app: *App, address: net.Address) !Server {
     const allocator = app.allocator;
     const json_version_response = try buildJSONVersionResponse(allocator, address);
@@ -52,19 +54,28 @@ pub fn init(app: *App, address: net.Address) !Server {
 
     return .{
         .app = app,
-        .client = null,
         .listener = null,
         .allocator = allocator,
         .json_version_response = json_version_response,
+        .clients_pool = std.heap.MemoryPool(Client).init(app.allocator),
     };
 }
 
 /// Interrupts the server so that main can complete normally and call all defer handlers.
 pub fn stop(self: *Server) void {
-    if (@atomicRmw(bool, &self.shutdown, .Xchg, true, .monotonic)) {
+    if (self.shutdown.swap(true, .release)) {
         return;
     }
 
+    // Shutdown all active clients
+    {
+        self.client_mutex.lock();
+        defer self.client_mutex.unlock();
+        for (self.clients.items) |client| {
+            client.stop();
+        }
+    }
+
     // Linux and BSD/macOS handle canceling a socket blocked on accept differently.
     // For Linux, we use std.shutdown, which will cause accept to return error.SocketNotListening (EINVAL).
     // For BSD, shutdown will return an error. Instead we call posix.close, which will result with error.ConnectionAborted (BADF).
@@ -81,17 +92,22 @@ pub fn stop(self: *Server) void {
 }
 
 pub fn deinit(self: *Server) void {
+    if (!self.shutdown.load(.acquire)) {
+        self.stop();
+    }
+
+    self.joinThreads();
     if (self.listener) |listener| {
         posix.close(listener);
         self.listener = null;
     }
-    // *if* server.run is running, we should really wait for it to return
-    // before existing from here.
+    self.clients.deinit(self.allocator);
+    self.clients_pool.deinit();
     self.allocator.free(self.json_version_response);
 }
 
 pub fn run(self: *Server, address: net.Address, timeout_ms: u32) !void {
-    const flags = posix.SOCK.STREAM | posix.SOCK.CLOEXEC;
+    const flags = posix.SOCK.STREAM | posix.SOCK.CLOEXEC | posix.SOCK.NONBLOCK;
     const listener = try posix.socket(address.any.family, flags, posix.IPPROTO.TCP);
     self.listener = listener;
 
@@ -101,16 +117,20 @@ pub fn run(self: *Server, address: net.Address, timeout_ms: u32) !void {
     }
 
     try posix.bind(listener, &address.any, address.getOsSockLen());
-    try posix.listen(listener, 1);
+    try posix.listen(listener, self.app.config.maxPendingConnections());
 
     log.info(.app, "server running", .{ .address = address });
-    while (!@atomicLoad(bool, &self.shutdown, .monotonic)) {
+    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);
@@ -119,97 +139,121 @@ pub fn run(self: *Server, address: net.Address, timeout_ms: u32) !void {
             }
         };
 
-        self.client = socket;
-        defer if (self.client) |s| {
-            posix.close(s);
-            self.client = null;
-        };
-
-        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);
-            log.info(.app, "client connected", .{ .ip = client_address });
-        }
-
-        self.readLoop(socket, timeout_ms) catch |err| {
-            log.err(.app, "CDP client loop", .{ .err = err });
+        self.spawnWorker(socket, timeout_ms) catch |err| {
+            log.err(.app, "CDP spawn", .{ .err = err });
+            posix.close(socket);
         };
     }
 }
 
-fn readLoop(self: *Server, socket: posix.socket_t, timeout_ms: u32) !void {
-    // This shouldn't be necessary, but the Client is HUGE (> 512KB) because
-    // it has a large read buffer. I don't know why, but v8 crashes if this
-    // is on the stack (and I assume it's related to its size).
-    const client = try self.allocator.create(Client);
-    defer self.allocator.destroy(client);
+fn handleConnection(self: *Server, socket: posix.socket_t, timeout_ms: u32) void {
+    defer posix.close(socket);
 
-    client.* = try Client.init(socket, self);
+    // Client is HUGE (> 512KB) because it has a large read buffer.
+    // V8 crashes if this is on the stack (likely related to its size).
+    const client = self.getClient() catch |err| {
+        log.err(.app, "CDP client create", .{ .err = err });
+        return;
+    };
+    defer self.releaseClient(client);
+
+    client.* = Client.init(
+        socket,
+        self.allocator,
+        self.app,
+        self.json_version_response,
+        timeout_ms,
+    ) catch |err| {
+        log.err(.app, "CDP client init", .{ .err = err });
+        return;
+    };
     defer client.deinit();
 
-    var http = &self.app.http;
-    http.addCDPClient(.{
-        .socket = socket,
-        .ctx = client,
-        .blocking_read_start = Client.blockingReadStart,
-        .blocking_read = Client.blockingRead,
-        .blocking_read_end = Client.blockingReadStop,
-    });
-    defer http.removeCDPClient();
+    self.registerClient(client);
+    defer self.unregisterClient(client);
 
-    lp.assert(client.mode == .http, "Server.readLoop invalid mode", .{});
-    while (true) {
-        if (http.poll(timeout_ms) != .cdp_socket) {
-            log.info(.app, "CDP timeout", .{});
-            return;
-        }
-
-        if (client.readSocket() == false) {
-            return;
-        }
-
-        if (client.mode == .cdp) {
-            break; // switch to our CDP loop
-        }
+    // Check shutdown after registering to avoid missing stop() signal.
+    // If stop() already iterated over clients, this client won't receive stop()
+    // and would block joinThreads() indefinitely.
+    if (self.shutdown.load(.acquire)) {
+        return;
     }
 
-    var cdp = &client.mode.cdp;
-    var last_message = timestamp(.monotonic);
-    var ms_remaining = timeout_ms;
-    while (true) {
-        switch (cdp.pageWait(ms_remaining)) {
-            .cdp_socket => {
-                if (client.readSocket() == false) {
-                    return;
-                }
-                last_message = timestamp(.monotonic);
-                ms_remaining = timeout_ms;
-            },
-            .no_page => {
-                if (http.poll(ms_remaining) != .cdp_socket) {
-                    log.info(.app, "CDP timeout", .{});
-                    return;
-                }
-                if (client.readSocket() == false) {
-                    return;
-                }
-                last_message = timestamp(.monotonic);
-                ms_remaining = timeout_ms;
-            },
-            .done => {
-                const elapsed = timestamp(.monotonic) - last_message;
-                if (elapsed > ms_remaining) {
-                    log.info(.app, "CDP timeout", .{});
-                    return;
-                }
-                ms_remaining -= @intCast(elapsed);
-            },
-            .navigate => unreachable, // must have been handled by the session
+    client.start();
+}
+
+fn getClient(self: *Server) !*Client {
+    self.client_mutex.lock();
+    defer self.client_mutex.unlock();
+    return self.clients_pool.create();
+}
+
+fn releaseClient(self: *Server, client: *Client) void {
+    self.client_mutex.lock();
+    defer self.client_mutex.unlock();
+    self.clients_pool.destroy(client);
+}
+
+fn registerClient(self: *Server, client: *Client) void {
+    self.client_mutex.lock();
+    defer self.client_mutex.unlock();
+    self.clients.append(self.allocator, client) catch {};
+}
+
+fn unregisterClient(self: *Server, client: *Client) void {
+    self.client_mutex.lock();
+    defer self.client_mutex.unlock();
+    for (self.clients.items, 0..) |c, i| {
+        if (c == client) {
+            _ = self.clients.swapRemove(i);
+            break;
         }
     }
 }
 
+fn spawnWorker(self: *Server, socket: posix.socket_t, timeout_ms: u32) !void {
+    if (self.shutdown.load(.acquire)) {
+        return error.ShuttingDown;
+    }
+
+    // Atomically increment active_threads only if below max_connections.
+    // Uses CAS loop to avoid race between checking the limit and incrementing.
+    //
+    // cmpxchgWeak may fail for two reasons:
+    // 1. Another thread changed the value (increment or decrement)
+    // 2. Spurious failure on some architectures (e.g. ARM)
+    //
+    // We use Weak instead of Strong because we need a retry loop anyway:
+    // if CAS fails because a thread finished (counter decreased), we should
+    // retry rather than return an error - there may now be room for a new connection.
+    //
+    // On failure, cmpxchgWeak returns the actual value, which we reuse to avoid
+    // an extra load on the next iteration.
+    const max_connections = self.app.config.maxConnections();
+    var current = self.active_threads.load(.monotonic);
+    while (current < max_connections) {
+        current = self.active_threads.cmpxchgWeak(current, current + 1, .monotonic, .monotonic) orelse break;
+    } else {
+        return error.MaxThreadsReached;
+    }
+    errdefer _ = self.active_threads.fetchSub(1, .monotonic);
+
+    const thread = try std.Thread.spawn(.{}, runWorker, .{ self, socket, timeout_ms });
+    thread.detach();
+}
+
+fn runWorker(self: *Server, socket: posix.socket_t, timeout_ms: u32) void {
+    defer _ = self.active_threads.fetchSub(1, .monotonic);
+    handleConnection(self, socket, timeout_ms);
+}
+
+fn joinThreads(self: *Server) void {
+    while (self.active_threads.load(.monotonic) > 0) {
+        std.Thread.sleep(10 * std.time.ns_per_ms);
+    }
+}
+
+// Handle exactly one TCP connection.
 pub const Client = struct {
     // The client is initially serving HTTP requests but, under normal circumstances
     // should eventually be upgraded to a websocket connections
@@ -218,11 +262,15 @@ pub const Client = struct {
         cdp: CDP,
     },
 
-    server: *Server,
+    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 };
 
@@ -233,25 +281,49 @@ pub const Client = struct {
     // "private-use" close codes must be from 4000-49999
     const CLOSE_TIMEOUT = [_]u8{ 136, 2, 15, 160 }; // code: 4000
 
-    fn init(socket: posix.socket_t, server: *Server) !Client {
+    fn init(
+        socket: posix.socket_t,
+        allocator: Allocator,
+        app: *App,
+        json_version_response: []const u8,
+        timeout_ms: u32,
+    ) !Client {
+        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);
+            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(server.allocator);
+        var reader = try Reader(true).init(allocator);
         errdefer reader.deinit();
 
+        const http = try app.http.createClient(allocator);
+        errdefer http.deinit();
+
         return .{
             .socket = socket,
-            .server = server,
+            .allocator = allocator,
+            .app = app,
+            .http = http,
+            .json_version_response = json_version_response,
             .reader = reader,
             .mode = .{ .http = {} },
             .socket_flags = socket_flags,
-            .send_arena = ArenaAllocator.init(server.allocator),
+            .send_arena = ArenaAllocator.init(allocator),
+            .timeout_ms = timeout_ms,
         };
     }
 
+    fn stop(self: *Client) void {
+        posix.shutdown(self.socket, .recv) catch {};
+    }
+
     fn deinit(self: *Client) void {
         switch (self.mode) {
             .cdp => |*cdp| cdp.deinit(),
@@ -259,6 +331,88 @@ pub const Client = struct {
         }
         self.reader.deinit();
         self.send_arena.deinit();
+        self.http.deinit();
+    }
+
+    fn start(self: *Client) void {
+        const http = self.http;
+        http.cdp_client = .{
+            .socket = self.socket,
+            .ctx = self,
+            .blocking_read_start = Client.blockingReadStart,
+            .blocking_read = Client.blockingRead,
+            .blocking_read_end = Client.blockingReadStop,
+        };
+        defer http.cdp_client = null;
+
+        self.httpLoop(http) catch |err| {
+            log.err(.app, "CDP client loop", .{ .err = err });
+        };
+    }
+
+    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| {
+                log.err(.app, "http tick", .{ .err = err });
+                return;
+            };
+            if (status != .cdp_socket) {
+                log.info(.app, "CDP timeout", .{});
+                return;
+            }
+
+            if (self.readSocket() == false) {
+                return;
+            }
+
+            if (self.mode == .cdp) {
+                break;
+            }
+        }
+
+        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;
+
+        while (true) {
+            switch (cdp.pageWait(ms_remaining)) {
+                .cdp_socket => {
+                    if (self.readSocket() == false) {
+                        return;
+                    }
+                    last_message = timestamp(.monotonic);
+                    ms_remaining = self.timeout_ms;
+                },
+                .no_page => {
+                    const status = http.tick(ms_remaining) catch |err| {
+                        log.err(.app, "http tick", .{ .err = err });
+                        return;
+                    };
+                    if (status != .cdp_socket) {
+                        log.info(.app, "CDP timeout", .{});
+                        return;
+                    }
+                    if (self.readSocket() == false) {
+                        return;
+                    }
+                    last_message = timestamp(.monotonic);
+                    ms_remaining = self.timeout_ms;
+                },
+                .done => {
+                    const elapsed = timestamp(.monotonic) - last_message;
+                    if (elapsed > ms_remaining) {
+                        log.info(.app, "CDP timeout", .{});
+                        return;
+                    }
+                    ms_remaining -= @intCast(elapsed);
+                },
+            }
+        }
     }
 
     fn blockingReadStart(ctx: *anyopaque) bool {
@@ -315,7 +469,7 @@ pub const Client = struct {
         lp.assert(self.reader.pos == 0, "Client.HTTP pos", .{ .pos = self.reader.pos });
         const request = self.reader.buf[0..self.reader.len];
 
-        if (request.len > MAX_HTTP_REQUEST_SIZE) {
+        if (request.len > Config.CDP_MAX_HTTP_REQUEST_SIZE) {
             self.writeHTTPErrorResponse(413, "Request too large");
             return error.RequestTooLarge;
         }
@@ -368,7 +522,7 @@ pub const Client = struct {
         }
 
         if (std.mem.eql(u8, url, "/json/version")) {
-            try self.send(self.server.json_version_response);
+            try self.send(self.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
@@ -473,7 +627,7 @@ pub const Client = struct {
             break :blk res;
         };
 
-        self.mode = .{ .cdp = try CDP.init(self.server.app, self) };
+        self.mode = .{ .cdp = try CDP.init(self.app, self.http, self) };
         return self.send(response);
     }
 
@@ -561,7 +715,7 @@ pub const Client = struct {
 
     pub fn sendJSONRaw(
         self: *Client,
-        buf: std.ArrayListUnmanaged(u8),
+        buf: std.ArrayList(u8),
     ) !void {
         // Dangerous API!. We assume the caller has reserved the first 10
         // bytes in `buf`.
@@ -708,7 +862,7 @@ fn Reader(comptime EXPECT_MASK: bool) type {
                     if (message_len > 125) {
                         return error.ControlTooLarge;
                     }
-                } else if (message_len > MAX_MESSAGE_SIZE) {
+                } else if (message_len > Config.CDP_MAX_MESSAGE_SIZE) {
                     return error.TooLarge;
                 } else if (message_len > self.buf.len) {
                     const len = self.buf.len;
@@ -736,7 +890,7 @@ fn Reader(comptime EXPECT_MASK: bool) type {
 
                 if (is_continuation) {
                     const fragments = &(self.fragments orelse return error.InvalidContinuation);
-                    if (fragments.message.items.len + message_len > MAX_MESSAGE_SIZE) {
+                    if (fragments.message.items.len + message_len > Config.CDP_MAX_MESSAGE_SIZE) {
                         return error.TooLarge;
                     }
 
@@ -883,7 +1037,7 @@ fn growBuffer(allocator: Allocator, buf: []u8, required_capacity: usize) ![]u8 {
 
 const Fragments = struct {
     type: Message.Type,
-    message: std.ArrayListUnmanaged(u8),
+    message: std.ArrayList(u8),
 };
 
 const Message = struct {
@@ -907,7 +1061,7 @@ const OpCode = enum(u8) {
     pong = 128 | 10,
 };
 
-fn fillWebsocketHeader(buf: std.ArrayListUnmanaged(u8)) []const u8 {
+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:
@@ -1342,7 +1496,7 @@ fn assertWebSocketMessage(expected: []const u8, input: []const u8) !void {
 }
 
 const MockCDP = struct {
-    messages: std.ArrayListUnmanaged([]const u8) = .{},
+    messages: std.ArrayList([]const u8) = .{},
 
     allocator: Allocator = testing.allocator,
 

src/TestHTTPServer.zig

@@ -20,7 +20,7 @@ const std = @import("std");
 
 const TestHTTPServer = @This();
 
-shutdown: bool,
+shutdown: std.atomic.Value(bool),
 listener: ?std.net.Server,
 handler: Handler,
 
@@ -28,16 +28,23 @@ const Handler = *const fn (req: *std.http.Server.Request) anyerror!void;
 
 pub fn init(handler: Handler) TestHTTPServer {
     return .{
-        .shutdown = true,
+        .shutdown = .init(true),
         .listener = null,
         .handler = handler,
     };
 }
 
 pub fn deinit(self: *TestHTTPServer) void {
-    self.shutdown = true;
+    self.listener = null;
+}
+
+pub fn stop(self: *TestHTTPServer) void {
+    self.shutdown.store(true, .release);
     if (self.listener) |*listener| {
-        listener.deinit();
+        switch (@import("builtin").target.os.tag) {
+            .linux => std.posix.shutdown(listener.stream.handle, .recv) catch {},
+            else => std.posix.close(listener.stream.handle),
+        }
     }
 }
 
@@ -46,12 +53,13 @@ pub fn run(self: *TestHTTPServer, wg: *std.Thread.WaitGroup) !void {
 
     self.listener = try address.listen(.{ .reuse_address = true });
     var listener = &self.listener.?;
+    self.shutdown.store(false, .release);
 
     wg.finish();
 
     while (true) {
         const conn = listener.accept() catch |err| {
-            if (self.shutdown) {
+            if (self.shutdown.load(.acquire) or err == error.SocketNotListening) {
                 return;
             }
             return err;

src/browser/Browser.zig

@@ -24,14 +24,14 @@ const ArenaAllocator = std.heap.ArenaAllocator;
 const js = @import("js/js.zig");
 const log = @import("../log.zig");
 const App = @import("../App.zig");
+const HttpClient = @import("../http/Client.zig");
 
 const ArenaPool = App.ArenaPool;
-const HttpClient = App.Http.Client;
-const Notification = App.Notification;
 
 const IS_DEBUG = @import("builtin").mode == .Debug;
 
 const Session = @import("Session.zig");
+const Notification = @import("../Notification.zig");
 
 // Browser is an instance of the browser.
 // You can create multiple browser instances.
@@ -44,54 +44,38 @@ session: ?Session,
 allocator: Allocator,
 arena_pool: *ArenaPool,
 http_client: *HttpClient,
-call_arena: ArenaAllocator,
-page_arena: ArenaAllocator,
-session_arena: ArenaAllocator,
-transfer_arena: ArenaAllocator,
-notification: *Notification,
 
-pub fn init(app: *App) !Browser {
+const InitOpts = struct {
+    env: js.Env.InitOpts = .{},
+    http_client: *HttpClient,
+};
+
+pub fn init(app: *App, opts: InitOpts) !Browser {
     const allocator = app.allocator;
 
-    var env = try js.Env.init(allocator, &app.platform, &app.snapshot);
+    var env = try js.Env.init(app, opts.env);
     errdefer env.deinit();
 
-    const notification = try Notification.init(allocator, app.notification);
-    app.http.client.notification = notification;
-    app.http.client.next_request_id = 0; // Should we track ids in CDP only?
-    errdefer notification.deinit();
-
     return .{
         .app = app,
         .env = env,
         .session = null,
         .allocator = allocator,
-        .notification = notification,
         .arena_pool = &app.arena_pool,
-        .http_client = app.http.client,
-        .call_arena = ArenaAllocator.init(allocator),
-        .page_arena = ArenaAllocator.init(allocator),
-        .session_arena = ArenaAllocator.init(allocator),
-        .transfer_arena = ArenaAllocator.init(allocator),
+        .http_client = opts.http_client,
     };
 }
 
 pub fn deinit(self: *Browser) void {
     self.closeSession();
     self.env.deinit();
-    self.call_arena.deinit();
-    self.page_arena.deinit();
-    self.session_arena.deinit();
-    self.transfer_arena.deinit();
-    self.http_client.notification = null;
-    self.notification.deinit();
 }
 
-pub fn newSession(self: *Browser) !*Session {
+pub fn newSession(self: *Browser, notification: *Notification) !*Session {
     self.closeSession();
     self.session = @as(Session, undefined);
     const session = &self.session.?;
-    try Session.init(session, self);
+    try Session.init(session, self, notification);
     return session;
 }
 
@@ -99,7 +83,6 @@ pub fn closeSession(self: *Browser) void {
     if (self.session) |*session| {
         session.deinit();
         self.session = null;
-        _ = self.session_arena.reset(.{ .retain_with_limit = 1 * 1024 * 1024 });
         self.env.memoryPressureNotification(.critical);
     }
 }
@@ -108,6 +91,10 @@ pub fn runMicrotasks(self: *const Browser) void {
     self.env.runMicrotasks();
 }
 
+pub fn runMacrotasks(self: *Browser) !?u64 {
+    return try self.env.runMacrotasks();
+}
+
 pub fn runMessageLoop(self: *const Browser) void {
     while (self.env.pumpMessageLoop()) {
         if (comptime IS_DEBUG) {

src/browser/EventManager.zig

@@ -28,28 +28,52 @@ const Page = @import("Page.zig");
 const Node = @import("webapi/Node.zig");
 const Event = @import("webapi/Event.zig");
 const EventTarget = @import("webapi/EventTarget.zig");
+const Element = @import("webapi/Element.zig");
 
 const Allocator = std.mem.Allocator;
 
 const IS_DEBUG = builtin.mode == .Debug;
 
+const EventKey = struct {
+    event_target: usize,
+    type_string: String,
+};
+
+const EventKeyContext = struct {
+    pub fn hash(_: @This(), key: EventKey) u64 {
+        var hasher = std.hash.Wyhash.init(0);
+        hasher.update(std.mem.asBytes(&key.event_target));
+        hasher.update(key.type_string.str());
+        return hasher.final();
+    }
+
+    pub fn eql(_: @This(), a: EventKey, b: EventKey) bool {
+        return a.event_target == b.event_target and a.type_string.eql(b.type_string);
+    }
+};
+
 pub const EventManager = @This();
 
 page: *Page,
 arena: Allocator,
 listener_pool: std.heap.MemoryPool(Listener),
 list_pool: std.heap.MemoryPool(std.DoublyLinkedList),
-lookup: std.AutoHashMapUnmanaged(usize, *std.DoublyLinkedList),
+lookup: std.HashMapUnmanaged(
+    EventKey,
+    *std.DoublyLinkedList,
+    EventKeyContext,
+    std.hash_map.default_max_load_percentage,
+),
 dispatch_depth: usize,
 deferred_removals: std.ArrayList(struct { list: *std.DoublyLinkedList, listener: *Listener }),
 
-pub fn init(page: *Page) EventManager {
+pub fn init(arena: Allocator, page: *Page) EventManager {
     return .{
         .page = page,
         .lookup = .{},
-        .arena = page.arena,
-        .list_pool = std.heap.MemoryPool(std.DoublyLinkedList).init(page.arena),
-        .listener_pool = std.heap.MemoryPool(Listener).init(page.arena),
+        .arena = arena,
+        .list_pool = .init(arena),
+        .listener_pool = .init(arena),
         .dispatch_depth = 0,
         .deferred_removals = .{},
     };
@@ -69,7 +93,7 @@ pub const Callback = union(enum) {
 
 pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, callback: Callback, opts: RegisterOptions) !void {
     if (comptime IS_DEBUG) {
-        log.debug(.event, "eventManager.register", .{ .type = typ, .capture = opts.capture, .once = opts.once, .target = target });
+        log.debug(.event, "eventManager.register", .{ .type = typ, .capture = opts.capture, .once = opts.once, .target = target.toString() });
     }
 
     // If a signal is provided and already aborted, don't register the listener
@@ -79,20 +103,24 @@ pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, call
         }
     }
 
-    const gop = try self.lookup.getOrPut(self.arena, @intFromPtr(target));
+    // Allocate the type string we'll use in both listener and key
+    const type_string = try String.init(self.arena, typ, .{});
+
+    const gop = try self.lookup.getOrPut(self.arena, .{
+        .type_string = type_string,
+        .event_target = @intFromPtr(target),
+    });
     if (gop.found_existing) {
         // check for duplicate callbacks already registered
         var node = gop.value_ptr.*.first;
         while (node) |n| {
             const listener: *Listener = @alignCast(@fieldParentPtr("node", n));
-            if (listener.typ.eqlSlice(typ)) {
-                const is_duplicate = switch (callback) {
-                    .object => |obj| listener.function.eqlObject(obj),
-                    .function => |func| listener.function.eqlFunction(func),
-                };
-                if (is_duplicate and listener.capture == opts.capture) {
-                    return;
-                }
+            const is_duplicate = switch (callback) {
+                .object => |obj| listener.function.eqlObject(obj),
+                .function => |func| listener.function.eqlFunction(func),
+            };
+            if (is_duplicate and listener.capture == opts.capture) {
+                return;
             }
             node = n.next;
         }
@@ -114,20 +142,34 @@ pub fn register(self: *EventManager, target: *EventTarget, typ: []const u8, call
         .passive = opts.passive,
         .function = func,
         .signal = opts.signal,
-        .typ = try String.init(self.arena, typ, .{}),
+        .typ = type_string,
     };
     // append the listener to the list of listeners for this target
     gop.value_ptr.*.append(&listener.node);
 }
 
 pub fn remove(self: *EventManager, target: *EventTarget, typ: []const u8, callback: Callback, use_capture: bool) void {
-    const list = self.lookup.get(@intFromPtr(target)) orelse return;
-    if (findListener(list, typ, callback, use_capture)) |listener| {
+    const list = self.lookup.get(.{
+        .type_string = .wrap(typ),
+        .event_target = @intFromPtr(target),
+    }) orelse return;
+    if (findListener(list, callback, use_capture)) |listener| {
         self.removeListener(list, listener);
     }
 }
 
-pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) !void {
+// 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.
+const DispatchError = error{
+    OutOfMemory,
+    StringTooLarge,
+    JSExecCallback,
+    CompilationError,
+    ExecutionError,
+    JsException,
+};
+pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) DispatchError!void {
     if (comptime IS_DEBUG) {
         log.debug(.event, "eventManager.dispatch", .{ .type = event._type_string.str(), .bubbles = event._bubbles });
     }
@@ -154,9 +196,13 @@ pub fn dispatch(self: *EventManager, target: *EventTarget, event: *Event) !void
         .navigation,
         .screen,
         .screen_orientation,
+        .visual_viewport,
         .generic,
         => {
-            const list = self.lookup.get(@intFromPtr(target)) orelse return;
+            const list = self.lookup.get(.{
+                .event_target = @intFromPtr(target),
+                .type_string = event._type_string,
+            }) orelse return;
             try self.dispatchAll(list, target, event, &was_handled);
         },
     }
@@ -199,27 +245,37 @@ pub fn dispatchWithFunction(self: *EventManager, target: *EventTarget, event: *E
         }
     }
 
-    const list = self.lookup.get(@intFromPtr(target)) orelse return;
+    const list = self.lookup.get(.{
+        .event_target = @intFromPtr(target),
+        .type_string = event._type_string,
+    }) orelse return;
     try self.dispatchAll(list, target, event, &was_dispatched);
 }
 
 fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled: *bool) !void {
     const ShadowRoot = @import("webapi/ShadowRoot.zig");
 
+    const page = self.page;
+    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;
+        // Handle checkbox/radio activation rollback or commit
+        if (activation_state) |state| {
+            state.restore(event, page);
+        }
 
         // Execute default action if not prevented
         if (event._prevent_default) {
             // can't return in a defer (╯°□°)╯︵ ┻━┻
-        } else if (event._type_string.eqlSlice("click")) {
-            self.page.handleClick(target) catch |err| {
+        } else if (event._type_string.eql(comptime .wrap("click"))) {
+            page.handleClick(target) catch |err| {
                 log.warn(.event, "page.click", .{ .err = err });
             };
-        } else if (event._type_string.eqlSlice("keydown")) {
-            self.page.handleKeydown(target, event) catch |err| {
+        } else if (event._type_string.eql(comptime .wrap("keydown"))) {
+            page.handleKeydown(target, event) catch |err| {
                 log.warn(.event, "page.keydown", .{ .err = err });
             };
         }
@@ -254,7 +310,7 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     // Even though the window isn't part of the DOM, events always propagate
     // through it in the capture phase (unless we stopped at a shadow boundary)
     if (path_len < path_buffer.len) {
-        path_buffer[path_len] = self.page.window.asEventTarget();
+        path_buffer[path_len] = page.window.asEventTarget();
         path_len += 1;
     }
 
@@ -267,7 +323,10 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     while (i > 1) {
         i -= 1;
         const current_target = path[i];
-        if (self.lookup.get(@intFromPtr(current_target))) |list| {
+        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;
@@ -278,10 +337,36 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     // Phase 2: At target
     event._event_phase = .at_target;
     const target_et = target.asEventTarget();
-    if (self.lookup.get(@intFromPtr(target_et))) |list| {
-        try self.dispatchPhase(list, target_et, event, was_handled, null);
-        if (event._stop_propagation) {
-            return;
+
+    blk: {
+        // Get inline handler (e.g., onclick property) for this target
+        if (self.getInlineHandler(target_et, event)) |inline_handler| {
+            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) {
+                return;
+            }
+
+            if (event._stop_immediate_propagation) {
+                break :blk;
+            }
+        }
+
+        if (self.lookup.get(.{
+            .type_string = event._type_string,
+            .event_target = @intFromPtr(target_et),
+        })) |list| {
+            try self.dispatchPhase(list, target_et, event, was_handled, null);
+            if (event._stop_propagation) {
+                return;
+            }
         }
     }
 
@@ -290,7 +375,10 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
     if (event._bubbles) {
         event._event_phase = .bubbling_phase;
         for (path[1..]) |current_target| {
-            if (self.lookup.get(@intFromPtr(current_target))) |list| {
+            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;
@@ -302,7 +390,6 @@ fn dispatchNode(self: *EventManager, target: *Node, event: *Event, was_handled:
 
 fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_target: *EventTarget, event: *Event, was_handled: *bool, comptime capture_only: ?bool) !void {
     const page = self.page;
-    const typ = event._type_string;
 
     // Track dispatch depth for deferred removal
     self.dispatch_depth += 1;
@@ -337,9 +424,6 @@ fn dispatchPhase(self: *EventManager, list: *std.DoublyLinkedList, current_targe
         node = n.next;
 
         // Skip non-matching listeners
-        if (!listener.typ.eql(typ)) {
-            continue;
-        }
         if (comptime capture_only) |capture| {
             if (listener.capture != capture) {
                 continue;
@@ -407,6 +491,19 @@ fn dispatchAll(self: *EventManager, list: *std.DoublyLinkedList, current_target:
     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,
+        else => return null,
+    };
+
+    return self.page.getAttrListener(element, handler_type);
+}
+
 fn removeListener(self: *EventManager, list: *std.DoublyLinkedList, listener: *Listener) void {
     // If we're in a dispatch, defer removal to avoid invalidating iteration
     if (self.dispatch_depth > 0) {
@@ -419,7 +516,7 @@ fn removeListener(self: *EventManager, list: *std.DoublyLinkedList, listener: *L
     }
 }
 
-fn findListener(list: *const std.DoublyLinkedList, typ: []const u8, callback: Callback, capture: bool) ?*Listener {
+fn findListener(list: *const std.DoublyLinkedList, callback: Callback, capture: bool) ?*Listener {
     var node = list.first;
     while (node) |n| {
         node = n.next;
@@ -434,9 +531,6 @@ fn findListener(list: *const std.DoublyLinkedList, typ: []const u8, callback: Ca
         if (listener.capture != capture) {
             continue;
         }
-        if (!listener.typ.eqlSlice(typ)) {
-            continue;
-        }
         return listener;
     }
     return null;
@@ -525,3 +619,144 @@ fn isAncestorOrSelf(ancestor: *Node, node: *Node) bool {
 
     return false;
 }
+
+// Handles the default action for clicking on input checked/radio. Maybe this
+// could be generalized if needed, but I'm not sure. This wasn't obvious to me
+// but when an input is clicked, it's important to think about both the intent
+// and the actual result. Imagine you have an unchecked checkbox. When clicked,
+// the checkbox immediately becomes checked, and event handlers see this "checked"
+// intent. But a listener can preventDefault() in which case the check we did at
+// the start will be undone.
+// This is a bit more complicated for radio buttons, as the checking/unchecking
+// and the rollback can impact a different radio input. So if you "check" a radio
+// the intent is that it becomes checked and whatever was checked before becomes
+// unchecked, so that if you have to rollback (because of a preventDefault())
+// then both inputs have to revert to their original values.
+const ActivationState = struct {
+    old_checked: bool,
+    input: *Element.Html.Input,
+    previously_checked_radio: ?*Input,
+
+    const Input = Element.Html.Input;
+
+    fn create(event: *const Event, target: *Node, page: *Page) ?ActivationState {
+        if (event._type_string.eql(comptime .wrap("click")) == false) {
+            return null;
+        }
+
+        const input = target.is(Element.Html.Input) orelse return null;
+        if (input._input_type != .checkbox and input._input_type != .radio) {
+            return null;
+        }
+
+        const old_checked = input._checked;
+        var previously_checked_radio: ?*Element.Html.Input = null;
+
+        // For radio buttons, find the currently checked radio in the group
+        if (input._input_type == .radio and !old_checked) {
+            previously_checked_radio = try findCheckedRadioInGroup(input, page);
+        }
+
+        // Toggle checkbox or check radio (which unchecks others in group)
+        const new_checked = if (input._input_type == .checkbox) !old_checked else true;
+        try input.setChecked(new_checked, page);
+
+        return .{
+            .input = input,
+            .old_checked = old_checked,
+            .previously_checked_radio = previously_checked_radio,
+        };
+    }
+
+    fn restore(self: *const ActivationState, event: *const Event, page: *Page) void {
+        const input = self.input;
+        if (event._prevent_default) {
+            // Rollback: restore previous state
+            input._checked = self.old_checked;
+            input._checked_dirty = true;
+            if (self.previously_checked_radio) |prev_radio| {
+                prev_radio._checked = true;
+                prev_radio._checked_dirty = true;
+            }
+            return;
+        }
+
+        // Commit: fire input and change events only if state actually changed
+        // 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) {
+            fireEvent(page, input, "input") catch |err| {
+                log.warn(.event, "input event", .{ .err = err });
+            };
+            fireEvent(page, input, "change") catch |err| {
+                log.warn(.event, "change event", .{ .err = err });
+            };
+        }
+    }
+
+    fn findCheckedRadioInGroup(input: *Input, page: *Page) !?*Input {
+        const elem = input.asElement();
+
+        const name = elem.getAttributeSafe(comptime .wrap("name")) orelse return null;
+        if (name.len == 0) {
+            return null;
+        }
+
+        const form = input.getForm(page);
+
+        // Walk from the root of the tree containing this element
+        // This handles both document-attached and orphaned elements
+        const root = elem.asNode().getRootNode(null);
+
+        const TreeWalker = @import("webapi/TreeWalker.zig");
+        var walker = TreeWalker.Full.init(root, .{});
+
+        while (walker.next()) |node| {
+            const other_element = node.is(Element) orelse continue;
+            const other_input = other_element.is(Input) orelse continue;
+
+            if (other_input._input_type != .radio) {
+                continue;
+            }
+
+            // Skip the input we're checking from
+            if (other_input == input) {
+                continue;
+            }
+
+            const other_name = other_element.getAttributeSafe(comptime .wrap("name")) orelse continue;
+            if (!std.mem.eql(u8, name, other_name)) {
+                continue;
+            }
+
+            // Check if same form context
+            const other_form = other_input.getForm(page);
+            if (form) |f| {
+                const of = other_form orelse continue;
+                if (f != of) {
+                    continue; // Different forms
+                }
+            } else if (other_form != null) {
+                continue; // form is null but other has a form
+            }
+
+            if (other_input._checked) {
+                return other_input;
+            }
+        }
+
+        return null;
+    }
+
+    // Fire input or change event
+    fn fireEvent(page: *Page, input: *Input, comptime typ: []const u8) !void {
+        const event = try Event.initTrusted(comptime .wrap(typ), .{
+            .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

@@ -43,7 +43,9 @@ const IS_DEBUG = builtin.mode == .Debug;
 const assert = std.debug.assert;
 
 const Factory = @This();
+
 _page: *Page,
+_arena: Allocator,
 _slab: SlabAllocator,
 
 fn PrototypeChain(comptime types: []const type) type {
@@ -149,10 +151,11 @@ fn AutoPrototypeChain(comptime types: []const type) type {
     };
 }
 
-pub fn init(page: *Page) Factory {
+pub fn init(arena: Allocator, page: *Page) Factory {
     return .{
         ._page = page,
-        ._slab = SlabAllocator.init(page.arena, 128),
+        ._arena = arena,
+        ._slab = SlabAllocator.init(arena, 128),
     };
 }
 
@@ -172,60 +175,49 @@ pub fn eventTarget(self: *Factory, child: anytype) !*@TypeOf(child) {
     return chain.get(1);
 }
 
-fn eventInit(typ: []const u8, value: anytype, page: *Page) !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 .{
-        ._type = unionInit(Event.Type, value),
-        ._type_string = try String.init(page.arena, typ, .{}),
-        ._time_stamp = time_stamp,
-    };
+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, typ: []const u8, child: anytype) !*@TypeOf(child) {
-    const allocator = self._slab.allocator();
-
+pub fn event(self: *Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
     const chain = try PrototypeChain(
         &.{ Event, @TypeOf(child) },
-    ).allocate(allocator);
+    ).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(typ, chain.get(1), self._page);
+    event_ptr.* = try self.eventInit(arena, typ, chain.get(1));
     chain.setLeaf(1, child);
 
     return chain.get(1);
 }
 
-pub fn uiEvent(self: *Factory, typ: []const u8, child: anytype) !*@TypeOf(child) {
-    const allocator = self._slab.allocator();
-
+pub fn uiEvent(self: *Factory, arena: Allocator, typ: String, child: anytype) !*@TypeOf(child) {
     const chain = try PrototypeChain(
         &.{ Event, UIEvent, @TypeOf(child) },
-    ).allocate(allocator);
+    ).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(typ, chain.get(1), self._page);
+    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, typ: []const u8, mouse: MouseEvent, child: anytype) !*@TypeOf(child) {
-    const allocator = self._slab.allocator();
-
+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(allocator);
+    ).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(typ, chain.get(1), self._page);
+    event_ptr.* = try self.eventInit(arena, typ, chain.get(1));
     chain.setMiddle(1, UIEvent.Type);
 
     // Set MouseEvent with all its fields
@@ -239,6 +231,20 @@ pub fn mouseEvent(self: *Factory, typ: []const u8, mouse: MouseEvent, child: any
     return chain.get(3);
 }
 
+fn eventInit(self: *const Factory, 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 .{
+        ._arena = arena,
+        ._page = self._page,
+        ._type = unionInit(Event.Type, value),
+        ._type_string = typ,
+        ._time_stamp = time_stamp,
+    };
+}
+
 pub fn blob(self: *Factory, child: anytype) !*@TypeOf(child) {
     const allocator = self._slab.allocator();
 
@@ -333,7 +339,7 @@ pub fn svgElement(self: *Factory, tag_name: []const u8, child: anytype) !*@TypeO
     chain.setMiddle(2, Element.Type);
 
     // will never allocate, can't fail
-    const tag_name_str = String.init(self._page.arena, tag_name, .{}) catch unreachable;
+    const tag_name_str = String.init(self._arena, tag_name, .{}) catch unreachable;
 
     // Manually set Element.Svg with the tag_name
     chain.set(3, .{

src/browser/Mime.zig

@@ -38,6 +38,10 @@ pub const ContentTypeEnum = enum {
     text_javascript,
     text_plain,
     text_css,
+    image_jpeg,
+    image_gif,
+    image_png,
+    image_webp,
     application_json,
     unknown,
     other,
@@ -49,6 +53,10 @@ pub const ContentType = union(ContentTypeEnum) {
     text_javascript: void,
     text_plain: void,
     text_css: void,
+    image_jpeg: void,
+    image_gif: void,
+    image_png: void,
+    image_webp: void,
     application_json: void,
     unknown: void,
     other: struct { type: []const u8, sub_type: []const u8 },
@@ -61,6 +69,10 @@ pub fn contentTypeString(mime: *const Mime) []const u8 {
         .text_javascript => "application/javascript",
         .text_plain => "text/plain",
         .text_css => "text/css",
+        .image_jpeg => "image/jpeg",
+        .image_png => "image/png",
+        .image_gif => "image/gif",
+        .image_webp => "image/webp",
         .application_json => "application/json",
         else => "",
     };
@@ -243,6 +255,11 @@ fn parseContentType(value: []const u8) !struct { ContentType, usize } {
         @"application/javascript",
         @"application/x-javascript",
 
+        @"image/jpeg",
+        @"image/png",
+        @"image/gif",
+        @"image/webp",
+
         @"application/json",
     }, type_name)) |known_type| {
         const ct: ContentType = switch (known_type) {
@@ -251,6 +268,10 @@ fn parseContentType(value: []const u8) !struct { ContentType, usize } {
             .@"text/javascript", .@"application/javascript", .@"application/x-javascript" => .{ .text_javascript = {} },
             .@"text/plain" => .{ .text_plain = {} },
             .@"text/css" => .{ .text_css = {} },
+            .@"image/jpeg" => .{ .image_jpeg = {} },
+            .@"image/png" => .{ .image_png = {} },
+            .@"image/gif" => .{ .image_gif = {} },
+            .@"image/webp" => .{ .image_webp = {} },
             .@"application/json" => .{ .application_json = {} },
         };
         return .{ ct, attribute_start };
@@ -358,6 +379,11 @@ test "Mime: parse common" {
 
     try expect(.{ .content_type = .{ .application_json = {} } }, "application/json");
     try expect(.{ .content_type = .{ .text_css = {} } }, "text/css");
+
+    try expect(.{ .content_type = .{ .image_jpeg = {} } }, "image/jpeg");
+    try expect(.{ .content_type = .{ .image_png = {} } }, "image/png");
+    try expect(.{ .content_type = .{ .image_gif = {} } }, "image/gif");
+    try expect(.{ .content_type = .{ .image_webp = {} } }, "image/webp");
 }
 
 test "Mime: parse uncommon" {

src/browser/ScriptManager.zig

@@ -31,7 +31,7 @@ const Http = @import("../http/Http.zig");
 const Element = @import("webapi/Element.zig");
 
 const Allocator = std.mem.Allocator;
-const ArrayListUnmanaged = std.ArrayListUnmanaged;
+const ArrayList = std.ArrayList;
 
 const IS_DEBUG = builtin.mode == .Debug;
 
@@ -83,10 +83,7 @@ imported_modules: std.StringHashMapUnmanaged(ImportedModule),
 // importmap contains resolved urls.
 importmap: std.StringHashMapUnmanaged([:0]const u8),
 
-pub fn init(page: *Page) ScriptManager {
-    // page isn't fully initialized, we can setup our reference, but that's it.
-    const browser = page._session.browser;
-    const allocator = browser.allocator;
+pub fn init(allocator: Allocator, http_client: *Http.Client, page: *Page) ScriptManager {
     return .{
         .page = page,
         .async_scripts = .{},
@@ -96,7 +93,7 @@ pub fn init(page: *Page) ScriptManager {
         .is_evaluating = false,
         .allocator = allocator,
         .imported_modules = .empty,
-        .client = browser.http_client,
+        .client = http_client,
         .static_scripts_done = false,
         .buffer_pool = BufferPool.init(allocator, 5),
         .script_pool = std.heap.MemoryPool(Script).init(allocator),
@@ -138,6 +135,12 @@ fn clearList(list: *std.DoublyLinkedList) void {
     }
 }
 
+pub fn getHeaders(self: *ScriptManager, url: [:0]const u8) !Http.Headers {
+    var headers = try self.client.newHeaders();
+    try self.page.headersForRequest(self.page.arena, url, &headers);
+    return headers;
+}
+
 pub fn addFromElement(self: *ScriptManager, comptime from_parser: bool, script_element: *Element.Html.Script, comptime ctx: []const u8) !void {
     if (script_element._executed) {
         // If a script tag gets dynamically created and added to the dom:
@@ -252,17 +255,15 @@ pub fn addFromElement(self: *ScriptManager, comptime from_parser: bool, script_e
             script.deinit(true);
         }
 
-        var headers = try self.client.newHeaders();
-        try page.requestCookie(.{}).headersForRequest(page.arena, url, &headers);
-
         try self.client.request(.{
             .url = url,
             .ctx = script,
             .method = .GET,
-            .headers = headers,
+            .headers = try self.getHeaders(url),
             .blocking = is_blocking,
             .cookie_jar = &page._session.cookie_jar,
             .resource_type = .script,
+            .notification = page._session.notification,
             .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
             .header_callback = Script.headerCallback,
             .data_callback = Script.dataCallback,
@@ -357,9 +358,6 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .manager = self,
     };
 
-    var headers = try self.client.newHeaders();
-    try self.page.requestCookie(.{}).headersForRequest(self.page.arena, url, &headers);
-
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
         self.page.js.localScope(&ls);
@@ -377,9 +375,10 @@ pub fn preloadImport(self: *ScriptManager, url: [:0]const u8, referrer: []const
         .url = url,
         .ctx = script,
         .method = .GET,
-        .headers = headers,
+        .headers = try self.getHeaders(url),
         .cookie_jar = &self.page._session.cookie_jar,
         .resource_type = .script,
+        .notification = self.page._session.notification,
         .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
         .header_callback = Script.headerCallback,
         .data_callback = Script.dataCallback,
@@ -452,9 +451,6 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
         } },
     };
 
-    var headers = try self.client.newHeaders();
-    try self.page.requestCookie(.{}).headersForRequest(self.page.arena, url, &headers);
-
     if (comptime IS_DEBUG) {
         var ls: js.Local.Scope = undefined;
         self.page.js.localScope(&ls);
@@ -480,10 +476,11 @@ pub fn getAsyncImport(self: *ScriptManager, url: [:0]const u8, cb: ImportAsync.C
     try self.client.request(.{
         .url = url,
         .method = .GET,
-        .headers = headers,
+        .headers = try self.getHeaders(url),
         .ctx = script,
         .resource_type = .script,
         .cookie_jar = &self.page._session.cookie_jar,
+        .notification = self.page._session.notification,
         .start_callback = if (log.enabled(.http, .debug)) Script.startCallback else null,
         .header_callback = Script.headerCallback,
         .data_callback = Script.dataCallback,
@@ -620,6 +617,7 @@ pub const Script = struct {
     node: std.DoublyLinkedList.Node,
     script_element: ?*Element.Html.Script,
     manager: *ScriptManager,
+    header_callback_called: bool = false,
 
     const Kind = enum {
         module,
@@ -634,7 +632,7 @@ pub const Script = struct {
 
     const Source = union(enum) {
         @"inline": []const u8,
-        remote: std.ArrayListUnmanaged(u8),
+        remote: std.ArrayList(u8),
 
         fn content(self: Source) []const u8 {
             return switch (self) {
@@ -684,11 +682,15 @@ pub const Script = struct {
             });
         }
 
-        // If this isn't true, then we'll likely leak memory. If you don't
-        // set `CURLOPT_SUPPRESS_CONNECT_HEADERS` and CONNECT to a proxy, this
-        // will fail. This assertion exists to catch incorrect assumptions about
-        // how libcurl works, or about how we've configured it.
-        lp.assert(self.source.remote.capacity == 0, "ScriptManager.HeaderCallback", .{ .capacity = self.source.remote.capacity });
+        {
+            // 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", .{});
+            self.header_callback_called = true;
+        }
+
+        lp.assert(self.source.remote.capacity == 0, "ScriptManager.Header buffer", .{ .capacity = self.source.remote.capacity });
         var buffer = self.manager.buffer_pool.get();
         if (transfer.getContentLength()) |cl| {
             try buffer.ensureTotalCapacity(self.manager.allocator, cl);
@@ -849,7 +851,7 @@ pub const Script = struct {
         defer {
             // We should run microtasks even if script execution fails.
             local.runMicrotasks();
-            _ = page.scheduler.run() catch |err| {
+            _ = page.js.scheduler.run() catch |err| {
                 log.err(.page, "scheduler", .{ .err = err });
             };
         }
@@ -873,7 +875,7 @@ pub const Script = struct {
         const cb = cb_ orelse return;
 
         const Event = @import("webapi/Event.zig");
-        const event = Event.initTrusted(typ, .{}, page) catch |err| {
+        const event = Event.initTrusted(comptime .wrap(typ), .{}, page) catch |err| {
             log.warn(.js, "script internal callback", .{
                 .url = self.url,
                 .type = typ,
@@ -881,6 +883,7 @@ 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 {
@@ -900,11 +903,11 @@ const BufferPool = struct {
     max_concurrent_transfers: u8,
     mem_pool: std.heap.MemoryPool(Container),
 
-    const List = std.DoublyLinkedList;
+    const List = std.SinglyLinkedList;
 
     const Container = struct {
         node: List.Node,
-        buf: std.ArrayListUnmanaged(u8),
+        buf: std.ArrayList(u8),
     };
 
     fn init(allocator: Allocator, max_concurrent_transfers: u8) BufferPool {
@@ -929,7 +932,7 @@ const BufferPool = struct {
         self.mem_pool.deinit();
     }
 
-    fn get(self: *BufferPool) std.ArrayListUnmanaged(u8) {
+    fn get(self: *BufferPool) std.ArrayList(u8) {
         const node = self.available.popFirst() orelse {
             // return a new buffer
             return .{};
@@ -941,7 +944,7 @@ const BufferPool = struct {
         return container.buf;
     }
 
-    fn release(self: *BufferPool, buffer: ArrayListUnmanaged(u8)) void {
+    fn release(self: *BufferPool, buffer: ArrayList(u8)) void {
         // create mutable copy
         var b = buffer;
 
@@ -959,7 +962,7 @@ const BufferPool = struct {
         b.clearRetainingCapacity();
         container.* = .{ .buf = b, .node = .{} };
         self.count += 1;
-        self.available.append(&container.node);
+        self.available.prepend(&container.node);
     }
 };
 

src/browser/Session.zig

@@ -28,6 +28,7 @@ const History = @import("webapi/History.zig");
 
 const Page = @import("Page.zig");
 const Browser = @import("Browser.zig");
+const Notification = @import("../Notification.zig");
 
 const Allocator = std.mem.Allocator;
 const IS_DEBUG = @import("builtin").mode == .Debug;
@@ -39,6 +40,7 @@ const IS_DEBUG = @import("builtin").mode == .Debug;
 const Session = @This();
 
 browser: *Browser,
+notification: *Notification,
 
 // Used to create our Inspector and in the BrowserContext.
 arena: Allocator,
@@ -53,31 +55,33 @@ arena: Allocator,
 // page and start another.
 transfer_arena: Allocator,
 
-executor: js.ExecutionWorld,
 cookie_jar: storage.Cookie.Jar,
 storage_shed: storage.Shed,
 
 history: History,
 navigation: Navigation,
 
-page: ?*Page = null,
-
-pub fn init(self: *Session, browser: *Browser) !void {
-    var executor = try browser.env.newExecutionWorld();
-    errdefer executor.deinit();
+page: ?Page,
 
+pub fn init(self: *Session, browser: *Browser, notification: *Notification) !void {
     const allocator = browser.app.allocator;
-    const session_allocator = browser.session_arena.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.* = .{
-        .browser = browser,
-        .executor = executor,
-        .storage_shed = .{},
-        .arena = session_allocator,
-        .cookie_jar = storage.Cookie.Jar.init(allocator),
-        .navigation = .{},
+        .page = null,
+        .arena = arena,
         .history = .{},
-        .transfer_arena = browser.transfer_arena.allocator(),
+        // 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),
     };
 }
 
@@ -85,9 +89,12 @@ pub fn deinit(self: *Session) void {
     if (self.page != null) {
         self.removePage();
     }
+    const browser = self.browser;
+
     self.cookie_jar.deinit();
-    self.storage_shed.deinit(self.browser.app.allocator);
-    self.executor.deinit();
+    self.storage_shed.deinit(browser.app.allocator);
+    browser.arena_pool.release(self.transfer_arena);
+    browser.arena_pool.release(self.arena);
 }
 
 // NOTE: the caller is not the owner of the returned value,
@@ -95,11 +102,9 @@ pub fn deinit(self: *Session) void {
 pub fn createPage(self: *Session) !*Page {
     lp.assert(self.page == null, "Session.createPage - page not null", .{});
 
-    const page_arena = &self.browser.page_arena;
-    _ = page_arena.reset(.{ .retain_with_limit = 1 * 1024 * 1024 });
-
-    self.page = try Page.init(page_arena.allocator(), self.browser.call_arena.allocator(), self);
-    const page = self.page.?;
+    self.page = @as(Page, undefined);
+    const page = &self.page.?;
+    try Page.init(page, self);
 
     // Creates a new NavigationEventTarget for this page.
     try self.navigation.onNewPage(page);
@@ -109,14 +114,14 @@ pub fn createPage(self: *Session) !*Page {
     }
     // start JS env
     // Inform CDP the main page has been created such that additional context for other Worlds can be created as well
-    self.browser.notification.dispatch(.page_created, page);
+    self.notification.dispatch(.page_created, page);
 
     return page;
 }
 
 pub fn removePage(self: *Session) void {
     // Inform CDP the page is going to be removed, allowing other worlds to remove themselves before the main one
-    self.browser.notification.dispatch(.page_remove, .{});
+    self.notification.dispatch(.page_remove, .{});
     lp.assert(self.page != null, "Session.removePage - page is null", .{});
 
     self.page.?.deinit();
@@ -129,23 +134,45 @@ pub fn removePage(self: *Session) void {
     }
 }
 
+pub fn replacePage(self: *Session) !*Page {
+    if (comptime IS_DEBUG) {
+        log.debug(.browser, "replace page", .{});
+    }
+
+    lp.assert(self.page != null, "Session.replacePage null page", .{});
+    self.page.?.deinit();
+    self.browser.env.memoryPressureNotification(.moderate);
+
+    self.page = @as(Page, undefined);
+    const page = &self.page.?;
+    try Page.init(page, self);
+    return page;
+}
+
 pub fn currentPage(self: *Session) ?*Page {
-    return self.page orelse return null;
+    return &(self.page orelse return null);
 }
 
 pub const WaitResult = enum {
     done,
     no_page,
     cdp_socket,
-    navigate,
 };
 
 pub fn wait(self: *Session, wait_ms: u32) WaitResult {
     while (true) {
-        const page = self.page orelse return .no_page;
-        switch (page.wait(wait_ms)) {
-            .navigate => self.processScheduledNavigation() catch return .done,
-            else => |result| return result,
+        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,
+            }
+        } else {
+            return .no_page;
         }
         // if we've successfull navigated, we'll give the new page another
         // page.wait(wait_ms)
@@ -153,24 +180,32 @@ pub fn wait(self: *Session, wait_ms: u32) WaitResult {
 }
 
 fn processScheduledNavigation(self: *Session) !void {
-    const qn = self.page.?._queued_navigation.?;
-    defer _ = self.browser.transfer_arena.reset(.{ .retain_with_limit = 8 * 1024 });
+    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;
 
-    // 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();
-    self.removePage();
+        // 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();
+        self.removePage();
+
+        break :blk .{ url, opts };
+    };
 
     const page = self.createPage() catch |err| {
         log.err(.browser, "queued navigation page error", .{
             .err = err,
-            .url = qn.url,
+            .url = url,
         });
         return err;
     };
 
-    page.navigate(qn.url, qn.opts) catch |err| {
-        log.err(.browser, "queued navigation error", .{ .err = err, .url = qn.url });
+    page.navigate(url, opts) catch |err| {
+        log.err(.browser, "queued navigation error", .{ .err = err, .url = url });
         return err;
     };
 }

src/browser/URL.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -17,7 +17,6 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
-const lp = @import("lightpanda");
 const Allocator = std.mem.Allocator;
 
 const ResolveOpts = struct {
@@ -503,6 +502,16 @@ pub fn concatQueryString(arena: Allocator, url: []const u8, query_string: []cons
     return buf.items[0 .. buf.items.len - 1 :0];
 }
 
+pub fn getRobotsUrl(arena: Allocator, url: [:0]const u8) ![:0]const u8 {
+    const origin = try getOrigin(arena, url) orelse return error.NoOrigin;
+    return try std.fmt.allocPrintSentinel(
+        arena,
+        "{s}/robots.txt",
+        .{origin},
+        0,
+    );
+}
+
 const testing = @import("../testing.zig");
 test "URL: isCompleteHTTPUrl" {
     try testing.expectEqual(true, isCompleteHTTPUrl("http://example.com/about"));
@@ -779,3 +788,31 @@ test "URL: concatQueryString" {
         try testing.expectEqual("https://www.lightpanda.io/index?1=2&a=b", url);
     }
 }
+
+test "URL: getRobotsUrl" {
+    defer testing.reset();
+    const arena = testing.arena_allocator;
+
+    {
+        const url = try getRobotsUrl(arena, "https://www.lightpanda.io");
+        try testing.expectEqual("https://www.lightpanda.io/robots.txt", url);
+    }
+
+    {
+        const url = try getRobotsUrl(arena, "https://www.lightpanda.io/some/path");
+        try testing.expectString("https://www.lightpanda.io/robots.txt", url);
+    }
+
+    {
+        const url = try getRobotsUrl(arena, "https://www.lightpanda.io:8080/page");
+        try testing.expectString("https://www.lightpanda.io:8080/robots.txt", url);
+    }
+    {
+        const url = try getRobotsUrl(arena, "http://example.com/deep/nested/path?query=value#fragment");
+        try testing.expectString("http://example.com/robots.txt", url);
+    }
+    {
+        const url = try getRobotsUrl(arena, "https://user:pass@example.com/page");
+        try testing.expectString("https://example.com/robots.txt", url);
+    }
+}

src/browser/js/Caller.zig

@@ -23,39 +23,40 @@ const string = @import("../../string.zig");
 const Page = @import("../Page.zig");
 
 const js = @import("js.zig");
-const bridge = @import("bridge.zig");
+const Local = @import("Local.zig");
 const Context = @import("Context.zig");
 const TaggedOpaque = @import("TaggedOpaque.zig");
 
 const v8 = js.v8;
-const Allocator = std.mem.Allocator;
 const ArenaAllocator = std.heap.ArenaAllocator;
 
 const CALL_ARENA_RETAIN = 1024 * 16;
 const IS_DEBUG = @import("builtin").mode == .Debug;
 
 const Caller = @This();
-local: js.Local,
+local: Local,
 prev_local: ?*const js.Local,
+prev_context: *Context,
 
 // Takes the raw v8 isolate and extracts the context from it.
 pub fn init(self: *Caller, v8_isolate: *v8.Isolate) void {
-    const v8_context_handle = v8.v8__Isolate__GetCurrentContext(v8_isolate);
-
-    const embedder_data = v8.v8__Context__GetEmbedderData(v8_context_handle, 1);
-    var lossless: bool = undefined;
-    const ctx: *Context = @ptrFromInt(v8.v8__BigInt__Uint64Value(embedder_data, &lossless));
+    const v8_context = v8.v8__Isolate__GetCurrentContext(v8_isolate).?;
+    initWithContext(self, Context.fromC(v8_context), v8_context);
+}
 
+fn initWithContext(self: *Caller, ctx: *Context, v8_context: *const v8.Context) void {
     ctx.call_depth += 1;
     self.* = Caller{
         .local = .{
             .ctx = ctx,
-            .handle = v8_context_handle.?,
+            .handle = v8_context,
             .call_arena = ctx.call_arena,
-            .isolate = .{ .handle = v8_isolate },
+            .isolate = ctx.isolate,
         },
         .prev_local = ctx.local,
+        .prev_context = ctx.page.js,
     };
+    ctx.page.js = ctx;
     ctx.local = &self.local;
 }
 
@@ -81,35 +82,38 @@ pub fn deinit(self: *Caller) void {
 
     ctx.call_depth = call_depth;
     ctx.local = self.prev_local;
+    ctx.page.js = self.prev_context;
 }
 
 pub const CallOpts = struct {
-    cache: ?[]const u8 = null,
     dom_exception: bool = false,
     null_as_undefined: bool = false,
     as_typed_array: bool = false,
 };
 
 pub fn constructor(self: *Caller, comptime T: type, func: anytype, handle: *const v8.FunctionCallbackInfo, comptime opts: CallOpts) void {
+    const local = &self.local;
+
     var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
+    hs.init(local.isolate);
     defer hs.deinit();
 
     const info = FunctionCallbackInfo{ .handle = handle };
 
     if (!info.isConstructCall()) {
-        self.handleError(T, @TypeOf(func), error.InvalidArgument, info, opts);
+        handleError(T, @TypeOf(func), local, error.InvalidArgument, info, opts);
         return;
     }
 
     self._constructor(func, info) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
+        handleError(T, @TypeOf(func), local, err, info, opts);
     };
 }
 
 fn _constructor(self: *Caller, func: anytype, info: FunctionCallbackInfo) !void {
     const F = @TypeOf(func);
-    const args = try self.getArgs(F, 0, info);
+    const local = &self.local;
+    const args = try getArgs(F, 0, local, info);
     const res = @call(.auto, func, args);
 
     const ReturnType = @typeInfo(F).@"fn".return_type orelse {
@@ -117,12 +121,12 @@ fn _constructor(self: *Caller, func: anytype, info: FunctionCallbackInfo) !void
     };
 
     const new_this_handle = info.getThis();
-    var this = js.Object{ .local = &self.local, .handle = new_this_handle };
+    var this = js.Object{ .local = local, .handle = new_this_handle };
     if (@typeInfo(ReturnType) == .error_union) {
         const non_error_res = res catch |err| return err;
-        this = try self.local.mapZigInstanceToJs(new_this_handle, non_error_res);
+        this = try local.mapZigInstanceToJs(new_this_handle, non_error_res);
     } else {
-        this = try self.local.mapZigInstanceToJs(new_this_handle, res);
+        this = try local.mapZigInstanceToJs(new_this_handle, res);
     }
 
     // If we got back a different object (existing wrapper), copy the prototype
@@ -139,144 +143,115 @@ fn _constructor(self: *Caller, func: anytype, info: FunctionCallbackInfo) !void
     info.getReturnValue().set(this.handle);
 }
 
-pub fn method(self: *Caller, comptime T: type, func: anytype, handle: *const v8.FunctionCallbackInfo, comptime opts: CallOpts) void {
-    var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
-    defer hs.deinit();
-
-    const info = FunctionCallbackInfo{ .handle = handle };
-    self._method(T, func, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
-    };
-}
-
-fn _method(self: *Caller, comptime T: type, func: anytype, info: FunctionCallbackInfo, comptime opts: CallOpts) !void {
-    const F = @TypeOf(func);
-    var args = try self.getArgs(F, 1, info);
-
-    const js_this = info.getThis();
-    @field(args, "0") = try TaggedOpaque.fromJS(*T, js_this);
-
-    const res = @call(.auto, func, args);
-
-    const mapped = try self.local.zigValueToJs(res, opts);
-    const return_value = info.getReturnValue();
-    return_value.set(mapped);
-}
-
-pub fn function(self: *Caller, comptime T: type, func: anytype, handle: *const v8.FunctionCallbackInfo, comptime opts: CallOpts) void {
-    var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
-    defer hs.deinit();
-
-    const info = FunctionCallbackInfo{ .handle = handle };
-    self._function(func, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
-    };
-}
-
-fn _function(self: *Caller, func: anytype, info: FunctionCallbackInfo, comptime opts: CallOpts) !void {
-    const F = @TypeOf(func);
-    const args = try self.getArgs(F, 0, info);
-    const res = @call(.auto, func, args);
-    info.getReturnValue().set(try self.local.zigValueToJs(res, opts));
-}
-
 pub fn getIndex(self: *Caller, comptime T: type, func: anytype, idx: u32, handle: *const v8.PropertyCallbackInfo, comptime opts: CallOpts) u8 {
+    const local = &self.local;
+
     var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
+    hs.init(local.isolate);
     defer hs.deinit();
 
     const info = PropertyCallbackInfo{ .handle = handle };
-    return self._getIndex(T, func, idx, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
+    return _getIndex(T, local, func, idx, info, opts) catch |err| {
+        handleError(T, @TypeOf(func), local, err, info, opts);
         // not intercepted
         return 0;
     };
 }
 
-fn _getIndex(self: *Caller, comptime T: type, func: anytype, idx: u32, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+fn _getIndex(comptime T: type, local: *const Local, func: anytype, idx: u32, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
     const F = @TypeOf(func);
-    var args = try self.getArgs(F, 2, info);
+    var args: ParameterTypes(F) = undefined;
     @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
     @field(args, "1") = idx;
+    if (@typeInfo(F).@"fn".params.len == 3) {
+        @field(args, "2") = local.ctx.page;
+    }
     const ret = @call(.auto, func, args);
-    return self.handleIndexedReturn(T, F, true, ret, info, opts);
+    return handleIndexedReturn(T, F, true, local, ret, info, opts);
 }
 
 pub fn getNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, handle: *const v8.PropertyCallbackInfo, comptime opts: CallOpts) u8 {
+    const local = &self.local;
+
     var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
+    hs.init(local.isolate);
     defer hs.deinit();
 
     const info = PropertyCallbackInfo{ .handle = handle };
-    return self._getNamedIndex(T, func, name, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
+    return _getNamedIndex(T, local, func, name, info, opts) catch |err| {
+        handleError(T, @TypeOf(func), local, err, info, opts);
         // not intercepted
         return 0;
     };
 }
 
-fn _getNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+fn _getNamedIndex(comptime T: type, local: *const Local, func: anytype, name: *const v8.Name, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
     const F = @TypeOf(func);
-    var args = try self.getArgs(F, 2, info);
+    var args: ParameterTypes(F) = undefined;
     @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
-    @field(args, "1") = try self.nameToString(@TypeOf(args.@"1"), name);
+    @field(args, "1") = try nameToString(local, @TypeOf(args.@"1"), name);
+    if (@typeInfo(F).@"fn".params.len == 3) {
+        @field(args, "2") = local.ctx.page;
+    }
     const ret = @call(.auto, func, args);
-    return self.handleIndexedReturn(T, F, true, ret, info, opts);
+    return handleIndexedReturn(T, F, true, local, ret, info, opts);
 }
 
 pub fn setNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, js_value: *const v8.Value, handle: *const v8.PropertyCallbackInfo, comptime opts: CallOpts) u8 {
+    const local = &self.local;
+
     var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
+    hs.init(local.isolate);
     defer hs.deinit();
 
     const info = PropertyCallbackInfo{ .handle = handle };
-    return self._setNamedIndex(T, func, name, .{ .local = &self.local, .handle = js_value }, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
+    return _setNamedIndex(T, local, func, name, .{ .local = &self.local, .handle = js_value }, info, opts) catch |err| {
+        handleError(T, @TypeOf(func), local, err, info, opts);
         // not intercepted
         return 0;
     };
 }
 
-fn _setNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, js_value: js.Value, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+fn _setNamedIndex(comptime T: type, local: *const Local, func: anytype, name: *const v8.Name, js_value: js.Value, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
     const F = @TypeOf(func);
     var args: ParameterTypes(F) = undefined;
     @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
-    @field(args, "1") = try self.nameToString(@TypeOf(args.@"1"), name);
-    @field(args, "2") = try self.local.jsValueToZig(@TypeOf(@field(args, "2")), js_value);
+    @field(args, "1") = try nameToString(local, @TypeOf(args.@"1"), name);
+    @field(args, "2") = try local.jsValueToZig(@TypeOf(@field(args, "2")), js_value);
     if (@typeInfo(F).@"fn".params.len == 4) {
-        @field(args, "3") = self.local.ctx.page;
+        @field(args, "3") = local.ctx.page;
     }
     const ret = @call(.auto, func, args);
-    return self.handleIndexedReturn(T, F, false, ret, info, opts);
+    return handleIndexedReturn(T, F, false, local, ret, info, opts);
 }
 
 pub fn deleteNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, handle: *const v8.PropertyCallbackInfo, comptime opts: CallOpts) u8 {
+    const local = &self.local;
+
     var hs: js.HandleScope = undefined;
-    hs.init(self.local.isolate);
+    hs.init(local.isolate);
     defer hs.deinit();
 
     const info = PropertyCallbackInfo{ .handle = handle };
-    return self._deleteNamedIndex(T, func, name, info, opts) catch |err| {
-        self.handleError(T, @TypeOf(func), err, info, opts);
+    return _deleteNamedIndex(T, local, func, name, info, opts) catch |err| {
+        handleError(T, @TypeOf(func), local, err, info, opts);
         return 0;
     };
 }
 
-fn _deleteNamedIndex(self: *Caller, comptime T: type, func: anytype, name: *const v8.Name, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+fn _deleteNamedIndex(comptime T: type, local: *const Local, func: anytype, name: *const v8.Name, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
     const F = @TypeOf(func);
     var args: ParameterTypes(F) = undefined;
     @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
-    @field(args, "1") = try self.nameToString(@TypeOf(args.@"1"), name);
+    @field(args, "1") = try nameToString(local, @TypeOf(args.@"1"), name);
     if (@typeInfo(F).@"fn".params.len == 3) {
-        @field(args, "2") = self.local.ctx.page;
+        @field(args, "2") = local.ctx.page;
     }
     const ret = @call(.auto, func, args);
-    return self.handleIndexedReturn(T, F, false, ret, info, opts);
+    return handleIndexedReturn(T, F, false, local, ret, info, opts);
 }
 
-fn handleIndexedReturn(self: *Caller, comptime T: type, comptime F: type, comptime getter: bool, ret: anytype, info: PropertyCallbackInfo, comptime opts: CallOpts) !u8 {
+fn handleIndexedReturn(comptime T: type, comptime F: type, comptime getter: 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))) {
@@ -291,7 +266,7 @@ fn handleIndexedReturn(self: *Caller, comptime T: type, comptime F: type, compti
                         return 0;
                     }
                 }
-                self.handleError(T, F, err, info, opts);
+                handleError(T, F, local, err, info, opts);
                 // not intercepted
                 return 0;
             };
@@ -300,7 +275,7 @@ fn handleIndexedReturn(self: *Caller, comptime T: type, comptime F: type, compti
     };
 
     if (comptime getter) {
-        info.getReturnValue().set(try self.local.zigValueToJs(non_error_ret, opts));
+        info.getReturnValue().set(try local.zigValueToJs(non_error_ret, opts));
     }
     // intercepted
     return 1;
@@ -313,27 +288,28 @@ fn isInErrorSet(err: anyerror, comptime T: type) bool {
     return false;
 }
 
-fn nameToString(self: *const Caller, comptime T: type, name: *const v8.Name) !T {
-    const v8_string = @as(*const v8.String, @ptrCast(name));
+fn nameToString(local: *const Local, comptime T: type, name: *const v8.Name) !T {
+    const handle = @as(*const v8.String, @ptrCast(name));
     if (T == string.String) {
-        return self.local.jsStringToStringSSO(v8_string, .{});
+        return js.String.toSSO(.{ .local = local, .handle = handle }, false);
     }
     if (T == string.Global) {
-        return self.local.jsStringToStringSSO(v8_string, .{ .allocator = self.local.ctx.allocator });
+        return js.String.toSSO(.{ .local = local, .handle = handle }, true);
     }
-    return try self.local.valueHandleToString(v8_string, .{});
+    return try js.String.toSlice(.{ .local = local, .handle = handle });
 }
 
-fn handleError(self: *Caller, comptime T: type, comptime F: type, err: anyerror, info: anytype, comptime opts: CallOpts) void {
-    const isolate = self.local.isolate;
+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)) {
-            self.logFunctionCallError(@typeName(T), @typeName(F), err, info);
+            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.OutOfMemory => isolate.createError("out of memory"),
         error.IllegalConstructor => isolate.createError("Illegal Contructor"),
@@ -341,7 +317,7 @@ fn handleError(self: *Caller, comptime T: type, comptime F: type, err: anyerror,
             if (comptime opts.dom_exception) {
                 const DOMException = @import("../webapi/DOMException.zig");
                 if (DOMException.fromError(err)) |ex| {
-                    const value = self.local.zigValueToJs(ex, .{}) catch break :blk isolate.createError("internal error");
+                    const value = local.zigValueToJs(ex, .{}) catch break :blk isolate.createError("internal error");
                     break :blk value.handle;
                 }
             }
@@ -353,120 +329,20 @@ fn handleError(self: *Caller, comptime T: type, comptime F: type, err: anyerror,
     info.getReturnValue().setValueHandle(js_exception);
 }
 
-// If we call a method in javascript: cat.lives('nine');
-//
-// Then we'd expect a Zig function with 2 parameters: a self and the string.
-// In this case, offset == 1. Offset is always 1 for setters or methods.
-//
-// Offset is always 0 for constructors.
-//
-// For constructors, setters and methods, we can further increase offset + 1
-// if the first parameter is an instance of Page.
-//
-// Finally, if the JS function is called with _more_ parameters and
-// the last parameter in Zig is an array, we'll try to slurp the additional
-// parameters into the array.
-fn getArgs(self: *const Caller, comptime F: type, comptime offset: usize, info: anytype) !ParameterTypes(F) {
-    const local = &self.local;
-    var args: ParameterTypes(F) = undefined;
-
-    const params = @typeInfo(F).@"fn".params[offset..];
-    // Except for the constructor, the first parameter is always `self`
-    // This isn't something we'll bind from JS, so skip it.
-    const params_to_map = blk: {
-        if (params.len == 0) {
-            return args;
-        }
-
-        // If the last parameter is the Page, set it, and exclude it
-        // from our params slice, because we don't want to bind it to
-        // a JS argument
-        if (comptime isPage(params[params.len - 1].type.?)) {
-            @field(args, tupleFieldName(params.len - 1 + offset)) = local.ctx.page;
-            break :blk params[0 .. params.len - 1];
-        }
-
-        // we have neither a Page nor a JsObject. All params must be
-        // bound to a JavaScript value.
-        break :blk params;
-    };
-
-    if (params_to_map.len == 0) {
-        return args;
-    }
-
-    const js_parameter_count = info.length();
-    const last_js_parameter = params_to_map.len - 1;
-    var is_variadic = false;
-
-    {
-        // This is going to get complicated. If the last Zig parameter
-        // is a slice AND the corresponding javascript parameter is
-        // NOT an an array, then we'll treat it as a variadic.
-
-        const last_parameter_type = params_to_map[params_to_map.len - 1].type.?;
-        const last_parameter_type_info = @typeInfo(last_parameter_type);
-        if (last_parameter_type_info == .pointer and last_parameter_type_info.pointer.size == .slice) {
-            const slice_type = last_parameter_type_info.pointer.child;
-            const corresponding_js_value = info.getArg(@intCast(last_js_parameter), local);
-            if (corresponding_js_value.isArray() == false and corresponding_js_value.isTypedArray() == false and slice_type != u8) {
-                is_variadic = true;
-                if (js_parameter_count == 0) {
-                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = &.{};
-                } else if (js_parameter_count >= params_to_map.len) {
-                    const arr = try local.call_arena.alloc(last_parameter_type_info.pointer.child, js_parameter_count - params_to_map.len + 1);
-                    for (arr, last_js_parameter..) |*a, i| {
-                        a.* = try local.jsValueToZig(slice_type, info.getArg(@intCast(i), local));
-                    }
-                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = arr;
-                } else {
-                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = &.{};
-                }
-            }
-        }
-    }
-
-    inline for (params_to_map, 0..) |param, i| {
-        const field_index = comptime i + offset;
-        if (comptime i == params_to_map.len - 1) {
-            if (is_variadic) {
-                break;
-            }
-        }
-
-        if (comptime isPage(param.type.?)) {
-            @compileError("Page must be the last parameter (or 2nd last if there's a JsThis): " ++ @typeName(F));
-        } else if (i >= js_parameter_count) {
-            if (@typeInfo(param.type.?) != .optional) {
-                return error.InvalidArgument;
-            }
-            @field(args, tupleFieldName(field_index)) = null;
-        } else {
-            const js_val = info.getArg(@intCast(i), local);
-            @field(args, tupleFieldName(field_index)) = local.jsValueToZig(param.type.?, js_val) catch {
-                return error.InvalidArgument;
-            };
-        }
-    }
-
-    return args;
-}
-
 // This is extracted to speed up compilation. When left inlined in handleError,
 // this can add as much as 10 seconds of compilation time.
-fn logFunctionCallError(self: *Caller, type_name: []const u8, func: []const u8, err: anyerror, info: FunctionCallbackInfo) void {
-    const args_dump = self.serializeFunctionArgs(info) catch "failed to serialize args";
+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", .{
         .type = type_name,
         .func = func,
         .err = err,
         .args = args_dump,
-        .stack = self.local.stackTrace() catch |err1| @errorName(err1),
+        .stack = local.stackTrace() catch |err1| @errorName(err1),
     });
 }
 
-fn serializeFunctionArgs(self: *Caller, info: FunctionCallbackInfo) ![]const u8 {
-    const local = &self.local;
+fn serializeFunctionArgs(local: *const Local, info: FunctionCallbackInfo) ![]const u8 {
     var buf = std.Io.Writer.Allocating.init(local.call_arena);
 
     const separator = log.separator();
@@ -583,3 +459,274 @@ const ReturnValue = struct {
         v8.v8__ReturnValue__Set(self.handle, handle);
     }
 };
+
+pub const Function = struct {
+    pub const Opts = struct {
+        static: bool = false,
+        dom_exception: bool = false,
+        as_typed_array: bool = false,
+        null_as_undefined: bool = false,
+        cache: ?Caching = null,
+
+        // 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
+        // and a Struct.
+        // 1 - Using the object's internal fields. Think of this as
+        //     adding a field to the struct. It's fast, but the space is reserved
+        //     upfront for _every_ instance, whether we use it or not.
+        //
+        // 2 - Using the object's private state with a v8::Private key. Think of
+        //     this as a HashMap. It takes no memory if the cache isn't used
+        //     but has overhead when used.
+        //
+        // Consider `window.document`, (1) we have relatively few Window objects,
+        // (2) They all have a document and (3) The document is accessed _a lot_.
+        // An internal field makes sense.
+        //
+        // Consider `node.childNodes`, (1) we can have 20K+ node objects, (2)
+        // 95% of nodes will never have their .childNodes access by JavaScript.
+        // Private map lookup makes sense.
+        pub const Caching = union(enum) {
+            internal: u8,
+            private: []const u8,
+        };
+    };
+
+    pub fn call(comptime T: type, info_handle: *const v8.FunctionCallbackInfo, func: anytype, comptime opts: Opts) void {
+        const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(info_handle).?;
+        const v8_context = v8.v8__Isolate__GetCurrentContext(v8_isolate).?;
+
+        const ctx = Context.fromC(v8_context);
+        const info = FunctionCallbackInfo{ .handle = info_handle };
+
+        var hs: js.HandleScope = undefined;
+        hs.initWithIsolateHandle(v8_isolate);
+        defer hs.deinit();
+
+        var cache_state: CacheState = undefined;
+        if (comptime opts.cache) |cache| {
+            // This API is a bit weird. On
+            if (respondFromCache(cache, ctx, v8_context, info, &cache_state)) {
+                // Value was fetched from the cache and returned already
+                return;
+            } else {
+                // Cache miss: cache_state will have been populated
+            }
+        }
+
+        var caller: Caller = undefined;
+        caller.initWithContext(ctx, v8_context);
+        defer caller.deinit();
+
+        const js_value = _call(T, &caller.local, info, func, opts) catch |err| {
+            handleError(T, @TypeOf(func), &caller.local, err, info, .{
+                .dom_exception = opts.dom_exception,
+                .as_typed_array = opts.as_typed_array,
+                .null_as_undefined = opts.null_as_undefined,
+            });
+            return;
+        };
+
+        if (comptime opts.cache) |cache| {
+            cache_state.save(cache, js_value);
+        }
+    }
+
+    fn _call(comptime T: type, local: *const Local, info: FunctionCallbackInfo, func: anytype, comptime opts: Opts) !js.Value {
+        const F = @TypeOf(func);
+        var args: ParameterTypes(F) = undefined;
+        if (comptime opts.static) {
+            args = try getArgs(F, 0, local, info);
+        } else {
+            args = try getArgs(F, 1, local, info);
+            @field(args, "0") = try TaggedOpaque.fromJS(*T, info.getThis());
+        }
+        const res = @call(.auto, func, args);
+        const js_value = try local.zigValueToJs(res, .{
+            .dom_exception = opts.dom_exception,
+            .as_typed_array = opts.as_typed_array,
+            .null_as_undefined = opts.null_as_undefined,
+        });
+        info.getReturnValue().set(js_value);
+        return js_value;
+    }
+
+    // We can cache a value directly into the v8::Object so that our callback to fetch a property
+    // can be fast. Generally, think of it like this:
+    //   fn callback(handle: *const v8.FunctionCallbackInfo) callconv(.c) void {
+    //       const js_obj = info.getThis();
+    //       const cached_value = js_obj.getFromCache("Nodes.childNodes");
+    //       info.returnValue().set(cached_value);
+    //   }
+    //
+    // That above pseudocode snippet is largely what this respondFromCache is doing.
+    // But on miss, it's also setting the `cache_state` with all of the data it
+    // got checking the cache, so that, once we get the value from our Zig code,
+    // it's quick to store in the v8::Object for subsequent calls.
+    fn respondFromCache(comptime cache: Opts.Caching, ctx: *Context, v8_context: *const v8.Context, info: FunctionCallbackInfo, cache_state: *CacheState) bool {
+        const js_this = info.getThis();
+        const return_value = info.getReturnValue();
+
+        switch (cache) {
+            .internal => |idx| {
+                if (v8.v8__Object__GetInternalField(js_this, idx)) |cached| {
+                    // means we can't cache undefined, since we can't tell the
+                    // difference between "it isn't in the cache" and  "it's
+                    // in the cache with a valud of undefined"
+                    if (!v8.v8__Value__IsUndefined(cached)) {
+                        return_value.set(cached);
+                        return true;
+                    }
+                }
+
+                // store this so that we can quickly save the result into the cache
+                cache_state.* = .{
+                    .js_this = js_this,
+                    .v8_context = v8_context,
+                    .mode = .{ .internal = idx },
+                };
+            },
+            .private => |private_symbol| {
+                const global_handle = &@field(ctx.env.private_symbols, private_symbol).handle;
+                const private_key: *const v8.Private = v8.v8__Global__Get(global_handle, ctx.isolate.handle).?;
+                if (v8.v8__Object__GetPrivate(js_this, v8_context, private_key)) |cached| {
+                    // This means we can't cache "undefined", since we can't tell
+                    // the difference between a (a) undefined == not in the cache
+                    // and (b) undefined == the cache value.  If this becomes
+                    // important, we can check HasPrivate first. But that requires
+                    // calling HasPrivate then GetPrivate.
+                    if (!v8.v8__Value__IsUndefined(cached)) {
+                        return_value.set(cached);
+                        return true;
+                    }
+                }
+
+                // store this so that we can quickly save the result into the cache
+                cache_state.* = .{
+                    .js_this = js_this,
+                    .v8_context = v8_context,
+                    .mode = .{ .private = private_key },
+                };
+            },
+        }
+
+        // cache miss
+        return false;
+    }
+
+    const CacheState = struct {
+        js_this: *const v8.Object,
+        v8_context: *const v8.Context,
+        mode: union(enum) {
+            internal: u8,
+            private: *const v8.Private,
+        },
+
+        pub fn save(self: *const CacheState, comptime cache: Opts.Caching, js_value: js.Value) void {
+            if (comptime cache == .internal) {
+                v8.v8__Object__SetInternalField(self.js_this, self.mode.internal, js_value.handle);
+            } else {
+                var out: v8.MaybeBool = undefined;
+                v8.v8__Object__SetPrivate(self.js_this, self.v8_context, self.mode.private, js_value.handle, &out);
+            }
+        }
+    };
+};
+
+// If we call a method in javascript: cat.lives('nine');
+//
+// Then we'd expect a Zig function with 2 parameters: a self and the string.
+// In this case, offset == 1. Offset is always 1 for setters or methods.
+//
+// Offset is always 0 for constructors.
+//
+// For constructors, setters and methods, we can further increase offset + 1
+// if the first parameter is an instance of Page.
+//
+// Finally, if the JS function is called with _more_ parameters and
+// the last parameter in Zig is an array, we'll try to slurp the additional
+// parameters into the array.
+fn getArgs(comptime F: type, comptime offset: usize, local: *const Local, info: FunctionCallbackInfo) !ParameterTypes(F) {
+    var args: ParameterTypes(F) = undefined;
+
+    const params = @typeInfo(F).@"fn".params[offset..];
+    // Except for the constructor, the first parameter is always `self`
+    // This isn't something we'll bind from JS, so skip it.
+    const params_to_map = blk: {
+        if (params.len == 0) {
+            return args;
+        }
+
+        // If the last parameter is the Page, set it, and exclude it
+        // from our params slice, because we don't want to bind it to
+        // a JS argument
+        if (comptime isPage(params[params.len - 1].type.?)) {
+            @field(args, tupleFieldName(params.len - 1 + offset)) = local.ctx.page;
+            break :blk params[0 .. params.len - 1];
+        }
+
+        // we have neither a Page nor a JsObject. All params must be
+        // bound to a JavaScript value.
+        break :blk params;
+    };
+
+    if (params_to_map.len == 0) {
+        return args;
+    }
+
+    const js_parameter_count = info.length();
+    const last_js_parameter = params_to_map.len - 1;
+    var is_variadic = false;
+
+    {
+        // This is going to get complicated. If the last Zig parameter
+        // is a slice AND the corresponding javascript parameter is
+        // NOT an an array, then we'll treat it as a variadic.
+
+        const last_parameter_type = params_to_map[params_to_map.len - 1].type.?;
+        const last_parameter_type_info = @typeInfo(last_parameter_type);
+        if (last_parameter_type_info == .pointer and last_parameter_type_info.pointer.size == .slice) {
+            const slice_type = last_parameter_type_info.pointer.child;
+            const corresponding_js_value = info.getArg(@intCast(last_js_parameter), local);
+            if (corresponding_js_value.isArray() == false and corresponding_js_value.isTypedArray() == false and slice_type != u8) {
+                is_variadic = true;
+                if (js_parameter_count == 0) {
+                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = &.{};
+                } else if (js_parameter_count >= params_to_map.len) {
+                    const arr = try local.call_arena.alloc(last_parameter_type_info.pointer.child, js_parameter_count - params_to_map.len + 1);
+                    for (arr, last_js_parameter..) |*a, i| {
+                        a.* = try local.jsValueToZig(slice_type, info.getArg(@intCast(i), local));
+                    }
+                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = arr;
+                } else {
+                    @field(args, tupleFieldName(params_to_map.len + offset - 1)) = &.{};
+                }
+            }
+        }
+    }
+
+    inline for (params_to_map, 0..) |param, i| {
+        const field_index = comptime i + offset;
+        if (comptime i == params_to_map.len - 1) {
+            if (is_variadic) {
+                break;
+            }
+        }
+
+        if (comptime isPage(param.type.?)) {
+            @compileError("Page must be the last parameter (or 2nd last if there's a JsThis): " ++ @typeName(F));
+        } else if (i >= js_parameter_count) {
+            if (@typeInfo(param.type.?) != .optional) {
+                return error.InvalidArgument;
+            }
+            @field(args, tupleFieldName(field_index)) = null;
+        } else {
+            const js_val = info.getArg(@intCast(i), local);
+            @field(args, tupleFieldName(field_index)) = local.jsValueToZig(param.type.?, js_val) catch {
+                return error.InvalidArgument;
+            };
+        }
+    }
+
+    return args;
+}

src/browser/js/Context.zig

@@ -21,8 +21,9 @@ const lp = @import("lightpanda");
 const log = @import("../../log.zig");
 
 const js = @import("js.zig");
+const Env = @import("Env.zig");
 const bridge = @import("bridge.zig");
-const TaggedOpaque = @import("TaggedOpaque.zig");
+const Scheduler = @import("Scheduler.zig");
 
 const Page = @import("../Page.zig");
 const ScriptManager = @import("../ScriptManager.zig");
@@ -38,6 +39,7 @@ const IS_DEBUG = @import("builtin").mode == .Debug;
 const Context = @This();
 
 id: usize,
+env: *Env,
 page: *Page,
 isolate: js.Isolate,
 
@@ -82,7 +84,8 @@ identity_map: std.AutoHashMapUnmanaged(usize, v8.Global) = .empty,
 // Any type that is stored in the identity_map which has a finalizer declared
 // will have its finalizer stored here. This is only used when shutting down
 // if v8 hasn't called the finalizer directly itself.
-finalizer_callbacks: std.AutoHashMapUnmanaged(usize, FinalizerCallback) = .empty,
+finalizer_callbacks: std.AutoHashMapUnmanaged(usize, *FinalizerCallback) = .empty,
+finalizer_callback_pool: std.heap.MemoryPool(FinalizerCallback),
 
 // Some web APIs have to manage opaque values. Ideally, they use an
 // js.Object, but the js.Object has no lifetime guarantee beyond the
@@ -102,6 +105,7 @@ global_promise_resolvers: std.ArrayList(v8.Global) = .empty,
 // Temp variants stored in HashMaps for O(1) early cleanup.
 // Key is global.data_ptr.
 global_values_temp: std.AutoHashMapUnmanaged(usize, v8.Global) = .empty,
+global_promises_temp: std.AutoHashMapUnmanaged(usize, v8.Global) = .empty,
 global_functions_temp: std.AutoHashMapUnmanaged(usize, v8.Global) = .empty,
 
 // Our module cache: normalized module specifier => module.
@@ -117,6 +121,15 @@ module_identifier: std.AutoHashMapUnmanaged(u32, [:0]const u8) = .empty,
 // the page's script manager
 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 {
     // Can be null if we're asynchrously loading the module, in
     // which case resolver_promise cannot be null.
@@ -135,7 +148,7 @@ const ModuleEntry = struct {
     resolver_promise: ?js.Promise.Global = null,
 };
 
-fn fromC(c_context: *const v8.Context) *Context {
+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());
@@ -149,6 +162,33 @@ pub fn fromIsolate(isolate: js.Isolate) *Context {
 }
 
 pub fn deinit(self: *Context) void {
+    if (comptime IS_DEBUG) {
+        var it = self.unknown_properties.iterator();
+        while (it.next()) |kv| {
+            log.debug(.unknown_prop, "unknown property", .{
+                .property = kv.key_ptr.*,
+                .occurrences = kv.value_ptr.count,
+                .first_stack = kv.value_ptr.first_stack,
+            });
+        }
+    }
+    defer self.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
+    self.scheduler.deinit();
+
     {
         var it = self.identity_map.valueIterator();
         while (it.next()) |global| {
@@ -158,8 +198,9 @@ pub fn deinit(self: *Context) void {
     {
         var it = self.finalizer_callbacks.valueIterator();
         while (it.next()) |finalizer| {
-            finalizer.deinit();
+            finalizer.*.deinit();
         }
+        self.finalizer_callback_pool.deinit();
     }
 
     for (self.global_values.items) |*global| {
@@ -193,6 +234,13 @@ pub fn deinit(self: *Context) void {
         }
     }
 
+    {
+        var it = self.global_promises_temp.valueIterator();
+        while (it.next()) |global| {
+            v8.v8__Global__Reset(global);
+        }
+    }
+
     {
         var it = self.global_functions_temp.valueIterator();
         while (it.next()) |global| {
@@ -201,34 +249,44 @@ pub fn deinit(self: *Context) void {
     }
 
     if (self.entered) {
-        var ls: js.Local.Scope = undefined;
-        self.localScope(&ls);
-        defer ls.deinit();
-        v8.v8__Context__Exit(ls.local.handle);
+        v8.v8__Context__Exit(@ptrCast(v8.v8__Global__Get(&self.handle, self.isolate.handle)));
     }
+
     v8.v8__Global__Reset(&self.handle);
 }
 
 pub fn weakRef(self: *Context, obj: anytype) void {
-    const global = self.identity_map.getPtr(@intFromPtr(obj)) orelse {
+    const fc = self.finalizer_callbacks.get(@intFromPtr(obj)) orelse {
         if (comptime IS_DEBUG) {
             // should not be possible
             std.debug.assert(false);
         }
         return;
     };
-    v8.v8__Global__SetWeakFinalizer(global, obj, bridge.Struct(@TypeOf(obj)).JsApi.Meta.finalizer.from_v8, v8.kParameter);
+    v8.v8__Global__SetWeakFinalizer(&fc.global, fc, bridge.Struct(@TypeOf(obj)).JsApi.Meta.finalizer.from_v8, v8.kParameter);
+}
+
+pub fn safeWeakRef(self: *Context, obj: anytype) void {
+    const fc = self.finalizer_callbacks.get(@intFromPtr(obj)) orelse {
+        if (comptime IS_DEBUG) {
+            // should not be possible
+            std.debug.assert(false);
+        }
+        return;
+    };
+    v8.v8__Global__ClearWeak(&fc.global);
+    v8.v8__Global__SetWeakFinalizer(&fc.global, fc, bridge.Struct(@TypeOf(obj)).JsApi.Meta.finalizer.from_v8, v8.kParameter);
 }
 
 pub fn strongRef(self: *Context, obj: anytype) void {
-    const global = self.identity_map.getPtr(@intFromPtr(obj)) orelse {
+    const fc = self.finalizer_callbacks.get(@intFromPtr(obj)) orelse {
         if (comptime IS_DEBUG) {
             // should not be possible
             std.debug.assert(false);
         }
         return;
     };
-    v8.v8__Global__ClearWeak(global);
+    v8.v8__Global__ClearWeak(&fc.global);
 }
 
 pub fn release(self: *Context, item: anytype) void {
@@ -246,17 +304,20 @@ pub fn release(self: *Context, item: anytype) void {
 
         // The item has been fianalized, remove it for the finalizer callback so that
         // we don't try to call it again on shutdown.
-        _ = self.finalizer_callbacks.fetchRemove(@intFromPtr(item)) orelse {
+        const fc = self.finalizer_callbacks.fetchRemove(@intFromPtr(item)) orelse {
             if (comptime IS_DEBUG) {
                 // should not be possible
                 std.debug.assert(false);
             }
+            return;
         };
+        self.finalizer_callback_pool.destroy(fc.value);
         return;
     }
 
     var map = switch (@TypeOf(item)) {
         js.Value.Temp => &self.global_values_temp,
+        js.Promise.Temp => &self.global_promises_temp,
         js.Function.Temp => &self.global_functions_temp,
         else => |T| @compileError("Context.release cannot be called with a " ++ @typeName(T)),
     };
@@ -320,7 +381,25 @@ pub fn module(self: *Context, comptime want_result: bool, local: *const js.Local
         if (cacheable) {
             gop = try self.module_cache.getOrPut(arena, url);
             if (gop.found_existing) {
-                if (gop.value_ptr.module != null) {
+                if (gop.value_ptr.module) |cache_mod| {
+                    if (gop.value_ptr.module_promise == null) {
+                        // This an usual case, but it can happen if a module is
+                        // first asynchronously requested and then synchronously
+                        // requested as a child of some root import. In that case,
+                        // the module may not be instantiated yet (so we have to
+                        // do that). It might not be evaluated yet. So we have
+                        // to do that too. Evaluation is particularly important
+                        // as it sets up our cache entry's module_promise.
+                        // It appears that v8 handles potential double-instantiated
+                        // and double-evaluated modules safely. The 2nd instantiation
+                        // is a no-op, and the second evaluation returns the same
+                        // promise.
+                        const mod = local.toLocal(cache_mod);
+                        if (mod.getStatus() == .kUninstantiated and try mod.instantiate(resolveModuleCallback) == false) {
+                            return error.ModuleInstantiationError;
+                        }
+                        return self.evaluateModule(want_result, mod, url, true);
+                    }
                     return if (comptime want_result) gop.value_ptr.* else {};
                 }
             } else {
@@ -350,6 +429,10 @@ pub fn module(self: *Context, comptime want_result: bool, local: *const js.Local
         return error.ModuleInstantiationError;
     }
 
+    return self.evaluateModule(want_result, mod, owned_url, cacheable);
+}
+
+fn evaluateModule(self: *Context, comptime want_result: bool, mod: js.Module, url: []const u8, cacheable: bool) !(if (want_result) ModuleEntry else void) {
     const evaluated = mod.evaluate() catch {
         if (comptime IS_DEBUG) {
             std.debug.assert(mod.getStatus() == .kErrored);
@@ -357,9 +440,13 @@ pub fn module(self: *Context, comptime want_result: bool, local: *const js.Local
 
         // Some module-loading errors aren't handled by TryCatch. We need to
         // get the error from the module itself.
+        const message = blk: {
+            const e = mod.getException().toString() catch break :blk "???";
+            break :blk e.toSlice() catch "???";
+        };
         log.warn(.js, "evaluate module", .{
-            .specifier = owned_url,
-            .message = mod.getException().toString(.{}) catch "???",
+            .message = message,
+            .specifier = url,
         });
         return error.EvaluationError;
     };
@@ -368,24 +455,15 @@ pub fn module(self: *Context, comptime want_result: bool, local: *const js.Local
     // Must be a promise that gets returned here.
     lp.assert(evaluated.isPromise(), "Context.module non-promise", .{});
 
-    if (comptime !want_result) {
-        // avoid creating a bunch of persisted objects if it isn't
-        // cacheable and the caller doesn't care about results.
-        // This is pretty common, i.e. every <script type=module>
-        // within the html page.
-        if (!cacheable) {
-            return;
+    if (!cacheable) {
+        switch (comptime want_result) {
+            false => return,
+            true => unreachable,
         }
     }
 
-    // anyone who cares about the result, should also want it to
-    // be cached
-    if (comptime IS_DEBUG) {
-        std.debug.assert(cacheable);
-    }
-
     // entry has to have been created atop this function
-    const entry = self.module_cache.getPtr(owned_url).?;
+    const entry = self.module_cache.getPtr(url).?;
 
     // and the module must have been set after we compiled it
     lp.assert(entry.module != null, "Context.module with module", .{});
@@ -457,11 +535,11 @@ fn postCompileModule(self: *Context, mod: js.Module, url: [:0]const u8, local: *
     const request_len = requests.len();
     const script_manager = self.script_manager.?;
     for (0..request_len) |i| {
-        const specifier = try local.jsStringToZigZ(requests.get(i).specifier(), .{});
+        const specifier = requests.get(i).specifier(local);
         const normalized_specifier = try script_manager.resolveSpecifier(
             self.call_arena,
             url,
-            specifier,
+            try specifier.toSliceZ(),
         );
         const nested_gop = try self.module_cache.getOrPut(self.arena, normalized_specifier);
         if (!nested_gop.found_existing) {
@@ -494,14 +572,14 @@ fn resolveModuleCallback(
     _ = import_attributes;
 
     const self = fromC(c_context.?);
-    var local = js.Local{
+    const local = js.Local{
         .ctx = self,
         .handle = c_context.?,
         .isolate = self.isolate,
         .call_arena = self.call_arena,
     };
 
-    const specifier = local.jsStringToZigZ(c_specifier.?, .{}) catch |err| {
+    const specifier = js.String.toSliceZ(.{ .local = &local, .handle = c_specifier.? }) catch |err| {
         log.err(.js, "resolve module", .{ .err = err });
         return null;
     };
@@ -527,19 +605,19 @@ pub fn dynamicModuleCallback(
     _ = import_attrs;
 
     const self = fromC(c_context.?);
-    var local = js.Local{
+    const local = js.Local{
         .ctx = self,
         .handle = c_context.?,
         .call_arena = self.call_arena,
         .isolate = self.isolate,
     };
 
-    const resource = local.jsStringToZigZ(resource_name.?, .{}) catch |err| {
+    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 specifier = local.jsStringToZigZ(v8_specifier.?, .{}) catch |err| {
+    const specifier = js.String.toSliceZ(.{ .local = &local, .handle = v8_specifier.? }) catch |err| {
         log.err(.app, "OOM", .{ .err = err, .src = "dynamicModuleCallback2" });
         return @constCast((local.rejectPromise("Out of memory") catch return null).handle);
     };
@@ -684,6 +762,9 @@ fn _dynamicModuleCallback(self: *Context, specifier: [:0]const u8, referrer: []c
         return promise;
     }
 
+    // we might update the map, so we might need to re-fetch this.
+    var entry = gop.value_ptr;
+
     // So we have a module, but no async resolver. This can only
     // happen if the module was first synchronously loaded (Does that
     // ever even happen?!) You'd think we can just return the module
@@ -696,7 +777,7 @@ fn _dynamicModuleCallback(self: *Context, specifier: [:0]const u8, referrer: []c
 
     // If the module hasn't been evaluated yet (it was only instantiated
     // as a static import dependency), we need to evaluate it now.
-    if (gop.value_ptr.module_promise == null) {
+    if (entry.module_promise == null) {
         const mod = local.toLocal(gop.value_ptr.module.?);
         const status = mod.getStatus();
         if (status == .kEvaluated or status == .kEvaluating) {
@@ -705,7 +786,7 @@ fn _dynamicModuleCallback(self: *Context, specifier: [:0]const u8, referrer: []c
             const module_resolver = local.createPromiseResolver();
             module_resolver.resolve("resolve module", mod.getModuleNamespace());
             _ = try module_resolver.persist();
-            gop.value_ptr.module_promise = try module_resolver.promise().persist();
+            entry.module_promise = try module_resolver.promise().persist();
         } else {
             // the module was loaded, but not evaluated, we _have_ to evaluate it now
             const evaluated = mod.evaluate() catch {
@@ -716,18 +797,20 @@ fn _dynamicModuleCallback(self: *Context, specifier: [:0]const u8, referrer: []c
                 return promise;
             };
             lp.assert(evaluated.isPromise(), "Context._dynamicModuleCallback non-promise", .{});
-            gop.value_ptr.module_promise = try evaluated.toPromise().persist();
+            // mod.evaluate can invalidate or gop
+            entry = self.module_cache.getPtr(specifier).?;
+            entry.module_promise = try evaluated.toPromise().persist();
         }
     }
 
     // like before, we want to set this up so that if anything else
     // tries to load this module, it can just return our promise
     // since we're going to be doing all the work.
-    gop.value_ptr.resolver_promise = try promise.persist();
+    entry.resolver_promise = try promise.persist();
 
     // But we can skip direclty to `resolveDynamicModule` which is
     // what the above callback will eventually do.
-    self.resolveDynamicModule(state, gop.value_ptr.*, local);
+    self.resolveDynamicModule(state, entry.*, local);
     return promise;
 }
 
@@ -844,70 +927,121 @@ fn resolveDynamicModule(self: *Context, state: *DynamicModuleResolveState, modul
     };
 }
 
-// Microtasks
+// Used to make temporarily enter and exit a context, updating and restoring
+// page.js:
+//    var hs: js.HandleScope = undefined;
+//    const entered = ctx.enter(&hs);
+//    defer entered.exit();
+pub fn enter(self: *Context, hs: *js.HandleScope) Entered {
+    const isolate = self.isolate;
+    js.HandleScope.init(hs, isolate);
+
+    const page = self.page;
+    const original = page.js;
+    page.js = self;
+
+    const handle: *const v8.Context = @ptrCast(v8.v8__Global__Get(&self.handle, isolate.handle));
+    v8.v8__Context__Enter(handle);
+    return .{ .original = original, .handle = handle, .handle_scope = hs };
+}
+
+const Entered = struct {
+    // the context we should restore on the page
+    original: *Context,
+
+    // the handle of the entered context
+    handle: *const v8.Context,
+
+    handle_scope: *js.HandleScope,
+
+    pub fn exit(self: Entered) void {
+        self.original.page.js = self.original;
+        v8.v8__Context__Exit(self.handle);
+        self.handle_scope.deinit();
+    }
+};
+
 pub fn queueMutationDelivery(self: *Context) !void {
-    self.isolate.enqueueMicrotask(struct {
-        fn run(data: ?*anyopaque) callconv(.c) void {
-            const page: *Page = @ptrCast(@alignCast(data.?));
-            page.deliverMutations();
+    self.enqueueMicrotask(struct {
+        fn run(ctx: *Context) void {
+            ctx.page.deliverMutations();
         }
-    }.run, self.page);
+    }.run);
 }
 
 pub fn queueIntersectionChecks(self: *Context) !void {
-    self.isolate.enqueueMicrotask(struct {
-        fn run(data: ?*anyopaque) callconv(.c) void {
-            const page: *Page = @ptrCast(@alignCast(data.?));
-            page.performScheduledIntersectionChecks();
+    self.enqueueMicrotask(struct {
+        fn run(ctx: *Context) void {
+            ctx.page.performScheduledIntersectionChecks();
         }
-    }.run, self.page);
+    }.run);
 }
 
 pub fn queueIntersectionDelivery(self: *Context) !void {
-    self.isolate.enqueueMicrotask(struct {
-        fn run(data: ?*anyopaque) callconv(.c) void {
-            const page: *Page = @ptrCast(@alignCast(data.?));
-            page.deliverIntersections();
+    self.enqueueMicrotask(struct {
+        fn run(ctx: *Context) void {
+            ctx.page.deliverIntersections();
         }
-    }.run, self.page);
+    }.run);
 }
 
 pub fn queueSlotchangeDelivery(self: *Context) !void {
+    self.enqueueMicrotask(struct {
+        fn run(ctx: *Context) void {
+            ctx.page.deliverSlotchangeEvents();
+        }
+    }.run);
+}
+
+// Helper for executing a Microtask on this Context. In V8, microtasks aren't
+// associated to a Context - they are just functions to execute in an Isolate.
+// 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 {
         fn run(data: ?*anyopaque) callconv(.c) void {
-            const page: *Page = @ptrCast(@alignCast(data.?));
-            page.deliverSlotchangeEvents();
+            const ctx: *Context = @ptrCast(@alignCast(data.?));
+            if (ctx.shutting_down) {
+                return;
+            }
+
+            var hs: js.HandleScope = undefined;
+            const entered = ctx.enter(&hs);
+            defer entered.exit();
+            callback(ctx);
         }
-    }.run, self.page);
+    }.run, self);
 }
 
 pub fn queueMicrotaskFunc(self: *Context, cb: js.Function) void {
     self.isolate.enqueueMicrotaskFunc(cb);
 }
 
+pub fn createFinalizerCallback(self: *Context, global: v8.Global, ptr: *anyopaque, finalizerFn: *const fn (ptr: *anyopaque) void) !*FinalizerCallback {
+    const fc = try self.finalizer_callback_pool.create();
+    fc.* = .{
+        .ctx = self,
+        .ptr = ptr,
+        .global = global,
+        .finalizerFn = finalizerFn,
+    };
+    return fc;
+}
+
 // == Misc ==
 // A type that has a finalizer can have its finalizer called one of two ways.
 // The first is from V8 via the WeakCallback we give to weakRef. But that isn't
 // guaranteed to fire, so we track this in ctx._finalizers and call them on
 // context shutdown.
-const FinalizerCallback = struct {
+pub const FinalizerCallback = struct {
+    ctx: *Context,
     ptr: *anyopaque,
+    global: v8.Global,
     finalizerFn: *const fn (ptr: *anyopaque) void,
 
-    pub fn init(ptr: anytype) FinalizerCallback {
-        const T = bridge.Struct(@TypeOf(ptr));
-        return .{
-            .ptr = ptr,
-            .finalizerFn = struct {
-                pub fn wrap(self: *anyopaque) void {
-                    T.JsApi.Meta.finalizer.from_zig(self);
-                }
-            }.wrap,
-        };
-    }
-
-    pub fn deinit(self: FinalizerCallback) void {
+    pub fn deinit(self: *FinalizerCallback) void {
         self.finalizerFn(self.ptr);
+        self.ctx.finalizer_callback_pool.destroy(self);
     }
 };
 
@@ -940,7 +1074,7 @@ pub fn stopCpuProfiler(self: *Context) ![]const u8 {
     const title = self.isolate.initStringHandle("v8_cpu_profile");
     const handle = v8.v8__CpuProfiler__StopProfiling(self.cpu_profiler.?, title) orelse return error.NoProfiles;
     const string_handle = v8.v8__CpuProfile__Serialize(handle, self.isolate.handle) orelse return error.NoProfile;
-    return ls.local.jsStringToZig(string_handle, .{});
+    return (js.String{ .local = &ls.local, .handle = string_handle }).toSlice();
 }
 
 pub fn startHeapProfiler(self: *Context) void {
@@ -972,7 +1106,7 @@ pub fn stopHeapProfiler(self: *Context) !struct { []const u8, []const u8 } {
         const string_handle = v8.v8__AllocationProfile__Serialize(profile, self.isolate.handle);
         v8.v8__HeapProfiler__StopSamplingHeapProfiler(self.heap_profiler.?);
         v8.v8__AllocationProfile__Delete(profile);
-        break :blk try ls.local.jsStringToZig(string_handle, .{});
+        break :blk try (js.String{ .local = &ls.local, .handle = string_handle.? }).toSlice();
     };
 
     const snapshot = blk: {
@@ -980,8 +1114,13 @@ pub fn stopHeapProfiler(self: *Context) !struct { []const u8, []const u8 } {
         const string_handle = v8.v8__HeapSnapshot__Serialize(snapshot, self.isolate.handle);
         v8.v8__HeapProfiler__StopTrackingHeapObjects(self.heap_profiler.?);
         v8.v8__HeapSnapshot__Delete(snapshot);
-        break :blk try ls.local.jsStringToZig(string_handle, .{});
+        break :blk try (js.String{ .local = &ls.local, .handle = string_handle.? }).toSlice();
     };
 
     return .{ allocating, snapshot };
 }
+
+const UnknownPropertyStat = struct {
+    count: usize,
+    first_stack: []const u8,
+};

src/browser/js/Env.zig

@@ -18,8 +18,11 @@
 
 const std = @import("std");
 const js = @import("js.zig");
+const builtin = @import("builtin");
+
 const v8 = js.v8;
 
+const App = @import("../../App.zig");
 const log = @import("../../log.zig");
 
 const bridge = @import("bridge.zig");
@@ -28,13 +31,21 @@ const Isolate = @import("Isolate.zig");
 const Platform = @import("Platform.zig");
 const Snapshot = @import("Snapshot.zig");
 const Inspector = @import("Inspector.zig");
-const ExecutionWorld = @import("ExecutionWorld.zig");
 
+const Page = @import("../Page.zig");
 const Window = @import("../webapi/Window.zig");
 
 const JsApis = bridge.JsApis;
 const Allocator = std.mem.Allocator;
-const ArenaAllocator = std.heap.ArenaAllocator;
+const IS_DEBUG = builtin.mode == .Debug;
+
+fn initClassIds() void {
+    inline for (JsApis, 0..) |JsApi, i| {
+        JsApi.Meta.class_id = i;
+    }
+}
+
+var class_id_once = std.once(initClassIds);
 
 // The Env maps to a V8 isolate, which represents a isolated sandbox for
 // executing JavaScript. The Env is where we'll define our V8 <-> Zig bindings,
@@ -44,13 +55,15 @@ const ArenaAllocator = std.heap.ArenaAllocator;
 // The `types` parameter is a tuple of Zig structures we want to bind to V8.
 const Env = @This();
 
-allocator: Allocator,
+app: *App,
 
 platform: *const Platform,
 
 // the global isolate
 isolate: js.Isolate,
 
+contexts: std.ArrayList(*js.Context),
+
 // just kept around because we need to free it on deinit
 isolate_params: *v8.CreateParams,
 
@@ -65,7 +78,32 @@ templates: []*const v8.FunctionTemplate,
 // Global template created once per isolate and reused across all contexts
 global_template: v8.Eternal,
 
-pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot) !Env {
+// Inspector associated with the Isolate. Exists when CDP is being used.
+inspector: ?*Inspector,
+
+// We can store data in a v8::Object's Private data bag. The keys are v8::Private
+// which an be created once per isolaet.
+private_symbols: PrivateSymbols,
+
+pub const InitOpts = struct {
+    with_inspector: bool = false,
+};
+
+pub fn init(app: *App, opts: InitOpts) !Env {
+    if (comptime IS_DEBUG) {
+        comptime {
+            // V8 requirement for any data using SetAlignedPointerInInternalField
+            const a = @alignOf(@import("TaggedOpaque.zig"));
+            std.debug.assert(a >= 2 and a % 2 == 0);
+        }
+    }
+
+    // Initialize class IDs once before any V8 work
+    class_id_once.call();
+
+    const allocator = app.allocator;
+    const snapshot = &app.snapshot;
+
     var params = try allocator.create(v8.CreateParams);
     errdefer allocator.destroy(params);
     v8.v8__Isolate__CreateParams__CONSTRUCT(params);
@@ -78,17 +116,18 @@ pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot
 
     var isolate = js.Isolate.init(params);
     errdefer isolate.deinit();
+    const isolate_handle = isolate.handle;
 
-    v8.v8__Isolate__SetHostImportModuleDynamicallyCallback(isolate.handle, Context.dynamicModuleCallback);
-    v8.v8__Isolate__SetPromiseRejectCallback(isolate.handle, promiseRejectCallback);
-    v8.v8__Isolate__SetMicrotasksPolicy(isolate.handle, v8.kExplicit);
-    v8.v8__Isolate__SetFatalErrorHandler(isolate.handle, fatalCallback);
-    v8.v8__Isolate__SetOOMErrorHandler(isolate.handle, oomCallback);
+    v8.v8__Isolate__SetHostImportModuleDynamicallyCallback(isolate_handle, Context.dynamicModuleCallback);
+    v8.v8__Isolate__SetPromiseRejectCallback(isolate_handle, promiseRejectCallback);
+    v8.v8__Isolate__SetMicrotasksPolicy(isolate_handle, v8.kExplicit);
+    v8.v8__Isolate__SetFatalErrorHandler(isolate_handle, fatalCallback);
+    v8.v8__Isolate__SetOOMErrorHandler(isolate_handle, oomCallback);
 
     isolate.enter();
     errdefer isolate.exit();
 
-    v8.v8__Isolate__SetHostInitializeImportMetaObjectCallback(isolate.handle, Context.metaObjectCallback);
+    v8.v8__Isolate__SetHostInitializeImportMetaObjectCallback(isolate_handle, Context.metaObjectCallback);
 
     // Allocate arrays dynamically to avoid comptime dependency on JsApis.len
     const eternal_function_templates = try allocator.alloc(v8.Eternal, JsApis.len);
@@ -98,26 +137,26 @@ pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot
     errdefer allocator.free(templates);
 
     var global_eternal: v8.Eternal = undefined;
+    var private_symbols: PrivateSymbols = undefined;
     {
         var temp_scope: js.HandleScope = undefined;
         temp_scope.init(isolate);
         defer temp_scope.deinit();
 
-        inline for (JsApis, 0..) |JsApi, i| {
-            JsApi.Meta.class_id = i;
-            const data = v8.v8__Isolate__GetDataFromSnapshotOnce(isolate.handle, snapshot.data_start + i);
+        inline for (JsApis, 0..) |_, i| {
+            const data = v8.v8__Isolate__GetDataFromSnapshotOnce(isolate_handle, snapshot.data_start + i);
             const function_handle: *const v8.FunctionTemplate = @ptrCast(data);
             // Make function template eternal
-            v8.v8__Eternal__New(isolate.handle, @ptrCast(function_handle), &eternal_function_templates[i]);
+            v8.v8__Eternal__New(isolate_handle, @ptrCast(function_handle), &eternal_function_templates[i]);
 
             // Extract the local handle from the global for easy access
-            const eternal_ptr = v8.v8__Eternal__Get(&eternal_function_templates[i], isolate.handle);
+            const eternal_ptr = v8.v8__Eternal__Get(&eternal_function_templates[i], isolate_handle);
             templates[i] = @ptrCast(@alignCast(eternal_ptr.?));
         }
 
         // Create global template once per isolate
-        const js_global = v8.v8__FunctionTemplate__New__DEFAULT(isolate.handle);
-        const window_name = v8.v8__String__NewFromUtf8(isolate.handle, "Window", v8.kNormal, 6);
+        const js_global = v8.v8__FunctionTemplate__New__DEFAULT(isolate_handle);
+        const window_name = v8.v8__String__NewFromUtf8(isolate_handle, "Window", v8.kNormal, 6);
         v8.v8__FunctionTemplate__SetClassName(js_global, window_name);
 
         // Find Window in JsApis by name (avoids circular import)
@@ -126,7 +165,7 @@ pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot
 
         const global_template_local = v8.v8__FunctionTemplate__InstanceTemplate(js_global).?;
         v8.v8__ObjectTemplate__SetNamedHandler(global_template_local, &.{
-            .getter = bridge.unknownPropertyCallback,
+            .getter = bridge.unknownWindowPropertyCallback,
             .setter = null,
             .query = null,
             .deleter = null,
@@ -136,41 +175,184 @@ pub fn init(allocator: Allocator, platform: *const Platform, snapshot: *Snapshot
             .data = null,
             .flags = v8.kOnlyInterceptStrings | v8.kNonMasking,
         });
-        v8.v8__Eternal__New(isolate.handle, @ptrCast(global_template_local), &global_eternal);
+        v8.v8__Eternal__New(isolate_handle, @ptrCast(global_template_local), &global_eternal);
+
+        private_symbols = PrivateSymbols.init(isolate_handle);
+    }
+
+    var inspector: ?*js.Inspector = null;
+    if (opts.with_inspector) {
+        inspector = try Inspector.init(allocator, isolate_handle);
     }
 
     return .{
+        .app = app,
         .context_id = 0,
+        .contexts = .empty,
         .isolate = isolate,
-        .platform = platform,
-        .allocator = allocator,
+        .platform = &app.platform,
         .templates = templates,
         .isolate_params = params,
-        .eternal_function_templates = eternal_function_templates,
+        .inspector = inspector,
         .global_template = global_eternal,
+        .private_symbols = private_symbols,
+        .eternal_function_templates = eternal_function_templates,
     };
 }
 
 pub fn deinit(self: *Env) void {
-    self.allocator.free(self.templates);
-    self.allocator.free(self.eternal_function_templates);
+    if (comptime IS_DEBUG) {
+        std.debug.assert(self.contexts.items.len == 0);
+    }
+    for (self.contexts.items) |ctx| {
+        ctx.deinit();
+    }
+
+    const allocator = self.app.allocator;
+    if (self.inspector) |i| {
+        i.deinit(allocator);
+    }
+
+    self.contexts.deinit(allocator);
+
+    allocator.free(self.templates);
+    allocator.free(self.eternal_function_templates);
+    self.private_symbols.deinit();
 
     self.isolate.exit();
     self.isolate.deinit();
     v8.v8__ArrayBuffer__Allocator__DELETE(self.isolate_params.array_buffer_allocator.?);
-    self.allocator.destroy(self.isolate_params);
+    allocator.destroy(self.isolate_params);
 }
 
-pub fn newInspector(self: *Env, arena: Allocator, ctx: anytype) !*Inspector {
-    const inspector = try arena.create(Inspector);
-    try Inspector.init(inspector, self.isolate.handle, ctx);
-    return inspector;
+pub fn createContext(self: *Env, page: *Page, enter: bool) !*Context {
+    const context_arena = try self.app.arena_pool.acquire();
+    errdefer self.app.arena_pool.release(context_arena);
+
+    const isolate = self.isolate;
+    var hs: js.HandleScope = undefined;
+    hs.init(isolate);
+    defer hs.deinit();
+
+    // 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).?;
+
+    // Create the v8::Context and wrap it in a v8::Global
+    var context_global: v8.Global = undefined;
+    v8.v8__Global__New(isolate.handle, v8_context, &context_global);
+
+    // get the global object for the context, this maps to our Window
+    const global_obj = v8.v8__Context__Global(v8_context).?;
+    {
+        // Store our TAO inside the internal field of the global object. This
+        // maps the v8::Object -> Zig instance. Almost all objects have this, and
+        // it gets setup automatically as objects are created, but the Window
+        // object already exists in v8 (it's the global) so we manually create
+        // the mapping here.
+        const tao = try context_arena.create(@import("TaggedOpaque.zig"));
+        tao.* = .{
+            .value = @ptrCast(page.window),
+            .prototype_chain = (&Window.JsApi.Meta.prototype_chain).ptr,
+            .prototype_len = @intCast(Window.JsApi.Meta.prototype_chain.len),
+            .subtype = .node, // this probably isn't right, but it's what we've been doing all along
+        };
+        v8.v8__Object__SetAlignedPointerInInternalField(global_obj, 0, tao);
+    }
+    // our window wrapped in a v8::Global
+    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;
+
+    const context = try context_arena.create(Context);
+    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,
+        .script_manager = &page._script_manager,
+        .scheduler = .init(context_arena),
+        .finalizer_callback_pool = std.heap.MemoryPool(Context.FinalizerCallback).init(self.app.allocator),
+    };
+    try context.identity_map.putNoClobber(context_arena, @intFromPtr(page.window), global_global);
+
+    // 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));
+
+    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| {
+        if (ctx == context) {
+            _ = self.contexts.swapRemove(i);
+            break;
+        }
+    } else {
+        if (comptime IS_DEBUG) {
+            @panic("Tried to remove unknown context");
+        }
+    }
+
+    const isolate = self.isolate;
+    if (self.inspector) |inspector| {
+        var hs: js.HandleScope = undefined;
+        hs.init(isolate);
+        defer hs.deinit();
+        inspector.contextDestroyed(@ptrCast(v8.v8__Global__Get(&context.handle, isolate.handle)));
+    }
+
+    context.deinit();
+    isolate.notifyContextDisposed();
 }
 
 pub fn runMicrotasks(self: *const Env) void {
     self.isolate.performMicrotasksCheckpoint();
 }
 
+pub fn runMacrotasks(self: *Env) !?u64 {
+    var ms_to_next_task: ?u64 = null;
+    for (self.contexts.items) |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
+            // underterministic whether a timer will or won't run before the
+            // page shutsdown. But for tests, we need to run them to their end.
+            if (ctx.scheduler.hasReadyTasks() == false) {
+                continue;
+            }
+        }
+
+        var hs: js.HandleScope = undefined;
+        const entered = ctx.enter(&hs);
+        defer entered.exit();
+
+        const ms = (try ctx.scheduler.run()) orelse continue;
+        if (ms_to_next_task == null or ms < ms_to_next_task.?) {
+            ms_to_next_task = ms;
+        }
+    }
+    return ms_to_next_task;
+}
+
 pub fn pumpMessageLoop(self: *const Env) bool {
     var hs: v8.HandleScope = undefined;
     v8.v8__HandleScope__CONSTRUCT(&hs, self.isolate.handle);
@@ -182,13 +364,6 @@ pub fn pumpMessageLoop(self: *const Env) bool {
 pub fn runIdleTasks(self: *const Env) void {
     v8.v8__Platform__RunIdleTasks(self.platform.handle, self.isolate.handle, 1);
 }
-pub fn newExecutionWorld(self: *Env) !ExecutionWorld {
-    return .{
-        .env = self,
-        .context = null,
-        .context_arena = ArenaAllocator.init(self.allocator),
-    };
-}
 
 // V8 doesn't immediately free memory associated with
 // a Context, it's managed by the garbage collector. We use the
@@ -252,18 +427,13 @@ fn promiseRejectCallback(message_handle: v8.PromiseRejectMessage) callconv(.c) v
         .call_arena = ctx.call_arena,
     };
 
-    const value =
-        if (v8.v8__PromiseRejectMessage__GetValue(&message_handle)) |v8_value|
-            // @HandleScope - no reason to create a js.Context here
-            local.valueHandleToString(v8_value, .{}) catch |err| @errorName(err)
-        else
-            "no value";
-
-    log.debug(.js, "unhandled rejection", .{
-        .value = value,
-        .stack = local.stackTrace() catch |err| @errorName(err) orelse "???",
-        .note = "This should be updated to call window.unhandledrejection",
-    });
+    const page = ctx.page;
+    page.window.unhandledPromiseRejection(.{
+        .local = &local,
+        .handle = &message_handle,
+    }, page) catch |err| {
+        log.warn(.browser, "unhandled rejection handler", .{ .err = err });
+    };
 }
 
 fn fatalCallback(c_location: [*c]const u8, c_message: [*c]const u8) callconv(.c) void {
@@ -279,3 +449,19 @@ fn oomCallback(c_location: [*c]const u8, details: ?*const v8.OOMDetails) callcon
     log.fatal(.app, "V8 OOM", .{ .location = location, .detail = detail });
     @import("../../crash_handler.zig").crash("V8 OOM", .{ .location = location, .detail = detail }, @returnAddress());
 }
+
+const PrivateSymbols = struct {
+    const Private = @import("Private.zig");
+
+    child_nodes: Private,
+
+    fn init(isolate: *v8.Isolate) PrivateSymbols {
+        return .{
+            .child_nodes = Private.init(isolate, "child_nodes"),
+        };
+    }
+
+    fn deinit(self: *PrivateSymbols) void {
+        self.child_nodes.deinit();
+    }
+};

src/browser/js/ExecutionWorld.zig

@@ -1,136 +0,0 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
-//
-// Francis Bouvier <francis@lightpanda.io>
-// Pierre Tachoire <pierre@lightpanda.io>
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as
-// published by the Free Software Foundation, either version 3 of the
-// License, or (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-const std = @import("std");
-const lp = @import("lightpanda");
-
-const log = @import("../../log.zig");
-const Page = @import("../Page.zig");
-
-const js = @import("js.zig");
-const v8 = js.v8;
-
-const Env = @import("Env.zig");
-const bridge = @import("bridge.zig");
-const Context = @import("Context.zig");
-
-const ArenaAllocator = std.heap.ArenaAllocator;
-const IS_DEBUG = @import("builtin").mode == .Debug;
-
-const CONTEXT_ARENA_RETAIN = 1024 * 64;
-
-// ExecutionWorld closely models a JS World.
-// https://chromium.googlesource.com/chromium/src/+/master/third_party/blink/renderer/bindings/core/v8/V8BindingDesign.md#World
-// https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/scripting/ExecutionWorld
-const ExecutionWorld = @This();
-
-env: *Env,
-
-// Arena whose lifetime is for a single page load. Where
-// the call_arena lives for a single function call, the context_arena
-// lives for the lifetime of the entire page. The allocator will be
-// owned by the Context, but the arena itself is owned by the ExecutionWorld
-// so that we can re-use it from context to context.
-context_arena: ArenaAllocator,
-
-// Currently a context maps to a Browser's Page. Here though, it's only a
-// mechanism to organization page-specific memory. The ExecutionWorld
-// does all the work, but having all page-specific data structures
-// grouped together helps keep things clean.
-context: ?Context = null,
-
-// no init, must be initialized via env.newExecutionWorld()
-
-pub fn deinit(self: *ExecutionWorld) void {
-    if (self.context != null) {
-        self.removeContext();
-    }
-    self.context_arena.deinit();
-}
-
-// Only the top Context in the Main ExecutionWorld should hold a handle_scope.
-// A js.HandleScope is like an arena. Once created, any "Local" that
-// v8 creates will be released (or at least, releasable by the v8 GC)
-// when the handle_scope is freed.
-// We also maintain our own "context_arena" which allows us to have
-// all page related memory easily managed.
-pub fn createContext(self: *ExecutionWorld, page: *Page, enter: bool) !*Context {
-    lp.assert(self.context == null, "ExecptionWorld.createContext has context", .{});
-
-    const env = self.env;
-    const isolate = env.isolate;
-    const arena = self.context_arena.allocator();
-
-    var hs: js.HandleScope = undefined;
-    hs.init(isolate);
-    defer hs.deinit();
-
-    // Get the global template that was created once per isolate
-    const global_template: *const v8.ObjectTemplate = @ptrCast(@alignCast(v8.v8__Eternal__Get(&env.global_template, isolate.handle).?));
-    const v8_context = v8.v8__Context__New(isolate.handle, global_template, null).?;
-
-    // Create the v8::Context and wrap it in a v8::Global
-    var context_global: v8.Global = undefined;
-    v8.v8__Global__New(isolate.handle, v8_context, &context_global);
-
-    // our window wrapped in a v8::Global
-    const global_obj = v8.v8__Context__Global(v8_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 = env.context_id;
-    env.context_id = context_id + 1;
-
-    self.context = Context{
-        .page = page,
-        .id = context_id,
-        .entered = enter,
-        .isolate = isolate,
-        .handle = context_global,
-        .templates = env.templates,
-        .script_manager = &page._script_manager,
-        .call_arena = page.call_arena,
-        .arena = arena,
-    };
-
-    var context = &self.context.?;
-    try context.identity_map.putNoClobber(arena, @intFromPtr(page.window), global_global);
-
-    // 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(&self.context.?));
-    v8.v8__Context__SetEmbedderData(v8_context, 1, @ptrCast(data.handle));
-
-    return &self.context.?;
-}
-
-pub fn removeContext(self: *ExecutionWorld) void {
-    var context = &(self.context orelse return);
-    context.deinit();
-    self.context = null;
-
-    self.env.isolate.notifyContextDisposed();
-    _ = self.context_arena.reset(.{ .retain_with_limit = CONTEXT_ARENA_RETAIN });
-}

src/browser/js/Function.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -22,8 +22,6 @@ const v8 = js.v8;
 
 const log = @import("../../log.zig");
 
-const Allocator = std.mem.Allocator;
-
 const Function = @This();
 
 local: *const js.Local,
@@ -71,7 +69,15 @@ pub fn newInstance(self: *const Function, caught: *js.TryCatch.Caught) !js.Objec
 
 pub fn call(self: *const Function, comptime T: type, args: anytype) !T {
     var caught: js.TryCatch.Caught = undefined;
-    return self._tryCallWithThis(T, self.getThis(), args, &caught) catch |err| {
+    return self._tryCallWithThis(T, self.getThis(), args, &caught, .{}) catch |err| {
+        log.warn(.js, "call caught", .{ .err = err, .caught = caught });
+        return err;
+    };
+}
+
+pub fn callRethrow(self: *const Function, comptime T: type, args: anytype) !T {
+    var caught: js.TryCatch.Caught = undefined;
+    return self._tryCallWithThis(T, self.getThis(), args, &caught, .{ .rethrow = true }) catch |err| {
         log.warn(.js, "call caught", .{ .err = err, .caught = caught });
         return err;
     };
@@ -79,21 +85,24 @@ pub fn call(self: *const Function, comptime T: type, args: anytype) !T {
 
 pub fn callWithThis(self: *const Function, comptime T: type, this: anytype, args: anytype) !T {
     var caught: js.TryCatch.Caught = undefined;
-    return self._tryCallWithThis(T, this, args, &caught) catch |err| {
+    return self._tryCallWithThis(T, this, args, &caught, .{}) catch |err| {
         log.warn(.js, "callWithThis caught", .{ .err = err, .caught = caught });
         return err;
     };
 }
 
 pub fn tryCall(self: *const Function, comptime T: type, args: anytype, caught: *js.TryCatch.Caught) !T {
-    return self._tryCallWithThis(T, self.getThis(), args, caught);
+    return self._tryCallWithThis(T, self.getThis(), args, caught, .{});
 }
 
 pub fn tryCallWithThis(self: *const Function, comptime T: type, this: anytype, args: anytype, caught: *js.TryCatch.Caught) !T {
-    return self._tryCallWithThis(T, this, args, caught);
+    return self._tryCallWithThis(T, this, args, caught, .{});
 }
 
-pub fn _tryCallWithThis(self: *const Function, comptime T: type, this: anytype, args: anytype, caught: *js.TryCatch.Caught) !T {
+const CallOpts = struct {
+    rethrow: bool = false,
+};
+fn _tryCallWithThis(self: *const Function, comptime T: type, this: anytype, args: anytype, caught: *js.TryCatch.Caught, comptime opts: CallOpts) !T {
     caught.* = .{};
     const local = self.local;
 
@@ -147,6 +156,10 @@ pub fn _tryCallWithThis(self: *const Function, comptime T: type, this: anytype,
     defer try_catch.deinit();
 
     const handle = v8.v8__Function__Call(self.handle, local.handle, js_this.handle, @as(c_int, @intCast(js_args.len)), c_args) orelse {
+        if ((comptime opts.rethrow) and try_catch.hasCaught()) {
+            try_catch.rethrow();
+            return error.TryCatchRethrow;
+        }
         caught.* = try_catch.caughtOrError(local.call_arena, error.JSExecCallback);
         return error.JSExecCallback;
     };

src/browser/js/HandleScope.zig

@@ -28,7 +28,11 @@ handle: v8.HandleScope,
 // value, as v8 will then have taken the address of the function-scopped (and no
 // longer valid) local.
 pub fn init(self: *HandleScope, isolate: js.Isolate) void {
-    v8.v8__HandleScope__CONSTRUCT(&self.handle, isolate.handle);
+    self.initWithIsolateHandle(isolate.handle);
+}
+
+pub fn initWithIsolateHandle(self: *HandleScope, isolate: *v8.Isolate) void {
+    v8.v8__HandleScope__CONSTRUCT(&self.handle, isolate);
 }
 
 pub fn deinit(self: *HandleScope) void {

src/browser/js/Inspector.zig

@@ -23,99 +23,76 @@ const v8 = js.v8;
 const TaggedOpaque = @import("TaggedOpaque.zig");
 
 const Allocator = std.mem.Allocator;
-const RndGen = std.Random.DefaultPrng;
 
 const CONTEXT_GROUP_ID = 1;
 const CLIENT_TRUST_LEVEL = 1;
+const IS_DEBUG = @import("builtin").mode == .Debug;
 
+// Inspector exists for the lifetime of the Isolate/Env. 1 Isolate = 1 Inspector.
+// It combines the v8.Inspector and the v8.InspectorClientImpl. The v8.InspectorClientImpl
+// is our own implementation that fulfills the InspectorClient API, i.e. it's the
+// mechanism v8 provides to let us tweak how the inspector works. For example, it
+// Below, you'll find a few pub export fn v8_inspector__Client__IMPL__XYZ functions
+// which is our implementation of what the v8::Inspector requires of our Client
+// (not much at all)
 const Inspector = @This();
 
-handle: *v8.Inspector,
+unique_id: i64,
 isolate: *v8.Isolate,
-client: Client,
-channel: Channel,
-session: Session,
-rnd: RndGen = RndGen.init(0),
+handle: *v8.Inspector,
+client: *v8.InspectorClientImpl,
 default_context: ?v8.Global,
+session: ?Session,
 
-// We expect allocator to be an arena
-// Note: This initializes the pre-allocated inspector in-place
-pub fn init(self: *Inspector, isolate: *v8.Isolate, ctx: anytype) !void {
-    const ContextT = @TypeOf(ctx);
+pub fn init(allocator: Allocator, isolate: *v8.Isolate) !*Inspector {
+    const self = try allocator.create(Inspector);
+    errdefer allocator.destroy(self);
 
-    const Container = switch (@typeInfo(ContextT)) {
-        .@"struct" => ContextT,
-        .pointer => |ptr| ptr.child,
-        .void => NoopInspector,
-        else => @compileError("invalid context type"),
-    };
-    // If necessary, turn a void context into something we can safely ptrCast
-    const safe_context: *anyopaque = if (ContextT == void) @ptrCast(@constCast(&{})) else ctx;
-
-    // Initialize the fields that callbacks need first
     self.* = .{
-        .handle = undefined,
+        .unique_id = 1,
+        .session = null,
         .isolate = isolate,
         .client = undefined,
-        .channel = undefined,
-        .rnd = RndGen.init(0),
+        .handle = undefined,
         .default_context = null,
-        .session = undefined,
     };
 
-    // Create client and set inspector data BEFORE creating the inspector
-    // because V8 will call generateUniqueId during inspector creation
-    const client = Client.init();
-    self.client = client;
-    client.setInspector(self);
+    self.client = v8.v8_inspector__Client__IMPL__CREATE();
+    errdefer v8.v8_inspector__Client__IMPL__DELETE(self.client);
+    v8.v8_inspector__Client__IMPL__SET_DATA(self.client, self);
 
-    // Now create the inspector - generateUniqueId will work because data is set
-    const handle = v8.v8_inspector__Inspector__Create(isolate, client.handle).?;
-    self.handle = handle;
+    self.handle = v8.v8_inspector__Inspector__Create(isolate, self.client).?;
+    errdefer v8.v8_inspector__Inspector__DELETE(self.handle);
 
-    // Create the channel
-    const channel = Channel.init(
-        safe_context,
-        Container.onInspectorResponse,
-        Container.onInspectorEvent,
-        Container.onRunMessageLoopOnPause,
-        Container.onQuitMessageLoopOnPause,
-        isolate,
-    );
-    self.channel = channel;
-    channel.setInspector(self);
-
-    // Create the session
-    const session_handle = v8.v8_inspector__Inspector__Connect(
-        handle,
-        CONTEXT_GROUP_ID,
-        channel.handle,
-        CLIENT_TRUST_LEVEL,
-    ).?;
-    self.session = .{ .handle = session_handle };
+    return self;
 }
 
-pub fn deinit(self: *const Inspector) void {
+pub fn deinit(self: *const Inspector, allocator: Allocator) void {
     var hs: v8.HandleScope = undefined;
     v8.v8__HandleScope__CONSTRUCT(&hs, self.isolate);
     defer v8.v8__HandleScope__DESTRUCT(&hs);
 
-    self.session.deinit();
-    self.client.deinit();
-    self.channel.deinit();
+    if (self.session) |*s| {
+        s.deinit();
+    }
+    v8.v8_inspector__Client__IMPL__DELETE(self.client);
     v8.v8_inspector__Inspector__DELETE(self.handle);
+    allocator.destroy(self);
 }
 
-pub fn send(self: *const Inspector, msg: []const u8) void {
-    // Can't assume the main Context exists (with its HandleScope)
-    // available when doing this. Pages (and thus the HandleScope)
-    // comes and goes, but CDP can keep sending messages.
-    const isolate = self.isolate;
-    var temp_scope: v8.HandleScope = undefined;
-    v8.v8__HandleScope__CONSTRUCT(&temp_scope, isolate);
-    defer v8.v8__HandleScope__DESTRUCT(&temp_scope);
+pub fn startSession(self: *Inspector, ctx: anytype) *Session {
+    if (comptime IS_DEBUG) {
+        std.debug.assert(self.session == null);
+    }
 
-    self.session.dispatchProtocolMessage(isolate, msg);
+    self.session = @as(Session, undefined);
+    Session.init(&self.session.?, self, ctx);
+    return &self.session.?;
+}
+
+pub fn stopSession(self: *Inspector) void {
+    self.session.?.deinit();
+    self.session = null;
 }
 
 // From CDP docs
@@ -151,8 +128,8 @@ pub fn contextCreated(
     }
 }
 
-pub fn contextDestroyed(self: *Inspector, local: *const js.Local) void {
-    v8.v8_inspector__Inspector__ContextDestroyed(self.handle, local.handle);
+pub fn contextDestroyed(self: *Inspector, context: *const v8.Context) void {
+    v8.v8_inspector__Inspector__ContextDestroyed(self.handle, context);
 }
 
 pub fn resetContextGroup(self: *const Inspector) void {
@@ -163,51 +140,6 @@ pub fn resetContextGroup(self: *const Inspector) void {
     v8.v8_inspector__Inspector__ResetContextGroup(self.handle, CONTEXT_GROUP_ID);
 }
 
-// Retrieves the RemoteObject for a given value.
-// The value is loaded through the ExecutionWorld's mapZigInstanceToJs function,
-// just like a method return value. Therefore, if we've mapped this
-// value before, we'll get the existing js.Global(js.Object) and if not
-// we'll create it and track it for cleanup when the context ends.
-pub fn getRemoteObject(
-    self: *const Inspector,
-    local: *const js.Local,
-    group: []const u8,
-    value: anytype,
-) !RemoteObject {
-    const js_val = try local.zigValueToJs(value, .{});
-
-    // We do not want to expose this as a parameter for now
-    const generate_preview = false;
-    return self.session.wrapObject(
-        local.isolate.handle,
-        local.handle,
-        js_val.handle,
-        group,
-        generate_preview,
-    );
-}
-
-// Gets a value by object ID regardless of which context it is in.
-// Our TaggedOpaque stores the "resolved" ptr value (the most specific _type,
-// e.g. we store the ptr to the Div not the EventTarget). But, this is asking for
-// the pointer to the Node, so we need to use the same resolution mechanism which
-// is used when we're calling a function to turn the Div into a Node, which is
-// what TaggedOpaque.fromJS does.
-pub fn getNodePtr(self: *const Inspector, allocator: Allocator, object_id: []const u8, local: *js.Local) !*anyopaque {
-    // just to indicate that the caller is responsible for ensure there's a local environment
-    _ = local;
-    const unwrapped = try self.session.unwrapObject(allocator, object_id);
-    // The values context and groupId are not used here
-    const js_val = unwrapped.value;
-    if (!v8.v8__Value__IsObject(js_val)) {
-        return error.ObjectIdIsNotANode;
-    }
-
-    const Node = @import("../webapi/Node.zig");
-    // Cast to *const v8.Object for typeTaggedAnyOpaque
-    return TaggedOpaque.fromJS(*Node, @ptrCast(js_val)) catch return error.ObjectIdIsNotANode;
-}
-
 pub const RemoteObject = struct {
     handle: *v8.RemoteObject,
 
@@ -254,20 +186,109 @@ pub const RemoteObject = struct {
     }
 };
 
-const Session = struct {
+// Combines a v8::InspectorSession and a v8::InspectorChannelImpl. The
+// InspectorSession is for zig -> v8 (sending messages to the inspector). The
+// Channel is for v8 -> zig, getting events from the Inspector (that we'll pass
+// back ot some opaque context, i.e the CDP BrowserContext).
+// The channel callbacks are defined below, as:
+//   pub export fn v8_inspector__Channel__IMPL__XYZ
+pub const Session = struct {
+    inspector: *Inspector,
     handle: *v8.InspectorSession,
+    channel: *v8.InspectorChannelImpl,
 
-    fn deinit(self: Session) void {
-        v8.v8_inspector__Session__DELETE(self.handle);
+    // callbacks
+    ctx: *anyopaque,
+    onNotif: *const fn (ctx: *anyopaque, msg: []const u8) void,
+    onResp: *const fn (ctx: *anyopaque, call_id: u32, msg: []const u8) void,
+
+    fn init(self: *Session, inspector: *Inspector, ctx: anytype) void {
+        const Container = @typeInfo(@TypeOf(ctx)).pointer.child;
+
+        const channel = v8.v8_inspector__Channel__IMPL__CREATE(inspector.isolate);
+        const handle = v8.v8_inspector__Inspector__Connect(
+            inspector.handle,
+            CONTEXT_GROUP_ID,
+            channel,
+            CLIENT_TRUST_LEVEL,
+        ).?;
+        v8.v8_inspector__Channel__IMPL__SET_DATA(channel, self);
+
+        self.* = .{
+            .ctx = ctx,
+            .handle = handle,
+            .channel = channel,
+            .inspector = inspector,
+            .onResp = Container.onInspectorResponse,
+            .onNotif = Container.onInspectorEvent,
+        };
     }
 
-    fn dispatchProtocolMessage(self: Session, isolate: *v8.Isolate, msg: []const u8) void {
+    fn deinit(self: *const Session) void {
+        v8.v8_inspector__Session__DELETE(self.handle);
+        v8.v8_inspector__Channel__IMPL__DELETE(self.channel);
+    }
+
+    pub fn send(self: *const Session, msg: []const u8) void {
+        const isolate = self.inspector.isolate;
+        var hs: v8.HandleScope = undefined;
+        v8.v8__HandleScope__CONSTRUCT(&hs, isolate);
+        defer v8.v8__HandleScope__DESTRUCT(&hs);
+
         v8.v8_inspector__Session__dispatchProtocolMessage(
             self.handle,
             isolate,
             msg.ptr,
             msg.len,
         );
+
+        v8.v8__Isolate__PerformMicrotaskCheckpoint(isolate);
+    }
+
+    // Gets a value by object ID regardless of which context it is in.
+    // Our TaggedOpaque stores the "resolved" ptr value (the most specific _type,
+    // e.g. we store the ptr to the Div not the EventTarget). But, this is asking for
+    // the pointer to the Node, so we need to use the same resolution mechanism which
+    // is used when we're calling a function to turn the Div into a Node, which is
+    // what TaggedOpaque.fromJS does.
+    pub fn getNodePtr(self: *const Session, allocator: Allocator, object_id: []const u8, local: *js.Local) !*anyopaque {
+        // just to indicate that the caller is responsible for ensuring there's a local environment
+        _ = local;
+
+        const unwrapped = try self.unwrapObject(allocator, object_id);
+        // The values context and groupId are not used here
+        const js_val = unwrapped.value;
+        if (!v8.v8__Value__IsObject(js_val)) {
+            return error.ObjectIdIsNotANode;
+        }
+
+        const Node = @import("../webapi/Node.zig");
+        // Cast to *const v8.Object for typeTaggedAnyOpaque
+        return TaggedOpaque.fromJS(*Node, @ptrCast(js_val)) catch return error.ObjectIdIsNotANode;
+    }
+
+    // Retrieves the RemoteObject for a given value.
+    // The value is loaded through the ExecutionWorld's mapZigInstanceToJs function,
+    // just like a method return value. Therefore, if we've mapped this
+    // value before, we'll get the existing js.Global(js.Object) and if not
+    // we'll create it and track it for cleanup when the context ends.
+    pub fn getRemoteObject(
+        self: *const Session,
+        local: *const js.Local,
+        group: []const u8,
+        value: anytype,
+    ) !RemoteObject {
+        const js_val = try local.zigValueToJs(value, .{});
+
+        // We do not want to expose this as a parameter for now
+        const generate_preview = false;
+        return self.wrapObject(
+            local.isolate.handle,
+            local.handle,
+            js_val.handle,
+            group,
+            generate_preview,
+        );
     }
 
     fn wrapObject(
@@ -334,84 +355,6 @@ const UnwrappedObject = struct {
     object_group: ?[]const u8,
 };
 
-const Channel = struct {
-    handle: *v8.InspectorChannelImpl,
-
-    // callbacks
-    ctx: *anyopaque,
-    onNotif: onNotifFn = undefined,
-    onResp: onRespFn = undefined,
-    onRunMessageLoopOnPause: onRunMessageLoopOnPauseFn = undefined,
-    onQuitMessageLoopOnPause: onQuitMessageLoopOnPauseFn = undefined,
-
-    pub const onNotifFn = *const fn (ctx: *anyopaque, msg: []const u8) void;
-    pub const onRespFn = *const fn (ctx: *anyopaque, call_id: u32, msg: []const u8) void;
-    pub const onRunMessageLoopOnPauseFn = *const fn (ctx: *anyopaque, context_group_id: u32) void;
-    pub const onQuitMessageLoopOnPauseFn = *const fn (ctx: *anyopaque) void;
-
-    fn init(
-        ctx: *anyopaque,
-        onResp: onRespFn,
-        onNotif: onNotifFn,
-        onRunMessageLoopOnPause: onRunMessageLoopOnPauseFn,
-        onQuitMessageLoopOnPause: onQuitMessageLoopOnPauseFn,
-        isolate: *v8.Isolate,
-    ) Channel {
-        const handle = v8.v8_inspector__Channel__IMPL__CREATE(isolate);
-        return .{
-            .handle = handle,
-            .ctx = ctx,
-            .onResp = onResp,
-            .onNotif = onNotif,
-            .onRunMessageLoopOnPause = onRunMessageLoopOnPause,
-            .onQuitMessageLoopOnPause = onQuitMessageLoopOnPause,
-        };
-    }
-
-    fn deinit(self: Channel) void {
-        v8.v8_inspector__Channel__IMPL__DELETE(self.handle);
-    }
-
-    fn setInspector(self: Channel, inspector: *anyopaque) void {
-        v8.v8_inspector__Channel__IMPL__SET_DATA(self.handle, inspector);
-    }
-
-    fn resp(self: Channel, call_id: u32, msg: []const u8) void {
-        self.onResp(self.ctx, call_id, msg);
-    }
-
-    fn notif(self: Channel, msg: []const u8) void {
-        self.onNotif(self.ctx, msg);
-    }
-};
-
-const Client = struct {
-    handle: *v8.InspectorClientImpl,
-
-    fn init() Client {
-        return .{ .handle = v8.v8_inspector__Client__IMPL__CREATE() };
-    }
-
-    fn deinit(self: Client) void {
-        v8.v8_inspector__Client__IMPL__DELETE(self.handle);
-    }
-
-    fn setInspector(self: Client, inspector: *anyopaque) void {
-        v8.v8_inspector__Client__IMPL__SET_DATA(self.handle, inspector);
-    }
-};
-
-const NoopInspector = struct {
-    pub fn onInspectorResponse(_: *anyopaque, _: u32, _: []const u8) void {}
-    pub fn onInspectorEvent(_: *anyopaque, _: []const u8) void {}
-    pub fn onRunMessageLoopOnPause(_: *anyopaque, _: u32) void {}
-    pub fn onQuitMessageLoopOnPause(_: *anyopaque) void {}
-};
-
-fn fromData(data: *anyopaque) *Inspector {
-    return @ptrCast(@alignCast(data));
-}
-
 pub fn getTaggedOpaque(value: *const v8.Value) ?*TaggedOpaque {
     if (!v8.v8__Value__IsObject(value)) {
         return null;
@@ -421,9 +364,8 @@ pub fn getTaggedOpaque(value: *const v8.Value) ?*TaggedOpaque {
         return null;
     }
 
-    const external_value = v8.v8__Object__GetInternalField(value, 0).?;
-    const external_data = v8.v8__External__Value(external_value).?;
-    return @ptrCast(@alignCast(external_data));
+    const tao_ptr = v8.v8__Object__GetAlignedPointerFromInternalField(value, 0).?;
+    return @ptrCast(@alignCast(tao_ptr));
 }
 
 fn cZigStringToString(s: v8.CZigString) ?[]const u8 {
@@ -437,24 +379,25 @@ pub export fn v8_inspector__Client__IMPL__generateUniqueId(
     data: *anyopaque,
 ) callconv(.c) i64 {
     const inspector: *Inspector = @ptrCast(@alignCast(data));
-    return inspector.rnd.random().int(i64);
+    const unique_id = inspector.unique_id + 1;
+    inspector.unique_id = unique_id;
+    return unique_id;
 }
 
 pub export fn v8_inspector__Client__IMPL__runMessageLoopOnPause(
     _: *v8.InspectorClientImpl,
     data: *anyopaque,
-    ctx_group_id: c_int,
+    context_group_id: c_int,
 ) callconv(.c) void {
-    const inspector: *Inspector = @ptrCast(@alignCast(data));
-    inspector.channel.onRunMessageLoopOnPause(inspector.channel.ctx, @intCast(ctx_group_id));
+    _ = data;
+    _ = context_group_id;
 }
 
 pub export fn v8_inspector__Client__IMPL__quitMessageLoopOnPause(
     _: *v8.InspectorClientImpl,
     data: *anyopaque,
 ) callconv(.c) void {
-    const inspector: *Inspector = @ptrCast(@alignCast(data));
-    inspector.channel.onQuitMessageLoopOnPause(inspector.channel.ctx);
+    _ = data;
 }
 
 pub export fn v8_inspector__Client__IMPL__runIfWaitingForDebugger(
@@ -493,8 +436,8 @@ pub export fn v8_inspector__Channel__IMPL__sendResponse(
     msg: [*c]u8,
     length: usize,
 ) callconv(.c) void {
-    const inspector: *Inspector = @ptrCast(@alignCast(data));
-    inspector.channel.resp(@as(u32, @intCast(call_id)), msg[0..length]);
+    const session: *Session = @ptrCast(@alignCast(data));
+    session.onResp(session.ctx, @intCast(call_id), msg[0..length]);
 }
 
 pub export fn v8_inspector__Channel__IMPL__sendNotification(
@@ -503,8 +446,8 @@ pub export fn v8_inspector__Channel__IMPL__sendNotification(
     msg: [*c]u8,
     length: usize,
 ) callconv(.c) void {
-    const inspector: *Inspector = @ptrCast(@alignCast(data));
-    inspector.channel.notif(msg[0..length]);
+    const session: *Session = @ptrCast(@alignCast(data));
+    session.onNotif(session.ctx, msg[0..length]);
 }
 
 pub export fn v8_inspector__Channel__IMPL__flushProtocolNotifications(

src/browser/js/Local.zig

@@ -75,6 +75,12 @@ pub fn newArray(self: *const Local, len: u32) js.Array {
     };
 }
 
+/// Creates a new typed array. Memory is owned by JS context.
+/// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Typed_arrays
+pub fn createTypedArray(self: *const Local, comptime array_type: js.ArrayType, size: usize) js.ArrayBufferRef(array_type) {
+    return .init(self, size);
+}
+
 pub fn runMicrotasks(self: *const Local) void {
     self.isolate.performMicrotasksCheckpoint();
 }
@@ -181,11 +187,7 @@ pub fn mapZigInstanceToJs(self: *const Local, js_obj_handle: ?*const v8.Object,
                     .subtype = if (@hasDecl(JsApi.Meta, "subtype")) JsApi.Meta.subype else .node,
                 };
 
-                // Skip setting internal field for the global object (Window)
-                // Window accessors get the instance from context.page.window instead
-                // if (resolved.class_id != @import("../webapi/Window.zig").JsApi.Meta.class_id) {
-                v8.v8__Object__SetInternalField(js_obj.handle, 0, isolate.createExternal(tao));
-                // }
+                v8.v8__Object__SetAlignedPointerInInternalField(js_obj.handle, 0, tao);
             } else {
                 // If the struct is empty, we don't need to do all
                 // the TOA stuff and setting the internal data.
@@ -198,21 +200,28 @@ pub fn mapZigInstanceToJs(self: *const Local, js_obj_handle: ?*const v8.Object,
             // context.global_objects, we want to track it in context.identity_map.
             v8.v8__Global__New(isolate.handle, js_obj.handle, gop.value_ptr);
             if (@hasDecl(JsApi.Meta, "finalizer")) {
-                if (comptime IS_DEBUG) {
-                    // You can normally return a "*Node" and we'll correctly
-                    // handle it as what it really is, e.g. an HTMLScriptElement.
-                    // But for finalizers, we can't do that. I think this
-                    // limitation will be OK - this auto-resolution is largely
-                    // limited to Node -> HtmlElement, none of which has finalizers
-                    std.debug.assert(resolved.class_id == JsApi.Meta.class_id);
+                // It would be great if resolved knew the resolved type, but I
+                // can't figure out how to make that work, since it depends on
+                // the [runtime] `value`.
+                // We need the resolved finalizer, which we have in resolved.
+                // The above if statement would be more clear as:
+                //    if (resolved.finalizer_from_v8) |finalizer| {
+                // But that's a runtime check.
+                // Instead, we check if the base has finalizer. The assumption
+                // here is that if a resolve type has a finalizer, then the base
+                // should have a finalizer too.
+                const fc = try ctx.createFinalizerCallback(gop.value_ptr.*, resolved.ptr, resolved.finalizer_from_zig.?);
+                {
+                    errdefer fc.deinit();
+                    try ctx.finalizer_callbacks.put(ctx.arena, @intFromPtr(resolved.ptr), fc);
                 }
 
-                try ctx.finalizer_callbacks.put(ctx.arena, @intFromPtr(resolved.ptr), .init(value));
+                conditionallyFlagHandoff(value);
                 if (@hasDecl(JsApi.Meta, "weak")) {
                     if (comptime IS_DEBUG) {
                         std.debug.assert(JsApi.Meta.weak == true);
                     }
-                    v8.v8__Global__SetWeakFinalizer(gop.value_ptr, resolved.ptr, JsApi.Meta.finalizer.from_v8, v8.kParameter);
+                    v8.v8__Global__SetWeakFinalizer(gop.value_ptr, fc, resolved.finalizer_from_v8, v8.kParameter);
                 }
             }
             return js_obj;
@@ -303,6 +312,15 @@ pub fn zigValueToJs(self: *const Local, value: anytype, comptime opts: CallOpts)
                 js.Value => return value,
                 js.Exception => return .{ .local = self, .handle = isolate.throwException(value.handle) },
 
+                js.ArrayBufferRef(.int8).Global, js.ArrayBufferRef(.uint8).Global,
+                js.ArrayBufferRef(.uint8_clamped).Global, js.ArrayBufferRef(.int16).Global,
+                js.ArrayBufferRef(.uint16).Global, js.ArrayBufferRef(.int32).Global,
+                js.ArrayBufferRef(.uint32).Global, js.ArrayBufferRef(.float16).Global,
+                js.ArrayBufferRef(.float32).Global, js.ArrayBufferRef(.float64).Global,
+                => {
+                    return .{ .local = self, .handle = value.local(self).handle };
+                },
+
                 inline
                 js.Function,
                 js.Object,
@@ -316,6 +334,7 @@ pub fn zigValueToJs(self: *const Local, value: anytype, comptime opts: CallOpts)
                 js.Value.Temp,
                 js.Object.Global,
                 js.Promise.Global,
+                js.Promise.Temp,
                 js.PromiseResolver.Global,
                 js.Module.Global => return .{ .local = self, .handle = @ptrCast(value.local(self).handle) },
                 else => {}
@@ -473,10 +492,10 @@ pub fn jsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !T {
                 if (ptr.child == u8) {
                     if (ptr.sentinel()) |s| {
                         if (comptime s == 0) {
-                            return self.valueToStringZ(js_val, .{});
+                            return try js_val.toStringSliceZ();
                         }
                     } else {
-                        return self.valueToString(js_val, .{});
+                        return try js_val.toStringSlice();
                     }
                 }
 
@@ -549,10 +568,8 @@ pub fn jsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !T {
         },
         .@"enum" => |e| {
             if (@hasDecl(T, "js_enum_from_string")) {
-                if (!js_val.isString()) {
-                    return error.InvalidArgument;
-                }
-                return std.meta.stringToEnum(T, try self.valueToString(js_val, .{})) orelse return error.InvalidArgument;
+                const js_str = js_val.isString() orelse return error.InvalidArgument;
+                return std.meta.stringToEnum(T, try js_str.toSlice()) orelse return error.InvalidArgument;
             }
             switch (@typeInfo(e.tag_type)) {
                 .int => return std.meta.intToEnum(T, try jsIntToZig(e.tag_type, js_val)),
@@ -614,28 +631,27 @@ fn jsValueToStruct(self: *const Local, comptime T: type, js_val: js.Value) !?T {
             return try obj.persist();
         },
 
-        js.Promise.Global => {
+        js.Promise.Global, js.Promise.Temp => {
             if (!js_val.isPromise()) {
                 return null;
             }
-            const promise = js.Promise{
-                .ctx = self,
+            const js_promise = js.Promise{
+                .local = self,
                 .handle = @ptrCast(js_val.handle),
             };
-            return try promise.persist();
+            return switch (T) {
+                js.Promise.Temp => try js_promise.temp(),
+                js.Promise.Global => try js_promise.persist(),
+                else => unreachable,
+            };
         },
         string.String => {
-            if (!js_val.isString()) {
-                return null;
-            }
-            return try self.valueToStringSSO(js_val, .{ .allocator = self.ctx.call_arena });
+            const js_str = js_val.isString() orelse return null;
+            return try js_str.toSSO(false);
         },
         string.Global => {
-            if (!js_val.isString()) {
-                return null;
-            }
-            // Use arena for persistent strings
-            return .{ .str = try self.valueToStringSSO(js_val, .{ .allocator = self.ctx.arena }) };
+            const js_str = js_val.isString() orelse return null;
+            return try js_str.toSSO(true);
         },
         else => {
             if (!js_val.isObject()) {
@@ -883,7 +899,7 @@ fn probeJsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !Pr
                 }
 
                 if (ptr.child == u8) {
-                    if (js_val.isString()) {
+                    if (v8.v8__Value__IsString(js_val.handle)) {
                         return .{ .ok = {} };
                     }
                     // anything can be coerced into a string
@@ -931,10 +947,11 @@ fn probeJsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !Pr
                         if (js_arr.len() == arr.len) {
                             return .{ .ok = {} };
                         }
-                    } else if (js_val.isString() and arr.child == u8) {
-                        const str = try js_val.toString(self.local);
-                        if (str.lenUtf8(self.isolate) == arr.len) {
-                            return .{ .ok = {} };
+                    } else if (arr.child == u8) {
+                        if (js_val.isString()) |js_str| {
+                            if (js_str.lenUtf8(self.isolate) == arr.len) {
+                                return .{ .ok = {} };
+                            }
                         }
                     }
                     return .{ .invalid = {} };
@@ -947,7 +964,7 @@ fn probeJsValueToZig(self: *const Local, comptime T: type, js_val: js.Value) !Pr
         .@"struct" => {
             // Handle string.String and string.Global specially
             if (T == string.String or T == string.Global) {
-                if (js_val.isString()) {
+                if (v8.v8__Value__IsString(js_val.handle)) {
                     return .{ .ok = {} };
                 }
                 // Anything can be coerced to a string
@@ -1032,9 +1049,12 @@ fn jsUnsignedIntToZig(comptime T: type, max: comptime_int, maybe: u32) !T {
 // This function recursively walks the _type union field (if there is one) to
 // get the most specific class_id possible.
 const Resolved = struct {
+    weak: bool,
     ptr: *anyopaque,
     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,
 };
 pub fn resolveValue(value: anytype) Resolved {
     const T = bridge.Struct(@TypeOf(value));
@@ -1062,13 +1082,28 @@ pub fn resolveValue(value: anytype) Resolved {
 }
 
 fn resolveT(comptime T: type, value: *anyopaque) Resolved {
+    const Meta = T.JsApi.Meta;
     return .{
         .ptr = value,
-        .class_id = T.JsApi.Meta.class_id,
-        .prototype_chain = &T.JsApi.Meta.prototype_chain,
+        .class_id = Meta.class_id,
+        .prototype_chain = &Meta.prototype_chain,
+        .weak = if (@hasDecl(Meta, "weak")) Meta.weak else false,
+        .finalizer_from_v8 = if (@hasDecl(Meta, "finalizer")) Meta.finalizer.from_v8 else null,
+        .finalizer_from_zig = if (@hasDecl(Meta, "finalizer")) Meta.finalizer.from_zig else null,
     };
 }
 
+fn conditionallyFlagHandoff(value: anytype) void {
+    const T = bridge.Struct(@TypeOf(value));
+    if (@hasField(T, "_v8_handoff")) {
+        value._v8_handoff = true;
+        return;
+    }
+    if (@hasField(T, "_proto")) {
+        conditionallyFlagHandoff(value._proto);
+    }
+}
+
 pub fn stackTrace(self: *const Local) !?[]const u8 {
     const isolate = self.isolate;
     const separator = log.separator();
@@ -1080,14 +1115,15 @@ pub fn stackTrace(self: *const Local) !?[]const u8 {
     const frame_count = v8.v8__StackTrace__GetFrameCount(stack_trace_handle);
 
     if (v8.v8__StackTrace__CurrentScriptNameOrSourceURL__STATIC(isolate.handle)) |script| {
-        try writer.print("{s}<{s}>", .{ separator, try self.jsStringToZig(script, .{}) });
+        const stack = js.String{ .local = self, .handle = script };
+        try writer.print("{s}<{f}>", .{ separator, stack });
     }
 
     for (0..@intCast(frame_count)) |i| {
         const frame_handle = v8.v8__StackTrace__GetFrame(stack_trace_handle, isolate.handle, @intCast(i)).?;
         if (v8.v8__StackFrame__GetFunctionName(frame_handle)) |name| {
-            const script = try self.jsStringToZig(name, .{});
-            try writer.print("{s}{s}:{d}", .{ separator, script, v8.v8__StackFrame__GetLineNumber(frame_handle) });
+            const script = js.String{ .local = self, .handle = name };
+            try writer.print("{s}{f}:{d}", .{ separator, script, v8.v8__StackFrame__GetLineNumber(frame_handle) });
         } else {
             try writer.print("{s}<anonymous>:{d}", .{ separator, v8.v8__StackFrame__GetLineNumber(frame_handle) });
         }
@@ -1095,100 +1131,6 @@ pub fn stackTrace(self: *const Local) !?[]const u8 {
     return buf.items;
 }
 
-// == Stringifiers ==
-const ToStringOpts = struct {
-    allocator: ?Allocator = null,
-};
-pub fn valueToString(self: *const Local, js_val: js.Value, opts: ToStringOpts) ![]u8 {
-    return self.valueHandleToString(js_val.handle, opts);
-}
-pub fn valueToStringZ(self: *const Local, js_val: js.Value, opts: ToStringOpts) ![:0]u8 {
-    return self.valueHandleToStringZ(js_val.handle, opts);
-}
-
-pub fn valueHandleToString(self: *const Local, js_val: *const v8.Value, opts: ToStringOpts) ![]u8 {
-    return self._valueToString(false, js_val, opts);
-}
-pub fn valueHandleToStringZ(self: *const Local, js_val: *const v8.Value, opts: ToStringOpts) ![:0]u8 {
-    return self._valueToString(true, js_val, opts);
-}
-
-fn _valueToString(self: *const Local, comptime null_terminate: bool, value_handle: *const v8.Value, opts: ToStringOpts) !(if (null_terminate) [:0]u8 else []u8) {
-    var resolved_value_handle = value_handle;
-    if (v8.v8__Value__IsSymbol(value_handle)) {
-        const symbol_handle = v8.v8__Symbol__Description(@ptrCast(value_handle), self.isolate.handle).?;
-        resolved_value_handle = @ptrCast(symbol_handle);
-    }
-
-    const string_handle = v8.v8__Value__ToString(resolved_value_handle, self.handle) orelse {
-        return error.JsException;
-    };
-
-    return self._jsStringToZig(null_terminate, string_handle, opts);
-}
-
-pub fn jsStringToZig(self: *const Local, str: anytype, opts: ToStringOpts) ![]u8 {
-    return self._jsStringToZig(false, str, opts);
-}
-pub fn jsStringToZigZ(self: *const Local, str: anytype, opts: ToStringOpts) ![:0]u8 {
-    return self._jsStringToZig(true, str, opts);
-}
-fn _jsStringToZig(self: *const Local, comptime null_terminate: bool, str: anytype, opts: ToStringOpts) !(if (null_terminate) [:0]u8 else []u8) {
-    const handle = if (@TypeOf(str) == js.String) str.handle else str;
-
-    const len = v8.v8__String__Utf8Length(handle, self.isolate.handle);
-    const allocator = opts.allocator orelse self.call_arena;
-    const buf = try (if (comptime null_terminate) allocator.allocSentinel(u8, @intCast(len), 0) else allocator.alloc(u8, @intCast(len)));
-    const n = v8.v8__String__WriteUtf8(handle, self.isolate.handle, buf.ptr, buf.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
-    std.debug.assert(n == len);
-
-    return buf;
-}
-
-// Convert JS string to string.String with SSO
-pub fn valueToStringSSO(self: *const Local, js_val: js.Value, opts: ToStringOpts) !string.String {
-    const string_handle = v8.v8__Value__ToString(js_val.handle, self.handle) orelse {
-        return error.JsException;
-    };
-    return self.jsStringToStringSSO(string_handle, opts);
-}
-
-pub fn jsStringToStringSSO(self: *const Local, str: anytype, opts: ToStringOpts) !string.String {
-    const handle = if (@TypeOf(str) == js.String) str.handle else str;
-    const len: usize = @intCast(v8.v8__String__Utf8Length(handle, self.isolate.handle));
-
-    if (len <= 12) {
-        var content: [12]u8 = undefined;
-        const n = v8.v8__String__WriteUtf8(handle, self.isolate.handle, &content[0], content.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
-        if (comptime IS_DEBUG) {
-            std.debug.assert(n == len);
-        }
-        // Weird that we do this _after_, but we have to..I've seen weird issues
-        // in ReleaseMode where v8 won't write to content if it starts off zero
-        // initiated
-        @memset(content[len..], 0);
-        return .{ .len = @intCast(len), .payload = .{ .content = content } };
-    }
-
-    const allocator = opts.allocator orelse self.call_arena;
-    const buf = try allocator.alloc(u8, len);
-    const n = v8.v8__String__WriteUtf8(handle, self.isolate.handle, buf.ptr, buf.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
-    if (comptime IS_DEBUG) {
-        std.debug.assert(n == len);
-    }
-
-    var prefix: [4]u8 = @splat(0);
-    @memcpy(&prefix, buf[0..4]);
-
-    return .{
-        .len = @intCast(len),
-        .payload = .{ .heap = .{
-            .prefix = prefix,
-            .ptr = buf.ptr,
-        } },
-    };
-}
-
 // == Promise Helpers ==
 pub fn rejectPromise(self: *const Local, value: anytype) !js.Promise {
     var resolver = js.PromiseResolver.init(self);
@@ -1233,18 +1175,19 @@ fn _debugValue(self: *const Local, js_val: js.Value, seen: *std.AutoHashMapUnman
 
         if (js_val.isSymbol()) {
             const symbol_handle = v8.v8__Symbol__Description(@ptrCast(js_val.handle), self.isolate.handle).?;
-            const js_sym_str = try self.valueToString(.{ .local = self, .handle = symbol_handle }, .{});
-            return writer.print("{s} (symbol)", .{js_sym_str});
+            if (v8.v8__Value__IsUndefined(symbol_handle)) {
+                return writer.writeAll("undefined (symbol)");
+            }
+            return writer.print("{f} (symbol)", .{js.String{ .local = self, .handle = @ptrCast(symbol_handle) }});
         }
-        const js_type = try self.jsStringToZig(js_val.typeOf(), .{});
-        const js_val_str = try self.valueToString(js_val, .{});
+        const js_val_str = try js_val.toStringSlice();
         if (js_val_str.len > 2000) {
             try writer.writeAll(js_val_str[0..2000]);
             try writer.writeAll(" ... (truncated)");
         } else {
             try writer.writeAll(js_val_str);
         }
-        return writer.print(" ({s})", .{js_type});
+        return writer.print(" ({f})", .{js_val.typeOf()});
     }
 
     const js_obj = js_val.toObject();
@@ -1266,7 +1209,7 @@ fn _debugValue(self: *const Local, js_val: js.Value, seen: *std.AutoHashMapUnman
     }
     const own_len = js_obj.getOwnPropertyNames().len();
     if (own_len == 0) {
-        const js_val_str = try self.valueToString(js_val, .{});
+        const js_val_str = try js_val.toStringSlice();
         if (js_val_str.len > 2000) {
             try writer.writeAll(js_val_str[0..2000]);
             return writer.writeAll(" ... (truncated)");
@@ -1281,10 +1224,11 @@ fn _debugValue(self: *const Local, js_val: js.Value, seen: *std.AutoHashMapUnman
             try writer.writeByte('\n');
         }
         const field_name = try names_arr.get(@intCast(i));
-        const name = try self.valueToString(field_name, .{});
+        const name = try field_name.toStringSlice();
         try writer.splatByteAll(' ', depth);
         try writer.writeAll(name);
         try writer.writeAll(": ");
+
         const field_val = try js_obj.get(name);
         try self._debugValue(field_val, seen, depth + 1, writer);
         if (i != len - 1) {

src/browser/js/Module.zig

@@ -131,7 +131,7 @@ const Requests = struct {
 const Request = struct {
     handle: *const v8.ModuleRequest,
 
-    pub fn specifier(self: Request) *const v8.String {
-        return v8.v8__ModuleRequest__GetSpecifier(self.handle).?;
+    pub fn specifier(self: Request, local: *const js.Local) js.String {
+        return .{ .local = local, .handle = v8.v8__ModuleRequest__GetSpecifier(self.handle).? };
     }
 };

src/browser/js/Object.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -22,10 +22,6 @@ const v8 = js.v8;
 
 const IS_DEBUG = @import("builtin").mode == .Debug;
 
-const Context = @import("Context.zig");
-
-const Allocator = std.mem.Allocator;
-
 const Object = @This();
 
 local: *const js.Local,
@@ -80,10 +76,6 @@ pub fn defineOwnProperty(self: Object, name: []const u8, value: js.Value, attr:
     }
 }
 
-pub fn toString(self: Object) ![]const u8 {
-    return self.local.ctx.valueToString(self.toValue(), .{});
-}
-
 pub fn toValue(self: Object) js.Value {
     return .{
         .local = self.local,
@@ -201,8 +193,8 @@ pub const NameIterator = struct {
         }
         self.idx += 1;
 
-        const js_val_handle = v8.v8__Object__GetIndex(@ptrCast(self.handle), self.local.handle, idx) orelse return error.JsException;
-        const js_val = js.Value{ .local = self.local, .handle = js_val_handle };
-        return try self.local.valueToString(js_val, .{});
+        const local = self.local;
+        const js_val_handle = v8.v8__Object__GetIndex(@ptrCast(self.handle), local.handle, idx) orelse return error.JsException;
+        return try js.Value.toStringSlice(.{ .local = local, .handle = js_val_handle });
     }
 };

src/browser/js/Private.zig

@@ -0,0 +1,42 @@
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const js = @import("js.zig");
+const v8 = js.v8;
+
+const Private = @This();
+
+// Unlike most types, we always store the Private as a Global. It makes more
+// sense for this type given how it's used.
+handle: v8.Global,
+
+pub fn init(isolate: *v8.Isolate, name: []const u8) Private {
+    const v8_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
+    const private_handle = v8.v8__Private__New(isolate, v8_name);
+
+    var global: v8.Global = undefined;
+    v8.v8__Global__New(isolate, private_handle, &global);
+
+    return .{
+        .handle = global,
+    };
+}
+
+pub fn deinit(self: *Private) void {
+    v8.v8__Global__Reset(&self.handle);
+}

src/browser/js/Promise.zig

@@ -47,25 +47,49 @@ pub fn thenAndCatch(self: Promise, on_fulfilled: js.Function, on_rejected: js.Fu
     }
     return error.PromiseChainFailed;
 }
+
 pub fn persist(self: Promise) !Global {
+    return self._persist(true);
+}
+
+pub fn temp(self: Promise) !Temp {
+    return self._persist(false);
+}
+
+fn _persist(self: *const Promise, comptime is_global: bool) !(if (is_global) Global else Temp) {
     var ctx = self.local.ctx;
+
     var global: v8.Global = undefined;
     v8.v8__Global__New(ctx.isolate.handle, self.handle, &global);
-    try ctx.global_promises.append(ctx.arena, global);
+    if (comptime is_global) {
+        try ctx.global_promises.append(ctx.arena, global);
+    } else {
+        try ctx.global_promises_temp.put(ctx.arena, global.data_ptr, global);
+    }
     return .{ .handle = global };
 }
 
-pub const Global = struct {
-    handle: v8.Global,
+pub const Temp = G(0);
+pub const Global = G(1);
 
-    pub fn deinit(self: *Global) void {
-        v8.v8__Global__Reset(&self.handle);
-    }
+fn G(comptime discriminator: u8) type {
+    return struct {
+        handle: v8.Global,
 
-    pub fn local(self: *const Global, l: *const js.Local) Promise {
-        return .{
-            .local = l,
-            .handle = @ptrCast(v8.v8__Global__Get(&self.handle, l.isolate.handle)),
-        };
-    }
-};
+        // makes the types different (G(0) != G(1)), without taking up space
+        comptime _: u8 = discriminator,
+
+        const Self = @This();
+
+        pub fn deinit(self: *Self) void {
+            v8.v8__Global__Reset(&self.handle);
+        }
+
+        pub fn local(self: *const Self, l: *const js.Local) Promise {
+            return .{
+                .local = l,
+                .handle = @ptrCast(v8.v8__Global__Get(&self.handle, l.isolate.handle)),
+            };
+        }
+    };
+}

src/browser/js/PromiseRejection.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -19,6 +19,23 @@
 const js = @import("js.zig");
 const v8 = js.v8;
 
-const Name = @This();
+const PromiseRejection = @This();
 
-handle: *const v8.Name,
+local: *const js.Local,
+handle: *const v8.PromiseRejectMessage,
+
+pub fn promise(self: PromiseRejection) js.Promise {
+    return .{
+        .local = self.local,
+        .handle = v8.v8__PromiseRejectMessage__GetPromise(self.handle).?,
+    };
+}
+
+pub fn reason(self: PromiseRejection) ?js.Value {
+    const value_handle = v8.v8__PromiseRejectMessage__GetValue(self.handle) orelse return null;
+
+    return .{
+        .local = self.local,
+        .handle = value_handle,
+    };
+}

src/browser/js/Scheduler.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -19,9 +19,8 @@
 const std = @import("std");
 const builtin = @import("builtin");
 
-const js = @import("js/js.zig");
-const log = @import("../log.zig");
-const milliTimestamp = @import("../datetime.zig").milliTimestamp;
+const log = @import("../../log.zig");
+const milliTimestamp = @import("../../datetime.zig").milliTimestamp;
 
 const IS_DEBUG = builtin.mode == .Debug;
 
@@ -48,9 +47,15 @@ pub fn init(allocator: std.mem.Allocator) Scheduler {
     };
 }
 
+pub fn deinit(self: *Scheduler) void {
+    finalizeTasks(&self.low_priority);
+    finalizeTasks(&self.high_priority);
+}
+
 const AddOpts = struct {
     name: []const u8 = "",
     low_priority: bool = false,
+    finalizer: ?Finalizer = null,
 };
 pub fn add(self: *Scheduler, ctx: *anyopaque, cb: Callback, run_in_ms: u32, opts: AddOpts) !void {
     if (comptime IS_DEBUG) {
@@ -64,6 +69,7 @@ pub fn add(self: *Scheduler, ctx: *anyopaque, cb: Callback, run_in_ms: u32, opts
         .callback = cb,
         .sequence = seq,
         .name = opts.name,
+        .finalizer = opts.finalizer,
         .run_at = milliTimestamp(.monotonic) + run_in_ms,
     });
 }
@@ -73,6 +79,11 @@ pub fn run(self: *Scheduler) !?u64 {
     return self.runQueue(&self.high_priority);
 }
 
+pub fn hasReadyTasks(self: *Scheduler) bool {
+    const now = milliTimestamp(.monotonic);
+    return queueuHasReadyTask(&self.low_priority, now) or queueuHasReadyTask(&self.high_priority, now);
+}
+
 fn runQueue(self: *Scheduler, queue: *Queue) !?u64 {
     if (queue.count() == 0) {
         return null;
@@ -106,12 +117,28 @@ fn runQueue(self: *Scheduler, queue: *Queue) !?u64 {
     return null;
 }
 
+fn queueuHasReadyTask(queue: *Queue, now: u64) bool {
+    const task = queue.peek() orelse return false;
+    return task.run_at <= now;
+}
+
+fn finalizeTasks(queue: *Queue) void {
+    var it = queue.iterator();
+    while (it.next()) |t| {
+        if (t.finalizer) |func| {
+            func(t.ctx);
+        }
+    }
+}
+
 const Task = struct {
     run_at: u64,
     sequence: u64,
     ctx: *anyopaque,
     name: []const u8,
     callback: Callback,
+    finalizer: ?Finalizer,
 };
 
 const Callback = *const fn (ctx: *anyopaque) anyerror!?u32;
+const Finalizer = *const fn (ctx: *anyopaque) void;

src/browser/js/Snapshot.zig

@@ -202,12 +202,16 @@ pub fn create() !Snapshot {
                     const name = JsApi.Meta.name;
                     const illegal_class_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
                     var maybe_result2: v8.MaybeBool = undefined;
-                    v8.v8__Object__Set(global_obj, context, illegal_class_name, func, &maybe_result2);
+                    v8.v8__Object__DefineOwnProperty(global_obj, context, illegal_class_name, func, 0, &maybe_result2);
                 } else {
                     const name = JsApi.Meta.name;
                     const v8_class_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
                     var maybe_result: v8.MaybeBool = undefined;
-                    v8.v8__Object__Set(global_obj, context, v8_class_name, func, &maybe_result);
+                    var properties: v8.PropertyAttribute = v8.None;
+                    if (@hasDecl(JsApi.Meta, "enumerable") and JsApi.Meta.enumerable == false) {
+                        properties |= v8.DontEnum;
+                    }
+                    v8.v8__Object__DefineOwnProperty(global_obj, context, v8_class_name, func, properties, &maybe_result);
                 }
             }
         }
@@ -261,12 +265,26 @@ pub fn create() !Snapshot {
     };
 }
 
+// Helper to check if a JsApi has a NamedIndexed handler
+fn hasNamedIndexedGetter(comptime JsApi: type) bool {
+    const declarations = @typeInfo(JsApi).@"struct".decls;
+    inline for (declarations) |d| {
+        const value = @field(JsApi, d.name);
+        const T = @TypeOf(value);
+        if (T == bridge.NamedIndexed) {
+            return true;
+        }
+    }
+    return false;
+}
+
 // Count total callbacks needed for external_references array
 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;
 
     inline for (JsApis) |JsApi| {
         // Constructor (only if explicit)
@@ -289,6 +307,10 @@ fn countExternalReferences() comptime_int {
                 if (value.setter != null) count += 1; // setter
             } 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) {
@@ -301,6 +323,19 @@ 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| {
+            if (!hasNamedIndexedGetter(JsApi)) {
+                count += 1;
+            }
+        }
+    }
+
     return count + 1; // +1 for null terminator
 }
 
@@ -311,6 +346,8 @@ fn collectExternalReferences() [countExternalReferences()]isize {
     references[idx] = @bitCast(@intFromPtr(&illegalConstructorCallback));
     idx += 1;
 
+    var has_non_template_property = false;
+
     inline for (JsApis) |JsApi| {
         if (@hasDecl(JsApi, "constructor")) {
             references[idx] = @bitCast(@intFromPtr(JsApi.constructor.func));
@@ -336,6 +373,10 @@ 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;
@@ -357,6 +398,21 @@ 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| {
+            if (!hasNamedIndexedGetter(JsApi)) {
+                references[idx] = @bitCast(@intFromPtr(bridge.unknownObjectPropertyCallback(JsApi)));
+                idx += 1;
+            }
+        }
+    }
+
     return references;
 }
 
@@ -377,9 +433,12 @@ fn generateConstructor(comptime JsApi: type, isolate: *v8.Isolate) *v8.FunctionT
     };
 
     const template = @constCast(v8.v8__FunctionTemplate__New__DEFAULT2(isolate, callback).?);
-    if (!@hasDecl(JsApi.Meta, "empty_with_no_proto")) {
-        const instance_template = v8.v8__FunctionTemplate__InstanceTemplate(template);
-        v8.v8__ObjectTemplate__SetInternalFieldCount(instance_template, 1);
+    {
+        const internal_field_count = comptime countInternalFields(JsApi);
+        if (internal_field_count > 0) {
+            const instance_template = v8.v8__FunctionTemplate__InstanceTemplate(template);
+            v8.v8__ObjectTemplate__SetInternalFieldCount(instance_template, internal_field_count);
+        }
     }
     const name_str = if (@hasDecl(JsApi.Meta, "name")) JsApi.Meta.name else @typeName(JsApi);
     const class_name = v8.v8__String__NewFromUtf8(isolate, name_str.ptr, v8.kNormal, @intCast(name_str.len));
@@ -387,12 +446,51 @@ fn generateConstructor(comptime JsApi: type, isolate: *v8.Isolate) *v8.FunctionT
     return template;
 }
 
+pub fn countInternalFields(comptime JsApi: type) u8 {
+    var last_used_id = 0;
+    var cache_count: u8 = 0;
+
+    inline for (@typeInfo(JsApi).@"struct".decls) |d| {
+        const name: [:0]const u8 = d.name;
+        const value = @field(JsApi, name);
+        const definition = @TypeOf(value);
+
+        switch (definition) {
+            inline bridge.Accessor, bridge.Function => {
+                const cache = value.cache orelse continue;
+                if (cache != .internal) {
+                    continue;
+                }
+                // We assert that they are declared in-order. This isn't necessary
+                // but I don't want to do anything fancy to look for gaps or
+                // duplicates.
+                const internal_id = cache.internal;
+                if (internal_id != last_used_id + 1) {
+                    @compileError(@typeName(JsApi) ++ "." ++ name ++ " has a non-monotonic cache index");
+                }
+                last_used_id = internal_id;
+                cache_count += 1; // this is just last_used, but it's more explicit this way
+            },
+            else => {},
+        }
+    }
+
+    if (@hasDecl(JsApi.Meta, "empty_with_no_proto")) {
+        return cache_count;
+    }
+
+    // we need cache_count internal fields, + 1 for the TAO pointer (the v8 -> Zig)
+    // mapping) itself.
+    return cache_count + 1;
+}
+
 // 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 declarations = @typeInfo(JsApi).@"struct".decls;
+    var has_named_index_getter = false;
 
     inline for (declarations) |d| {
         const name: [:0]const u8 = d.name;
@@ -402,7 +500,7 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
         switch (definition) {
             bridge.Accessor => {
                 const js_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
-                const getter_callback = @constCast(v8.v8__FunctionTemplate__New__DEFAULT2(isolate, value.getter).?);
+                const getter_callback = @constCast(v8.v8__FunctionTemplate__New__Config(isolate, &.{ .callback = value.getter }).?);
                 if (value.setter == null) {
                     if (value.static) {
                         v8.v8__Template__SetAccessorProperty__DEFAULT(@ptrCast(template), js_name, getter_callback);
@@ -413,12 +511,12 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                     if (comptime IS_DEBUG) {
                         std.debug.assert(value.static == false);
                     }
-                    const setter_callback = @constCast(v8.v8__FunctionTemplate__New__DEFAULT2(isolate, value.setter.?).?);
+                    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);
                 }
             },
             bridge.Function => {
-                const function_template = @constCast(v8.v8__FunctionTemplate__New__DEFAULT2(isolate, value.func).?);
+                const function_template = @constCast(v8.v8__FunctionTemplate__New__Config(isolate, &.{ .callback = value.func, .length = value.arity }).?);
                 const js_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
                 if (value.static) {
                     v8.v8__Template__Set(@ptrCast(template), js_name, @ptrCast(function_template), v8.None);
@@ -453,9 +551,10 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                     .flags = v8.kOnlyInterceptStrings | v8.kNonMasking,
                 };
                 v8.v8__ObjectTemplate__SetNamedHandler(instance, &configuration);
+                has_named_index_getter = true;
             },
             bridge.Iterator => {
-                const function_template = @constCast(v8.v8__FunctionTemplate__New__DEFAULT2(isolate, value.func).?);
+                const function_template = @constCast(v8.v8__FunctionTemplate__New__Config(isolate, &.{ .callback = value.func }).?);
                 const js_name = if (value.async)
                     v8.v8__Symbol__GetAsyncIterator(isolate)
                 else
@@ -463,17 +562,29 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
                 v8.v8__Template__Set(@ptrCast(target), js_name, @ptrCast(function_template), v8.None);
             },
             bridge.Property => {
-                // simpleZigValueToJs now returns raw handle directly
-                const js_value = switch (value) {
-                    .int => |v| js.simpleZigValueToJs(.{ .handle = isolate }, v, true, false),
+                const js_value = switch (value.value) {
+                    .null => js.simpleZigValueToJs(.{ .handle = isolate }, null, true, false),
+                    inline .bool, .int, .float, .string => |v| js.simpleZigValueToJs(.{ .handle = isolate }, v, true, false),
                 };
-
                 const js_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
-                // apply it both to the type itself
-                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);
+                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
+                    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
             else => {},
@@ -490,6 +601,23 @@ fn attachClass(comptime JsApi: type, isolate: *v8.Isolate, template: *v8.Functio
         const js_value = v8.v8__String__NewFromUtf8(isolate, JsApi.Meta.name.ptr, v8.kNormal, @intCast(JsApi.Meta.name.len));
         v8.v8__Template__Set(@ptrCast(instance), js_name, js_value, v8.ReadOnly + v8.DontDelete);
     }
+
+    if (comptime IS_DEBUG) {
+        if (!has_named_index_getter) {
+            var configuration: v8.NamedPropertyHandlerConfiguration = .{
+                .getter = bridge.unknownObjectPropertyCallback(JsApi),
+                .setter = null,
+                .query = null,
+                .deleter = null,
+                .enumerator = null,
+                .definer = null,
+                .descriptor = null,
+                .data = null,
+                .flags = v8.kOnlyInterceptStrings | v8.kNonMasking,
+            };
+            v8.v8__ObjectTemplate__SetNamedHandler(instance, &configuration);
+        }
+    }
 }
 
 fn protoIndexLookup(comptime JsApi: type) ?bridge.JsApiLookup.BackingInt {

src/browser/js/String.zig

@@ -18,8 +18,10 @@
 
 const std = @import("std");
 const js = @import("js.zig");
+const SSO = @import("../../string.zig").String;
 
 const Allocator = std.mem.Allocator;
+const IS_DEBUG = @import("builtin").mode == .Debug;
 
 const v8 = js.v8;
 
@@ -28,26 +30,82 @@ const String = @This();
 local: *const js.Local,
 handle: *const v8.String,
 
-pub const ToZigOpts = struct {
-    allocator: ?Allocator = null,
-};
-
-pub fn toZig(self: String, opts: ToZigOpts) ![]u8 {
-    return self._toZig(false, opts);
+pub fn toSlice(self: String) ![]u8 {
+    return self._toSlice(false, self.local.call_arena);
 }
-
-pub fn toZigZ(self: String, opts: ToZigOpts) ![:0]u8 {
-    return self._toZig(true, opts);
+pub fn toSliceZ(self: String) ![:0]u8 {
+    return self._toSlice(true, self.local.call_arena);
 }
+pub fn toSliceWithAlloc(self: String, allocator: Allocator) ![]u8 {
+    return self._toSlice(false, allocator);
+}
+fn _toSlice(self: String, comptime null_terminate: bool, allocator: Allocator) !(if (null_terminate) [:0]u8 else []u8) {
+    const local = self.local;
+    const handle = self.handle;
+    const isolate = local.isolate.handle;
 
-fn _toZig(self: String, comptime null_terminate: bool, opts: ToZigOpts) !(if (null_terminate) [:0]u8 else []u8) {
-    const isolate = self.local.isolate.handle;
-    const allocator = opts.allocator orelse self.local.ctx.call_arena;
-    const len: u32 = @intCast(v8.v8__String__Utf8Length(self.handle, isolate));
-    const buf = if (null_terminate) try allocator.allocSentinel(u8, len, 0) else try allocator.alloc(u8, len);
+    const len = v8.v8__String__Utf8Length(handle, isolate);
+    const buf = try (if (comptime null_terminate) allocator.allocSentinel(u8, @intCast(len), 0) else allocator.alloc(u8, @intCast(len)));
+    const n = v8.v8__String__WriteUtf8(handle, isolate, buf.ptr, buf.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
+    if (comptime IS_DEBUG) {
+        std.debug.assert(n == len);
+    }
 
-    const options = v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8;
-    const n = v8.v8__String__WriteUtf8(self.handle, isolate, buf.ptr, buf.len, options);
-    std.debug.assert(n == len);
     return buf;
 }
+
+pub fn toSSO(self: String, comptime global: bool) !(if (global) SSO.Global else SSO) {
+    if (comptime global) {
+        return .{ .str = try self.toSSOWithAlloc(self.local.ctx.arena) };
+    }
+    return self.toSSOWithAlloc(self.local.call_arena);
+}
+pub fn toSSOWithAlloc(self: String, allocator: Allocator) !SSO {
+    const handle = self.handle;
+    const isolate = self.local.isolate.handle;
+
+    const len: usize = @intCast(v8.v8__String__Utf8Length(handle, isolate));
+
+    if (len <= 12) {
+        var content: [12]u8 = undefined;
+        const n = v8.v8__String__WriteUtf8(handle, isolate, &content[0], content.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
+        if (comptime IS_DEBUG) {
+            std.debug.assert(n == len);
+        }
+        // Weird that we do this _after_, but we have to..I've seen weird issues
+        // in ReleaseMode where v8 won't write to content if it starts off zero
+        // initiated
+        @memset(content[len..], 0);
+        return .{ .len = @intCast(len), .payload = .{ .content = content } };
+    }
+
+    const buf = try allocator.alloc(u8, len);
+    const n = v8.v8__String__WriteUtf8(handle, isolate, buf.ptr, buf.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
+    if (comptime IS_DEBUG) {
+        std.debug.assert(n == len);
+    }
+
+    var prefix: [4]u8 = @splat(0);
+    @memcpy(&prefix, buf[0..4]);
+
+    return .{
+        .len = @intCast(len),
+        .payload = .{ .heap = .{
+            .prefix = prefix,
+            .ptr = buf.ptr,
+        } },
+    };
+}
+
+pub fn format(self: String, writer: *std.Io.Writer) !void {
+    const local = self.local;
+    const handle = self.handle;
+    const isolate = local.isolate.handle;
+
+    var small: [1024]u8 = undefined;
+    const len = v8.v8__String__Utf8Length(handle, isolate);
+    var buf = if (len < 1024) &small else local.call_arena.alloc(u8, @intCast(len)) catch return error.WriteFailed;
+
+    const n = v8.v8__String__WriteUtf8(handle, isolate, buf.ptr, buf.len, v8.NO_NULL_TERMINATION | v8.REPLACE_INVALID_UTF8);
+    return writer.writeAll(buf[0..n]);
+}

src/browser/js/TaggedOpaque.zig

@@ -95,33 +95,6 @@ pub fn fromJS(comptime R: type, js_obj_handle: *const v8.Object) !R {
     }
 
     const internal_field_count = v8.v8__Object__InternalFieldCount(js_obj_handle);
-    // Special case for Window: the global object doesn't have internal fields
-    // Window instance is stored in context.page.window instead
-    if (internal_field_count == 0) {
-        // Normally, this would be an error. All JsObject that map to a Zig type
-        // are either `empty_with_no_proto` (handled above) or have an
-        // interalFieldCount. The only exception to that is the Window...
-        const isolate = v8.v8__Object__GetIsolate(js_obj_handle).?;
-        const context = js.Context.fromIsolate(.{ .handle = isolate });
-
-        const Window = @import("../webapi/Window.zig");
-        if (T == Window) {
-            return context.page.window;
-        }
-
-        // ... Or the window's prototype.
-        // We could make this all comptime-fancy, but it's easier to hard-code
-        // the EventTarget
-
-        const EventTarget = @import("../webapi/EventTarget.zig");
-        if (T == EventTarget) {
-            return context.page.window._proto;
-        }
-
-        // Type not found in Window's prototype chain
-        return error.InvalidArgument;
-    }
-
     // if it isn't an empty struct, then the v8.Object should have an
     // InternalFieldCount > 0, since our toa pointer should be embedded
     // at index 0 of the internal field count.
@@ -133,8 +106,8 @@ pub fn fromJS(comptime R: type, js_obj_handle: *const v8.Object) !R {
         @compileError("unknown Zig type: " ++ @typeName(R));
     }
 
-    const internal_field_handle = v8.v8__Object__GetInternalField(js_obj_handle, 0).?;
-    const tao: *TaggedOpaque = @ptrCast(@alignCast(v8.v8__External__Value(internal_field_handle)));
+    const tao_ptr = v8.v8__Object__GetAlignedPointerFromInternalField(js_obj_handle, 0).?;
+    const tao: *TaggedOpaque = @ptrCast(@alignCast(tao_ptr));
     const expected_type_index = bridge.JsApiLookup.getId(JsApi);
 
     const prototype_chain = tao.prototype_chain[0..tao.prototype_len];

src/browser/js/TryCatch.zig

@@ -20,6 +20,8 @@ const std = @import("std");
 const js = @import("js.zig");
 const v8 = js.v8;
 
+const IS_DEBUG = @import("builtin").mode == .Debug;
+
 const Allocator = std.mem.Allocator;
 
 const TryCatch = @This();
@@ -32,8 +34,19 @@ pub fn init(self: *TryCatch, l: *const js.Local) void {
     v8.v8__TryCatch__CONSTRUCT(&self.handle, l.isolate.handle);
 }
 
+pub fn hasCaught(self: TryCatch) bool {
+    return v8.v8__TryCatch__HasCaught(&self.handle);
+}
+
+pub fn rethrow(self: *TryCatch) void {
+    if (comptime IS_DEBUG) {
+        std.debug.assert(self.hasCaught());
+    }
+    _ = v8.v8__TryCatch__ReThrow(&self.handle);
+}
+
 pub fn caught(self: TryCatch, allocator: Allocator) ?Caught {
-    if (!v8.v8__TryCatch__HasCaught(&self.handle)) {
+    if (self.hasCaught() == false) {
         return null;
     }
 
@@ -46,12 +59,38 @@ pub fn caught(self: TryCatch, allocator: Allocator) ?Caught {
 
     const exception: ?[]const u8 = blk: {
         const handle = v8.v8__TryCatch__Exception(&self.handle) orelse break :blk null;
-        break :blk l.valueHandleToString(@ptrCast(handle), .{ .allocator = allocator }) catch |err| @errorName(err);
+        var js_val = js.Value{ .local = l, .handle = handle };
+
+        // If it's an Error object, try to get the message property
+        if (js_val.isObject()) {
+            const js_obj = js_val.toObject();
+            if (js_obj.has("message")) {
+                js_val = js_obj.get("message") catch break :blk null;
+            }
+        }
+
+        if (js_val.isString()) |js_str| {
+            break :blk js_str.toSliceWithAlloc(allocator) catch |err| @errorName(err);
+        }
+        break :blk null;
     };
 
     const stack: ?[]const u8 = blk: {
         const handle = v8.v8__TryCatch__StackTrace(&self.handle, l.handle) orelse break :blk null;
-        break :blk l.valueHandleToString(@ptrCast(handle), .{ .allocator = allocator }) catch |err| @errorName(err);
+        var js_val = js.Value{ .local = l, .handle = handle };
+
+        // If it's an Error object, try to get the stack property
+        if (js_val.isObject()) {
+            const js_obj = js_val.toObject();
+            if (js_obj.has("stack")) {
+                js_val = js_obj.get("stack") catch break :blk null;
+            }
+        }
+
+        if (js_val.isString()) |js_str| {
+            break :blk js_str.toSliceWithAlloc(allocator) catch |err| @errorName(err);
+        }
+        break :blk null;
     };
 
     return .{

src/browser/js/Value.zig

@@ -18,6 +18,7 @@
 
 const std = @import("std");
 const js = @import("js.zig");
+const SSO = @import("../../string.zig").String;
 
 const v8 = js.v8;
 
@@ -34,8 +35,12 @@ pub fn isObject(self: Value) bool {
     return v8.v8__Value__IsObject(self.handle);
 }
 
-pub fn isString(self: Value) bool {
-    return v8.v8__Value__IsString(self.handle);
+pub fn isString(self: Value) ?js.String {
+    const handle = self.handle;
+    if (!v8.v8__Value__IsString(handle)) {
+        return null;
+    }
+    return .{ .local = self.local, .handle = @ptrCast(handle) };
 }
 
 pub fn isArray(self: Value) bool {
@@ -204,35 +209,40 @@ pub fn toPromise(self: Value) js.Promise {
     };
 }
 
-pub fn toString(self: Value, opts: js.String.ToZigOpts) ![]u8 {
-    return self._toString(false, opts);
+pub fn toString(self: Value) !js.String {
+    const l = self.local;
+    const value_handle: *const v8.Value = blk: {
+        if (self.isSymbol()) {
+            break :blk @ptrCast(v8.v8__Symbol__Description(@ptrCast(self.handle), l.isolate.handle).?);
+        }
+        break :blk self.handle;
+    };
+
+    const str_handle = v8.v8__Value__ToString(value_handle, l.handle) orelse return error.JsException;
+    return .{ .local = self.local, .handle = str_handle };
 }
-pub fn toStringZ(self: Value, opts: js.String.ToZigOpts) ![:0]u8 {
-    return self._toString(true, opts);
+
+pub fn toSSO(self: Value, comptime global: bool) !(if (global) SSO.Global else SSO) {
+    return (try self.toString()).toSSO(global);
+}
+pub fn toSSOWithAlloc(self: Value, allocator: Allocator) !SSO {
+    return (try self.toString()).toSSOWithAlloc(allocator);
+}
+
+pub fn toStringSlice(self: Value) ![]u8 {
+    return (try self.toString()).toSlice();
+}
+pub fn toStringSliceZ(self: Value) ![:0]u8 {
+    return (try self.toString()).toSliceZ();
+}
+pub fn toStringSliceWithAlloc(self: Value, allocator: Allocator) ![]u8 {
+    return (try self.toString()).toSliceWithAlloc(allocator);
 }
 
 pub fn toJson(self: Value, allocator: Allocator) ![]u8 {
-    const json_str_handle = v8.v8__JSON__Stringify(self.local.handle, self.handle, null) orelse return error.JsException;
-    return self.local.jsStringToZig(json_str_handle, .{ .allocator = allocator });
-}
-
-fn _toString(self: Value, comptime null_terminate: bool, opts: js.String.ToZigOpts) !(if (null_terminate) [:0]u8 else []u8) {
-    const l = self.local;
-
-    if (self.isSymbol()) {
-        const sym_handle = v8.v8__Symbol__Description(@ptrCast(self.handle), l.isolate.handle).?;
-        return _toString(.{ .handle = @ptrCast(sym_handle), .local = l }, null_terminate, opts);
-    }
-
-    const str_handle = v8.v8__Value__ToString(self.handle, l.handle) orelse {
-        return error.JsException;
-    };
-
-    const str = js.String{ .local = l, .handle = str_handle };
-    if (comptime null_terminate) {
-        return js.String.toZigZ(str, opts);
-    }
-    return js.String.toZig(str, opts);
+    const local = self.local;
+    const str_handle = v8.v8__JSON__Stringify(local.handle, self.handle, null) orelse return error.JsException;
+    return js.String.toSliceWithAlloc(.{ .local = local, .handle = str_handle }, allocator);
 }
 
 pub fn persist(self: Value) !Global {
@@ -296,8 +306,8 @@ pub fn format(self: Value, writer: *std.Io.Writer) !void {
     if (comptime IS_DEBUG) {
         return self.local.debugValue(self, writer);
     }
-    const str = self.toString(.{}) catch return error.WriteFailed;
-    return writer.writeAll(str);
+    const js_str = self.toString() catch return error.WriteFailed;
+    return js_str.format(writer);
 }
 
 pub const Temp = G(0);

src/browser/js/bridge.zig

@@ -38,11 +38,11 @@ pub fn Builder(comptime T: type) type {
             return Constructor.init(T, func, opts);
         }
 
-        pub fn accessor(comptime getter: anytype, comptime setter: anytype, comptime opts: Accessor.Opts) Accessor {
+        pub fn accessor(comptime getter: anytype, comptime setter: anytype, comptime opts: Caller.Function.Opts) Accessor {
             return Accessor.init(T, getter, setter, opts);
         }
 
-        pub fn function(comptime func: anytype, comptime opts: Function.Opts) Function {
+        pub fn function(comptime func: anytype, comptime opts: Caller.Function.Opts) Function {
             return Function.init(T, func, opts);
         }
 
@@ -62,9 +62,21 @@ pub fn Builder(comptime T: type) type {
             return Callable.init(T, func, opts);
         }
 
-        pub fn property(value: anytype) Property {
+        pub fn property(value: anytype, opts: Property.Opts) Property {
             switch (@typeInfo(@TypeOf(value))) {
-                .comptime_int, .int => return .{ .int = value },
+                .bool => return Property.init(.{ .bool = value }, opts),
+                .null => return Property.init(.null, opts),
+                .comptime_int, .int => return Property.init(.{ .int = value }, opts),
+                .comptime_float, .float => return Property.init(.{ .float = value }, opts),
+                .pointer => |ptr| switch (ptr.size) {
+                    .one => {
+                        const one_info = @typeInfo(ptr.child);
+                        if (one_info == .array and one_info.array.child == u8) {
+                            return Property.init(.{ .string = value }, opts);
+                        }
+                    },
+                    else => {},
+                },
                 else => {},
             }
             @compileError("Property for " ++ @typeName(@TypeOf(value)) ++ " hasn't been defined yet");
@@ -103,20 +115,18 @@ pub fn Builder(comptime T: type) type {
                 .from_v8 = struct {
                     fn wrap(handle: ?*const v8.WeakCallbackInfo) callconv(.c) void {
                         const ptr = v8.v8__WeakCallbackInfo__GetParameter(handle.?).?;
-                        const self: *T = @ptrCast(@alignCast(ptr));
-                        // This is simply a requirement of any type that Finalizes:
-                        // It must have a _page: *Page field. We need it because
-                        // we need to check the item has already been cleared
-                        // (There are all types of weird timing issues that seem
-                        // to be possible between finalization and context shutdown,
-                        // we need to be defensive).
-                        // There _ARE_ alternatives to this. But this is simple.
-                        const ctx = self._page.js;
-                        if (!ctx.identity_map.contains(@intFromPtr(ptr))) {
-                            return;
+                        const fc: *Context.FinalizerCallback = @ptrCast(@alignCast(ptr));
+
+                        const ctx = fc.ctx;
+                        const value_ptr = fc.ptr;
+                        if (ctx.finalizer_callbacks.contains(@intFromPtr(value_ptr))) {
+                            func(@ptrCast(@alignCast(value_ptr)), false);
+                            ctx.release(value_ptr);
+                        } else {
+                            // A bit weird, but v8 _requires_ that we release it
+                            // If we don't. We'll 100% crash.
+                            v8.v8__Global__Reset(&fc.global);
                         }
-                        func(self, false);
-                        ctx.release(ptr);
                     }
                 }.wrap,
             };
@@ -149,82 +159,56 @@ pub const Constructor = struct {
 
 pub const Function = struct {
     static: bool,
+    arity: usize,
+    cache: ?Caller.Function.Opts.Caching = null,
     func: *const fn (?*const v8.FunctionCallbackInfo) callconv(.c) void,
 
-    const Opts = struct {
-        static: bool = false,
-        dom_exception: bool = false,
-        as_typed_array: bool = false,
-        null_as_undefined: bool = false,
-    };
-
-    fn init(comptime T: type, comptime func: anytype, comptime opts: Opts) Function {
+    fn init(comptime T: type, comptime func: anytype, comptime opts: Caller.Function.Opts) Function {
         return .{
+            .cache = opts.cache,
             .static = opts.static,
+            .arity = getArity(@TypeOf(func)),
             .func = struct {
                 fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-                    const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
-                    var caller: Caller = undefined;
-                    caller.init(v8_isolate);
-                    defer caller.deinit();
-
-                    if (comptime opts.static) {
-                        caller.function(T, func, handle.?, .{
-                            .dom_exception = opts.dom_exception,
-                            .as_typed_array = opts.as_typed_array,
-                            .null_as_undefined = opts.null_as_undefined,
-                        });
-                    } else {
-                        caller.method(T, func, handle.?, .{
-                            .dom_exception = opts.dom_exception,
-                            .as_typed_array = opts.as_typed_array,
-                            .null_as_undefined = opts.null_as_undefined,
-                        });
-                    }
+                    Caller.Function.call(T, handle.?, func, opts);
                 }
             }.wrap,
         };
     }
+
+    fn getArity(comptime T: type) usize {
+        var count: usize = 0;
+        var params = @typeInfo(T).@"fn".params;
+        for (params[1..]) |p| { // start at 1, skip self
+            const PT = p.type.?;
+            if (PT == *Page or PT == *const Page) {
+                break;
+            }
+            if (@typeInfo(PT) == .optional) {
+                break;
+            }
+            count += 1;
+        }
+        return count;
+    }
 };
 
 pub const Accessor = struct {
     static: bool = false,
+    cache: ?Caller.Function.Opts.Caching = null,
     getter: ?*const fn (?*const v8.FunctionCallbackInfo) callconv(.c) void = null,
     setter: ?*const fn (?*const v8.FunctionCallbackInfo) callconv(.c) void = null,
 
-    const Opts = struct {
-        static: bool = false,
-        cache: ?[]const u8 = null,
-        as_typed_array: bool = false,
-        null_as_undefined: bool = false,
-    };
-
-    fn init(comptime T: type, comptime getter: anytype, comptime setter: anytype, comptime opts: Opts) Accessor {
+    fn init(comptime T: type, comptime getter: anytype, comptime setter: anytype, comptime opts: Caller.Function.Opts) Accessor {
         var accessor = Accessor{
+            .cache = opts.cache,
             .static = opts.static,
         };
 
         if (@typeInfo(@TypeOf(getter)) != .null) {
             accessor.getter = struct {
                 fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-                    const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
-                    var caller: Caller = undefined;
-                    caller.init(v8_isolate);
-                    defer caller.deinit();
-
-                    if (comptime opts.static) {
-                        caller.function(T, getter, handle.?, .{
-                            .cache = opts.cache,
-                            .as_typed_array = opts.as_typed_array,
-                            .null_as_undefined = opts.null_as_undefined,
-                        });
-                    } else {
-                        caller.method(T, getter, handle.?, .{
-                            .cache = opts.cache,
-                            .as_typed_array = opts.as_typed_array,
-                            .null_as_undefined = opts.null_as_undefined,
-                        });
-                    }
+                    Caller.Function.call(T, handle.?, getter, opts);
                 }
             }.wrap;
         }
@@ -232,15 +216,7 @@ pub const Accessor = struct {
         if (@typeInfo(@TypeOf(setter)) != .null) {
             accessor.setter = struct {
                 fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-                    const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
-                    var caller: Caller = undefined;
-                    caller.init(v8_isolate);
-                    defer caller.deinit();
-
-                    caller.method(T, setter, handle.?, .{
-                        .as_typed_array = opts.as_typed_array,
-                        .null_as_undefined = opts.null_as_undefined,
-                    });
+                    Caller.Function.call(T, handle.?, setter, opts);
                 }
             }.wrap;
         }
@@ -361,11 +337,9 @@ pub const Iterator = struct {
             .async = opts.async,
             .func = struct {
                 fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-                    const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
-                    var caller: Caller = undefined;
-                    caller.init(v8_isolate);
-                    defer caller.deinit();
-                    caller.method(T, struct_or_func, handle.?, .{});
+                    return Caller.Function.call(T, handle.?, struct_or_func, .{
+                        .null_as_undefined = opts.null_as_undefined,
+                    });
                 }
             }.wrap,
         };
@@ -382,12 +356,7 @@ pub const Callable = struct {
     fn init(comptime T: type, comptime func: anytype, comptime opts: Opts) Callable {
         return .{ .func = struct {
             fn wrap(handle: ?*const v8.FunctionCallbackInfo) callconv(.c) void {
-                const v8_isolate = v8.v8__FunctionCallbackInfo__GetIsolate(handle).?;
-                var caller: Caller = undefined;
-                caller.init(v8_isolate);
-                defer caller.deinit();
-
-                caller.method(T, func, handle.?, .{
+                Caller.Function.call(T, handle.?, func, .{
                     .null_as_undefined = opts.null_as_undefined,
                 });
             }
@@ -395,8 +364,35 @@ pub const Callable = struct {
     }
 };
 
-pub const Property = union(enum) {
-    int: i64,
+pub const Property = struct {
+    value: Value,
+    template: bool,
+
+    const Value = union(enum) {
+        null,
+        int: i64,
+        float: f64,
+        bool: bool,
+        string: []const u8,
+    };
+
+    const Opts = struct {
+        template: bool,
+    };
+
+    fn init(value: Value, opts: Opts) Property {
+        return .{
+            .value = value,
+            .template = opts.template,
+        };
+    }
+
+    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 {
@@ -410,7 +406,7 @@ const Finalizer = struct {
     from_v8: *const fn (?*const v8.WeakCallbackInfo) callconv(.c) void,
 };
 
-pub fn unknownPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
+pub fn unknownWindowPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
     const v8_isolate = v8.v8__PropertyCallbackInfo__GetIsolate(handle).?;
     var caller: Caller = undefined;
     caller.init(v8_isolate);
@@ -422,7 +418,7 @@ pub fn unknownPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.Prope
     hs.init(local.isolate);
     defer hs.deinit();
 
-    const property: []const u8 = local.valueHandleToString(@ptrCast(c_name.?), .{}) catch {
+    const property: []const u8 = js.String.toSlice(.{ .local = local, .handle = @ptrCast(c_name.?) }) catch {
         return 0;
     };
 
@@ -437,11 +433,21 @@ pub fn unknownPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.Prope
     }
 
     if (comptime IS_DEBUG) {
+        if (std.mem.startsWith(u8, property, "__")) {
+            // some frameworks will extend built-in types using a __ prefix
+            // these should always be safe to ignore.
+            return 0;
+        }
+
         const ignored = std.StaticStringMap(void).initComptime(.{
+            .{ "Deno", {} },
             .{ "process", {} },
             .{ "ShadyDOM", {} },
             .{ "ShadyCSS", {} },
 
+            // a lot of sites seem to like having their own window.config.
+            .{ "config", {} },
+
             .{ "litNonce", {} },
             .{ "litHtmlVersions", {} },
             .{ "litElementVersions", {} },
@@ -457,13 +463,12 @@ pub fn unknownPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.Prope
             .{ "__google_recaptcha_client", {} },
 
             .{ "CLOSURE_FLAGS", {} },
+            .{ "__REACT_DEVTOOLS_GLOBAL_HOOK__", {} },
+            .{ "ApplePaySession", {} },
         });
         if (!ignored.has(property)) {
-            log.debug(.unknown_prop, "unknown global property", .{
-                .info = "but the property can exist in pure JS",
-                .stack = local.stackTrace() catch "???",
-                .property = property,
-            });
+            const key = std.fmt.bufPrint(&local.ctx.page.buf, "Window:{s}", .{property}) catch return 0;
+            logUnknownProperty(local, key) catch return 0;
         }
     }
 
@@ -471,6 +476,83 @@ pub fn unknownPropertyCallback(c_name: ?*const v8.Name, handle: ?*const v8.Prope
     return 0;
 }
 
+// Only used for debugging
+pub fn unknownObjectPropertyCallback(comptime JsApi: type) *const fn (?*const v8.Name, ?*const v8.PropertyCallbackInfo) callconv(.c) u8 {
+    if (comptime !IS_DEBUG) {
+        @compileError("unknownObjectPropertyCallback should only be used in debug builds");
+    }
+
+    return struct {
+        fn wrap(c_name: ?*const v8.Name, 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();
+
+            const local = &caller.local;
+
+            var hs: js.HandleScope = undefined;
+            hs.init(local.isolate);
+            defer hs.deinit();
+
+            const property: []const u8 = js.String.toSlice(.{ .local = local, .handle = @ptrCast(c_name.?) }) catch {
+                return 0;
+            };
+
+            if (std.mem.startsWith(u8, property, "__")) {
+                // some frameworks will extend built-in types using a __ prefix
+                // these should always be safe to ignore.
+                return 0;
+            }
+
+            if (std.mem.startsWith(u8, property, "jQuery")) {
+                return 0;
+            }
+
+            if (JsApi == @import("../webapi/cdata/Text.zig").JsApi or JsApi == @import("../webapi/cdata/Comment.zig").JsApi) {
+                if (std.mem.eql(u8, property, "tagName")) {
+                    // knockout does this, a lot.
+                    return 0;
+                }
+            }
+
+            if (JsApi == @import("../webapi/element/Html.zig").JsApi or JsApi == @import("../webapi/Element.zig").JsApi or JsApi == @import("../webapi/element/html/Custom.zig").JsApi) {
+                // react ?
+                if (std.mem.eql(u8, property, "props")) return 0;
+                if (std.mem.eql(u8, property, "hydrated")) return 0;
+                if (std.mem.eql(u8, property, "isHydrated")) return 0;
+            }
+
+            if (JsApi == @import("../webapi/Console.zig").JsApi) {
+                if (std.mem.eql(u8, property, "firebug")) return 0;
+            }
+
+            const ignored = std.StaticStringMap(void).initComptime(.{});
+            if (!ignored.has(property)) {
+                const key = std.fmt.bufPrint(&local.ctx.page.buf, "{s}:{s}", .{ if (@hasDecl(JsApi.Meta, "name")) JsApi.Meta.name else @typeName(JsApi), property }) catch return 0;
+                logUnknownProperty(local, key) catch return 0;
+            }
+            // not intercepted
+            return 0;
+        }
+    }.wrap;
+}
+
+fn logUnknownProperty(local: *const js.Local, key: []const u8) !void {
+    const ctx = local.ctx;
+    const gop = try ctx.unknown_properties.getOrPut(ctx.arena, key);
+    if (gop.found_existing) {
+        gop.value_ptr.count += 1;
+    } else {
+        gop.key_ptr.* = try ctx.arena.dupe(u8, key);
+        gop.value_ptr.* = .{
+            .count = 1,
+            .first_stack = try ctx.arena.dupe(u8, (try local.stackTrace()) orelse "???"),
+        };
+    }
+}
+
 // Given a Type, returns the length of the prototype chain, including self
 fn prototypeChainLength(comptime T: type) usize {
     var l: usize = 1;
@@ -669,6 +751,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/element/html/DataList.zig"),
     @import("../webapi/element/html/Dialog.zig"),
     @import("../webapi/element/html/Directory.zig"),
+    @import("../webapi/element/html/DList.zig"),
     @import("../webapi/element/html/Div.zig"),
     @import("../webapi/element/html/Embed.zig"),
     @import("../webapi/element/html/FieldSet.zig"),
@@ -696,6 +779,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/element/html/Option.zig"),
     @import("../webapi/element/html/Output.zig"),
     @import("../webapi/element/html/Paragraph.zig"),
+    @import("../webapi/element/html/Picture.zig"),
     @import("../webapi/element/html/Param.zig"),
     @import("../webapi/element/html/Pre.zig"),
     @import("../webapi/element/html/Progress.zig"),
@@ -737,6 +821,10 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/event/MouseEvent.zig"),
     @import("../webapi/event/PointerEvent.zig"),
     @import("../webapi/event/KeyboardEvent.zig"),
+    @import("../webapi/event/FocusEvent.zig"),
+    @import("../webapi/event/WheelEvent.zig"),
+    @import("../webapi/event/TextEvent.zig"),
+    @import("../webapi/event/PromiseRejectionEvent.zig"),
     @import("../webapi/MessageChannel.zig"),
     @import("../webapi/MessagePort.zig"),
     @import("../webapi/media/MediaError.zig"),
@@ -761,6 +849,7 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/URL.zig"),
     @import("../webapi/Window.zig"),
     @import("../webapi/Performance.zig"),
+    @import("../webapi/PluginArray.zig"),
     @import("../webapi/MutationObserver.zig"),
     @import("../webapi/IntersectionObserver.zig"),
     @import("../webapi/CustomElementRegistry.zig"),
@@ -769,13 +858,14 @@ pub const JsApis = flattenTypes(&.{
     @import("../webapi/Blob.zig"),
     @import("../webapi/File.zig"),
     @import("../webapi/Screen.zig"),
+    @import("../webapi/VisualViewport.zig"),
     @import("../webapi/PerformanceObserver.zig"),
     @import("../webapi/navigation/Navigation.zig"),
-    @import("../webapi/navigation/NavigationEventTarget.zig"),
     @import("../webapi/navigation/NavigationHistoryEntry.zig"),
     @import("../webapi/navigation/NavigationActivation.zig"),
     @import("../webapi/canvas/CanvasRenderingContext2D.zig"),
     @import("../webapi/canvas/WebGLRenderingContext.zig"),
     @import("../webapi/SubtleCrypto.zig"),
     @import("../webapi/Selection.zig"),
+    @import("../webapi/ImageData.zig"),
 });

src/browser/js/js.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -19,12 +19,10 @@
 const std = @import("std");
 pub const v8 = @import("v8").c;
 
-const log = @import("../../log.zig");
 const string = @import("../../string.zig");
 
 pub const Env = @import("Env.zig");
 pub const bridge = @import("bridge.zig");
-pub const ExecutionWorld = @import("ExecutionWorld.zig");
 pub const Caller = @import("Caller.zig");
 pub const Context = @import("Context.zig");
 pub const Local = @import("Local.zig");
@@ -34,7 +32,6 @@ pub const Platform = @import("Platform.zig");
 pub const Isolate = @import("Isolate.zig");
 pub const HandleScope = @import("HandleScope.zig");
 
-pub const Name = @import("Name.zig");
 pub const Value = @import("Value.zig");
 pub const Array = @import("Array.zig");
 pub const String = @import("String.zig");
@@ -47,6 +44,7 @@ pub const BigInt = @import("BigInt.zig");
 pub const Number = @import("Number.zig");
 pub const Integer = @import("Integer.zig");
 pub const PromiseResolver = @import("PromiseResolver.zig");
+pub const PromiseRejection = @import("PromiseRejection.zig");
 
 const Allocator = std.mem.Allocator;
 
@@ -79,6 +77,97 @@ pub const ArrayBuffer = struct {
     }
 };
 
+pub const ArrayType = enum(u8) {
+    int8,
+    uint8,
+    uint8_clamped,
+    int16,
+    uint16,
+    int32,
+    uint32,
+    float16,
+    float32,
+    float64,
+};
+
+pub fn ArrayBufferRef(comptime kind: ArrayType) type {
+    return struct {
+        const Self = @This();
+
+        const BackingInt = switch (kind) {
+            .int8 => i8,
+            .uint8, .uint8_clamped => u8,
+            .int16 => i16,
+            .uint16 => u16,
+            .int32 => i32,
+            .uint32 => u32,
+            .float16 => f16,
+            .float32 => f32,
+            .float64 => f64,
+        };
+
+        local: *const Local,
+        handle: *const v8.Value,
+
+        /// Persisted typed array.
+        pub const Global = struct {
+            handle: v8.Global,
+
+            pub fn deinit(self: *Global) void {
+                v8.v8__Global__Reset(&self.handle);
+            }
+
+            pub fn local(self: *const Global, l: *const Local) Self {
+                return .{ .local = l, .handle = v8.v8__Global__Get(&self.handle, l.isolate.handle).? };
+            }
+        };
+
+        pub fn init(local: *const Local, size: usize) Self {
+            const ctx = local.ctx;
+            const isolate = ctx.isolate;
+            const bits = switch (@typeInfo(BackingInt)) {
+                .int => |n| n.bits,
+                .float => |f| f.bits,
+                else => unreachable,
+            };
+
+            var array_buffer: *const v8.ArrayBuffer = undefined;
+            if (size == 0) {
+                array_buffer = v8.v8__ArrayBuffer__New(isolate.handle, 0).?;
+            } else {
+                const buffer_len = size * bits / 8;
+                const backing_store = v8.v8__ArrayBuffer__NewBackingStore(isolate.handle, buffer_len).?;
+                const backing_store_ptr = v8.v8__BackingStore__TO_SHARED_PTR(backing_store);
+                array_buffer = v8.v8__ArrayBuffer__New2(isolate.handle, &backing_store_ptr).?;
+            }
+
+            const handle: *const v8.Value = switch (comptime kind) {
+                .int8 => @ptrCast(v8.v8__Int8Array__New(array_buffer, 0, size).?),
+                .uint8 => @ptrCast(v8.v8__Uint8Array__New(array_buffer, 0, size).?),
+                .uint8_clamped => @ptrCast(v8.v8__Uint8ClampedArray__New(array_buffer, 0, size).?),
+                .int16 => @ptrCast(v8.v8__Int16Array__New(array_buffer, 0, size).?),
+                .uint16 => @ptrCast(v8.v8__Uint16Array__New(array_buffer, 0, size).?),
+                .int32 => @ptrCast(v8.v8__Int32Array__New(array_buffer, 0, size).?),
+                .uint32 => @ptrCast(v8.v8__Uint32Array__New(array_buffer, 0, size).?),
+                .float16 => @ptrCast(v8.v8__Float16Array__New(array_buffer, 0, size).?),
+                .float32 => @ptrCast(v8.v8__Float32Array__New(array_buffer, 0, size).?),
+                .float64 => @ptrCast(v8.v8__Float64Array__New(array_buffer, 0, size).?),
+            };
+
+            return .{ .local = local, .handle = handle };
+        }
+
+        pub fn persist(self: *const Self) !Global {
+            var ctx = self.local.ctx;
+            var global: v8.Global = undefined;
+            v8.v8__Global__New(ctx.isolate.handle, self.handle, &global);
+            try ctx.global_values.append(ctx.arena, global);
+
+            return .{ .handle = global };
+        }
+    };
+}
+
 pub const Exception = struct {
     local: *const Local,
     handle: *const v8.Value,
@@ -136,8 +225,10 @@ pub fn simpleZigValueToJs(isolate: Isolate, value: anytype, comptime fail: bool,
                     const values = value.values;
                     const len = values.len;
                     const backing_store = v8.v8__ArrayBuffer__NewBackingStore(isolate.handle, len);
-                    const data: [*]u8 = @ptrCast(@alignCast(v8.v8__BackingStore__Data(backing_store)));
-                    @memcpy(data[0..len], @as([]const u8, @ptrCast(values))[0..len]);
+                    if (len > 0) {
+                        const data: [*]u8 = @ptrCast(@alignCast(v8.v8__BackingStore__Data(backing_store)));
+                        @memcpy(data[0..len], @as([]const u8, @ptrCast(values))[0..len]);
+                    }
                     const backing_store_ptr = v8.v8__BackingStore__TO_SHARED_PTR(backing_store);
                     return @ptrCast(v8.v8__ArrayBuffer__New2(isolate.handle, &backing_store_ptr).?);
                 },

src/browser/markdown.zig

@@ -0,0 +1,506 @@
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
+//
+// Francis Bouvier <francis@lightpanda.io>
+// Pierre Tachoire <pierre@lightpanda.io>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+const std = @import("std");
+
+const Page = @import("Page.zig");
+const Element = @import("webapi/Element.zig");
+const Node = @import("webapi/Node.zig");
+
+pub const Opts = struct {
+    // Options for future customization (e.g., dialect)
+};
+
+const State = struct {
+    const ListType = enum { ordered, unordered };
+    const ListState = struct {
+        type: ListType,
+        index: usize,
+    };
+
+    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,
+    table_row_index: usize = 0,
+    table_col_count: usize = 0,
+    last_char_was_newline: bool = true,
+};
+
+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,
+        else => false,
+    };
+}
+
+fn shouldAddSpacing(tag: Element.Tag) bool {
+    return switch (tag) {
+        .p, .h1, .h2, .h3, .h4, .h5, .h6, .blockquote, .pre, .table => true,
+        else => false,
+    };
+}
+
+fn ensureNewline(state: *State, writer: *std.Io.Writer) !void {
+    if (!state.last_char_was_newline) {
+        try writer.writeByte('\n');
+        state.last_char_was_newline = true;
+    }
+}
+
+pub fn dump(node: *Node, opts: Opts, writer: *std.Io.Writer, page: *Page) !void {
+    _ = opts;
+    var state = State{};
+    try render(node, &state, writer, page);
+    if (!state.last_char_was_newline) {
+        try writer.writeByte('\n');
+    }
+}
+
+fn render(node: *Node, state: *State, writer: *std.Io.Writer, page: *Page) error{WriteFailed}!void {
+    switch (node._type) {
+        .document, .document_fragment => {
+            try renderChildren(node, state, writer, page);
+        },
+        .element => |el| {
+            try renderElement(el, state, writer, page);
+        },
+        .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");
+                        }
+                    }
+                }
+                try renderText(text, state, writer);
+            }
+        },
+        else => {}, // Ignore other node types
+    }
+}
+
+fn renderChildren(parent: *Node, state: *State, writer: *std.Io.Writer, page: *Page) !void {
+    var it = parent.childrenIterator();
+    while (it.next()) |child| {
+        try render(child, state, writer, page);
+    }
+}
+
+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 => {},
+    }
+
+    // --- 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');
+            }
+        }
+    } else if (tag == .li or tag == .tr) {
+        try ensureNewline(state, writer);
+    }
+
+    // Prefixes
+    switch (tag) {
+        .h1 => try writer.writeAll("# "),
+        .h2 => try writer.writeAll("## "),
+        .h3 => try writer.writeAll("### "),
+        .h4 => try writer.writeAll("#### "),
+        .h5 => try writer.writeAll("##### "),
+        .h6 => try writer.writeAll("###### "),
+        .ul => {
+            if (state.list_depth < state.list_stack.len) {
+                state.list_stack[state.list_depth] = .{ .type = .unordered, .index = 0 };
+                state.list_depth += 1;
+            }
+        },
+        .ol => {
+            if (state.list_depth < state.list_stack.len) {
+                state.list_stack[state.list_depth] = .{ .type = .ordered, .index = 1 };
+                state.list_depth += 1;
+            }
+        },
+        .li => {
+            const indent = if (state.list_depth > 0) state.list_depth - 1 else 0;
+            for (0..indent) |_| try writer.writeAll("  ");
+
+            if (state.list_depth > 0) {
+                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("- ");
+                }
+            } else {
+                try writer.writeAll("- ");
+            }
+            state.last_char_was_newline = false;
+        },
+        .table => {
+            state.in_table = true;
+            state.table_row_index = 0;
+            state.table_col_count = 0;
+        },
+        .tr => {
+            state.table_col_count = 0;
+            try writer.writeByte('|');
+        },
+        .td, .th => {
+            // Note: leading pipe handled by previous cell closing or tr opening
+            state.last_char_was_newline = false;
+            try writer.writeByte(' ');
+        },
+        .blockquote => {
+            try writer.writeAll("> ");
+            state.last_char_was_newline = false;
+        },
+        .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) {
+                try writer.writeByte('`');
+                state.in_code = true;
+                state.last_char_was_newline = false;
+            }
+        },
+        .b, .strong => {
+            try writer.writeAll("**");
+            state.last_char_was_newline = false;
+        },
+        .i, .em => {
+            try writer.writeAll("*");
+            state.last_char_was_newline = false;
+        },
+        .s, .del => {
+            try writer.writeAll("~~");
+            state.last_char_was_newline = false;
+        },
+        .hr => {
+            try writer.writeAll("---\n");
+            state.last_char_was_newline = true;
+            return; // Void element
+        },
+        .br => {
+            if (state.in_table) {
+                try writer.writeByte(' ');
+            } else {
+                try writer.writeByte('\n');
+                state.last_char_was_newline = true;
+            }
+            return; // Void element
+        },
+        .img => {
+            try writer.writeAll("![");
+            if (el.getAttributeSafe(comptime .wrap("alt"))) |alt| {
+                try escapeMarkdown(writer, alt);
+            }
+            try writer.writeAll("](");
+            if (el.getAttributeSafe(comptime .wrap("src"))) |src| {
+                try writer.writeAll(src);
+            }
+            try writer.writeAll(")");
+            state.last_char_was_newline = false;
+            return; // Treat as void
+        },
+        .anchor => {
+            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.writeByte(')');
+            state.last_char_was_newline = false;
+            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;
+                }
+            }
+            return;
+        },
+        else => {},
+    }
+
+    // --- Render Children ---
+    try renderChildren(el.asNode(), state, writer, page);
+
+    // --- Closing Tag Logic ---
+
+    // Suffixes
+    switch (tag) {
+        .pre => {
+            if (!state.last_char_was_newline) {
+                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) {
+                try writer.writeByte('`');
+                state.in_code = false;
+                state.last_char_was_newline = false;
+            }
+        },
+        .b, .strong => {
+            try writer.writeAll("**");
+            state.last_char_was_newline = false;
+        },
+        .i, .em => {
+            try writer.writeAll("*");
+            state.last_char_was_newline = false;
+        },
+        .s, .del => {
+            try writer.writeAll("~~");
+            state.last_char_was_newline = false;
+        },
+        .blockquote => {},
+        .ul, .ol => {
+            if (state.list_depth > 0) state.list_depth -= 1;
+        },
+        .table => {
+            state.in_table = false;
+        },
+        .tr => {
+            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) {
+                    try writer.writeAll("---|");
+                }
+                try writer.writeByte('\n');
+            }
+            state.table_row_index += 1;
+            state.last_char_was_newline = true;
+        },
+        .td, .th => {
+            try writer.writeAll(" |");
+            state.table_col_count += 1;
+            state.last_char_was_newline = false;
+        },
+        else => {},
+    }
+
+    // Post-block newlines
+    if (isBlock(tag)) {
+        if (!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) {
+        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;
+        }
+        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 (!state.last_char_was_newline) {
+            try writer.writeByte(' ');
+        }
+        return;
+    }
+
+    // Collapse whitespace
+    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 {
+            try writer.writeByte(' ');
+        }
+
+        try escapeMarkdown(writer, word);
+        state.last_char_was_newline = false;
+        first = false;
+    }
+
+    // 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(' ');
+        }
+    }
+}
+
+fn escapeMarkdown(writer: *std.Io.Writer, text: []const u8) !void {
+    for (text) |c| {
+        switch (c) {
+            '\\', '`', '*', '_', '{', '}', '[', ']', '(', ')', '#', '+', '-', '!', '|' => {
+                try writer.writeByte('\\');
+                try writer.writeByte(c);
+            },
+            else => try writer.writeByte(c),
+        }
+    }
+}
+
+fn testMarkdownHTML(html: []const u8, expected: []const u8) !void {
+    const testing = @import("../testing.zig");
+    const page = try testing.test_session.createPage();
+    defer testing.test_session.removePage();
+    const doc = page.window._document;
+
+    const div = try doc.createElement("div", null, page);
+    try page.parseHtmlAsChildren(div.asNode(), html);
+
+    var aw: std.Io.Writer.Allocating = .init(testing.allocator);
+    defer aw.deinit();
+    try dump(div.asNode(), .{}, &aw.writer, page);
+
+    try testing.expectString(expected, aw.written());
+}
+
+test "markdown: basic" {
+    try testMarkdownHTML("Hello world", "Hello world\n");
+}
+
+test "markdown: whitespace" {
+    try testMarkdownHTML("<span>A</span> <span>B</span>", "A B\n");
+}
+
+test "markdown: escaping" {
+    try testMarkdownHTML("<p># Not a header</p>", "\n\\# Not a header\n");
+}
+
+test "markdown: strikethrough" {
+    try testMarkdownHTML("<s>deleted</s>", "~~deleted~~\n");
+}
+
+test "markdown: task list" {
+    try testMarkdownHTML(
+        \\<input type="checkbox" checked><input type="checkbox">
+    , "[x] [ ] \n");
+}
+
+test "markdown: ordered list" {
+    try testMarkdownHTML(
+        \\<ol><li>First</li><li>Second</li></ol>
+    , "1. First\n2. Second\n");
+}
+
+test "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>
+    ,
+        \\
+        \\| Head 1 | Head 2 |
+        \\|---|---|
+        \\| Cell 1 | Cell 2 |
+        \\
+    );
+}
+
+test "markdown: nested lists" {
+    try testMarkdownHTML(
+        \\<ul><li>Parent<ul><li>Child</li></ul></li></ul>
+    ,
+        \\- Parent
+        \\  - Child
+        \\
+    );
+}
+
+test "markdown: blockquote" {
+    try testMarkdownHTML("<blockquote>Hello world</blockquote>", "\n> Hello world\n");
+}
+
+test "markdown: links" {
+    try testMarkdownHTML("<a href=\"https://lightpanda.io\">Lightpanda</a>", "[Lightpanda](https://lightpanda.io)\n");
+}
+
+test "markdown: images" {
+    try testMarkdownHTML("<img src=\"logo.png\" alt=\"Logo\">", "![Logo](logo.png)\n");
+}
+
+test "markdown: headings" {
+    try testMarkdownHTML("<h1>Title</h1><h2>Subtitle</h2>",
+        \\
+        \\# Title
+        \\
+        \\## Subtitle
+        \\
+    );
+}
+
+test "markdown: code" {
+    try testMarkdownHTML(
+        \\<p>Use git push</p>
+        \\<pre><code>line 1
+        \\line 2</code></pre>
+    ,
+        \\
+        \\Use git push
+        \\
+        \\```
+        \\line 1
+        \\line 2
+        \\```
+        \\
+    );
+}

src/browser/parser/Parser.zig

@@ -421,7 +421,16 @@ fn appendBeforeSiblingCallback(ctx: *anyopaque, sibling_ref: *anyopaque, node_or
 fn _appendBeforeSiblingCallback(self: *Parser, sibling: *Node, node_or_text: h5e.NodeOrText) !void {
     const parent = sibling.parentNode() orelse return error.NoParent;
     const node: *Node = switch (node_or_text.toUnion()) {
-        .node => |cpn| getNode(cpn),
+        .node => |cpn| blk: {
+            const child = getNode(cpn);
+            if (child._parent) |previous_parent| {
+                // A custom element constructor may have inserted the node into the
+                // DOM before the parser officially places it (e.g. via foster
+                // parenting). Detach it first so insertNodeRelative's assertion holds.
+                self.page.removeNode(previous_parent, child, .{ .will_be_reconnected = parent.isConnected() });
+            }
+            break :blk child;
+        },
         .text => |txt| try self.page.createTextNode(txt),
     };
     try self.page.insertNodeRelative(parent, node, .{ .before = sibling }, .{});

src/browser/reflect.zig

@@ -1,4 +1,4 @@
-// Copyright (C) 2023-2025  Lightpanda (Selecy SAS)
+// Copyright (C) 2023-2026  Lightpanda (Selecy SAS)
 //
 // Francis Bouvier <francis@lightpanda.io>
 // Pierre Tachoire <pierre@lightpanda.io>
@@ -16,8 +16,6 @@
 // You should have received a copy of the GNU Affero General Public License
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
-const std = @import("std");
-
 // Gets the Parent of child.
 // HtmlElement.of(script) -> *HTMLElement
 pub fn Struct(comptime T: type) type {
@@ -28,37 +26,3 @@ pub fn Struct(comptime T: type) type {
         else => unreachable,
     };
 }
-
-// Creates an enum of N enums. Doesn't perserve their underlying integer
-pub fn mergeEnums(comptime enums: []const type) type {
-    const field_count = blk: {
-        var count: usize = 0;
-        inline for (enums) |e| {
-            count += @typeInfo(e).@"enum".fields.len;
-        }
-        break :blk count;
-    };
-
-    var i: usize = 0;
-    var fields: [field_count]std.builtin.Type.EnumField = undefined;
-    for (enums) |e| {
-        for (@typeInfo(e).@"enum".fields) |f| {
-            fields[i] = .{
-                .name = f.name,
-                .value = i,
-            };
-            i += 1;
-        }
-    }
-
-    return @Type(.{ .@"enum" = .{
-        .decls = &.{},
-        .tag_type = blk: {
-            if (field_count <= std.math.maxInt(u8)) break :blk u8;
-            if (field_count <= std.math.maxInt(u16)) break :blk u16;
-            unreachable;
-        },
-        .fields = &fields,
-        .is_exhaustive = true,
-    } });
-}

src/browser/tests/console/console.html

@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id="time">
+    // should not crash
+    console.time();
+    console.timeLog();
+    console.timeEnd();
+
+    console.time("test");
+    console.timeLog("test");
+    console.timeEnd("test");
+
+    testing.expectEqual(true, true);
+</script>
+
+<script id="count">
+    // should not crash
+    console.count();
+    console.count();
+    console.countReset();
+
+    console.count("test");
+    console.count("test");
+    console.countReset("test");
+
+    testing.expectEqual(true, true);
+</script>

src/browser/tests/crypto.html

@@ -16,44 +16,44 @@
     isRandom(ti8a)
   }
 
-  // {
-  //   let tu16a = new Uint16Array(100)
-  //   testing.expectEqual(tu16a, crypto.getRandomValues(tu16a))
-  //   isRandom(tu16a)
+  {
+    let tu16a = new Uint16Array(100)
+    testing.expectEqual(tu16a, crypto.getRandomValues(tu16a))
+    isRandom(tu16a)
 
-  //   let ti16a = new Int16Array(100)
-  //   testing.expectEqual(ti16a, crypto.getRandomValues(ti16a))
-  //   isRandom(ti16a)
-  // }
+    let ti16a = new Int16Array(100)
+    testing.expectEqual(ti16a, crypto.getRandomValues(ti16a))
+    isRandom(ti16a)
+  }
 
-  // {
-  //   let tu32a = new Uint32Array(100)
-  //   testing.expectEqual(tu32a, crypto.getRandomValues(tu32a))
-  //   isRandom(tu32a)
+  {
+    let tu32a = new Uint32Array(100)
+    testing.expectEqual(tu32a, crypto.getRandomValues(tu32a))
+    isRandom(tu32a)
 
-  //   let ti32a = new Int32Array(100)
-  //   testing.expectEqual(ti32a, crypto.getRandomValues(ti32a))
-  //   isRandom(ti32a)
-  // }
+    let ti32a = new Int32Array(100)
+    testing.expectEqual(ti32a, crypto.getRandomValues(ti32a))
+    isRandom(ti32a)
+  }
 
-  // {
-  //   let tu64a = new BigUint64Array(100)
-  //   testing.expectEqual(tu64a, crypto.getRandomValues(tu64a))
-  //   isRandom(tu64a)
+  {
+    let tu64a = new BigUint64Array(100)
+    testing.expectEqual(tu64a, crypto.getRandomValues(tu64a))
+    isRandom(tu64a)
 
-  //   let ti64a = new BigInt64Array(100)
-  //   testing.expectEqual(ti64a, crypto.getRandomValues(ti64a))
-  //   isRandom(ti64a)
-  // }
+    let ti64a = new BigInt64Array(100)
+    testing.expectEqual(ti64a, crypto.getRandomValues(ti64a))
+    isRandom(ti64a)
+  }
 </script>
 
-<!-- <script id="randomUUID">
+<script id="randomUUID">
   const uuid = crypto.randomUUID();
   testing.expectEqual('string', typeof uuid);
   testing.expectEqual(36, uuid.length);
   const regex = /^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$/i;
   testing.expectEqual(true, regex.test(uuid));
-</script> -->
+</script>
 
 <script id=SubtleCrypto>
   testing.expectEqual(true, crypto.subtle instanceof SubtleCrypto);
@@ -119,3 +119,16 @@
     testing.expectEqual(16, sharedKey.byteLength);
   });
 </script>
+
+<script id="digest">
+  testing.async(async () => {
+    async function hash(algo, data) {
+      const buffer = await window.crypto.subtle.digest(algo, new TextEncoder().encode(data));
+      return [...new Uint8Array(buffer)].map(x => x.toString(16).padStart(2, '0')).join('');
+    }
+    testing.expectEqual("a6a1e3375239f215f09a156df29c17c7d1ac6722", await hash('sha-1', 'over 9000'));
+    testing.expectEqual("1bc375bb92459685194dda18a4b835f4e2972ec1bde6d9ab3db53fcc584a6580", await hash('sha-256', 'over 9000'));
+    testing.expectEqual("a4260d64c2eea9fd30c1f895c5e48a26d817e19d3a700b61b3ce665864ff4b8e012bd357d345aa614c5f642dab865ea1", await hash('sha-384', 'over 9000'));
+    testing.expectEqual("6cad17e6f3f76680d6dd18ed043b75b4f6e1aa1d08b917294942e882fb6466c3510948c34af8b903ed0725b582b3b39c0e485ae2c1b7dfdb192ee38b79c782b6", await hash('sha-512', 'over 9000'));
+  });
+</script>

src/browser/tests/css.html

@@ -20,8 +20,10 @@
   {
     testing.expectEqual('\\30 abc', CSS.escape('0abc'));
     testing.expectEqual('\\31 23', CSS.escape('123'));
-    testing.expectEqual('\\-test', CSS.escape('-test'));
-    testing.expectEqual('\\--test', CSS.escape('--test'));
+    testing.expectEqual('\\-', CSS.escape('-'));
+    testing.expectEqual('-test', CSS.escape('-test'));
+    testing.expectEqual('--test', CSS.escape('--test'));
+    testing.expectEqual('-\\33 ', CSS.escape('-3'));
   }
 </script>
 

src/browser/tests/custom_elements/registry.html

@@ -119,3 +119,33 @@
 }
 </script>
 
+<script id="constructor_self_insert_foster_parent">
+{
+    // Regression: custom element constructor inserting itself (via appendChild) during
+    // innerHTML parsing. When the element is not valid table content, the HTML5 parser
+    // foster-parents it before the <table> via appendBeforeSiblingCallback. That callback
+    // previously didn't check for an existing _parent before calling insertNodeRelative,
+    // causing the "Page.insertNodeRelative parent" assertion to fire.
+    let constructorCalled = 0;
+    let container;
+
+    class CtorSelfInsert extends HTMLElement {
+        constructor() {
+            super();
+            constructorCalled++;
+            // Insert self into container so _parent is set before the parser
+            // officially places this element via appendBeforeSiblingCallback.
+            if (container) container.appendChild(this);
+        }
+    }
+    customElements.define('ctor-self-insert', CtorSelfInsert);
+
+    container = document.createElement('div');
+    // ctor-self-insert is not valid table content; the parser foster-parents it
+    // before the <table>, calling appendBeforeSiblingCallback(sibling=table, node=element).
+    // At that point the element already has _parent=container from the constructor.
+    container.innerHTML = '<table><ctor-self-insert></ctor-self-insert></table>';
+
+    testing.expectEqual(1, constructorCalled);
+}
+</script>

src/browser/tests/document/create_element.html

@@ -2,12 +2,18 @@
 <body></body>
 <script src="../testing.js"></script>
 <script id=createElement>
-  const div = document.createElement('div');
-  testing.expectEqual("DIV", div.tagName);
-  div.id = "hello";
+  testing.expectEqual(1, document.createElement.length);
+
+  const div1 = document.createElement('div');
+  testing.expectEqual(true, div1 instanceof HTMLDivElement);
+  testing.expectEqual("DIV", div1.tagName);
+  div1.id = "hello";
   testing.expectEqual(null, $('#hello'));
 
-  document.getElementsByTagName('body')[0].appendChild(div);
-  testing.expectEqual(div, $('#hello'));
+  const div2 = document.createElement('DIV');
+  testing.expectEqual(true, div2 instanceof HTMLDivElement);
+
+  document.getElementsByTagName('body')[0].appendChild(div1);
+  testing.expectEqual(div1, $('#hello'));
 </script>
 

src/browser/tests/document/create_element_ns.html

@@ -2,9 +2,15 @@
 <body></body>
 <script src="../testing.js"></script>
 <script id=createElementNS>
-  const htmlDiv = document.createElementNS('http://www.w3.org/1999/xhtml', 'div');
-  testing.expectEqual('DIV', htmlDiv.tagName);
-  testing.expectEqual('http://www.w3.org/1999/xhtml', htmlDiv.namespaceURI);
+  const htmlDiv1 = document.createElementNS('http://www.w3.org/1999/xhtml', 'div');
+  testing.expectEqual('DIV', htmlDiv1.tagName);
+  testing.expectEqual(true, htmlDiv1 instanceof HTMLDivElement);
+  testing.expectEqual('http://www.w3.org/1999/xhtml', htmlDiv1.namespaceURI);
+
+  const htmlDiv2 = document.createElementNS('http://www.w3.org/1999/xhtml', 'DIV');
+  testing.expectEqual('DIV', htmlDiv2.tagName);
+  testing.expectEqual(true, htmlDiv2 instanceof HTMLDivElement);
+  testing.expectEqual('http://www.w3.org/1999/xhtml', htmlDiv2.namespaceURI);
 
   const svgRect = document.createElementNS('http://www.w3.org/2000/svg', 'RecT');
   testing.expectEqual('RecT', svgRect.tagName);

src/browser/tests/document/document.html

@@ -13,6 +13,10 @@
   testing.expectEqual(undefined, document.getCurrentScript);
   testing.expectEqual("http://127.0.0.1:9582/src/browser/tests/document/document.html", document.URL);
   testing.expectEqual(window, document.defaultView);
+  testing.expectEqual(false, document.hidden);
+  testing.expectEqual("visible", document.visibilityState);
+  testing.expectEqual(false, document.prerendering);
+  testing.expectEqual(undefined, Document.prerendering);
 </script>
 
 <script id=headAndbody>
@@ -22,6 +26,7 @@
 
 <script id=documentElement>
   testing.expectEqual($('#the_body').parentNode, document.documentElement);
+  testing.expectEqual(document.documentElement, document.scrollingElement);
 </script>
 
 <script id=title>

src/browser/tests/document/focus.html

@@ -81,6 +81,172 @@
 </script>
 
 
+<script id="focusin_focusout_events">
+{
+  const input1 = $('#input1');
+  const input2 = $('#input2');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  let events = [];
+
+  input1.addEventListener('focus', () => events.push('focus1'));
+  input1.addEventListener('focusin', () => events.push('focusin1'));
+  input1.addEventListener('blur', () => events.push('blur1'));
+  input1.addEventListener('focusout', () => events.push('focusout1'));
+  input2.addEventListener('focus', () => events.push('focus2'));
+  input2.addEventListener('focusin', () => events.push('focusin2'));
+
+  // Focus input1 — should fire focus then focusin
+  input1.focus();
+  testing.expectEqual('focus1,focusin1', events.join(','));
+
+  // Focus input2 — should fire blur, focusout on input1, then focus, focusin on input2
+  events = [];
+  input2.focus();
+  testing.expectEqual('blur1,focusout1,focus2,focusin2', events.join(','));
+}
+</script>
+
+<script id="focusin_bubbles">
+{
+  const input1 = $('#input1');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  let bodyFocusin = 0;
+  let bodyFocus = 0;
+
+  document.body.addEventListener('focusin', () => bodyFocusin++);
+  document.body.addEventListener('focus', () => bodyFocus++);
+
+  input1.focus();
+
+  // focusin should bubble to body, focus should not
+  testing.expectEqual(1, bodyFocusin);
+  testing.expectEqual(0, bodyFocus);
+}
+</script>
+
+<script id="focusout_bubbles">
+{
+  const input1 = $('#input1');
+
+  input1.focus();
+
+  let bodyFocusout = 0;
+  let bodyBlur = 0;
+
+  document.body.addEventListener('focusout', () => bodyFocusout++);
+  document.body.addEventListener('blur', () => bodyBlur++);
+
+  input1.blur();
+
+  // focusout should bubble to body, blur should not
+  testing.expectEqual(1, bodyFocusout);
+  testing.expectEqual(0, bodyBlur);
+}
+</script>
+
+<script id="focus_relatedTarget">
+{
+  const input1 = $('#input1');
+  const input2 = $('#input2');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  let focusRelated = null;
+  let blurRelated = null;
+  let focusinRelated = null;
+  let focusoutRelated = null;
+
+  input1.addEventListener('blur', (e) => { blurRelated = e.relatedTarget; });
+  input1.addEventListener('focusout', (e) => { focusoutRelated = e.relatedTarget; });
+  input2.addEventListener('focus', (e) => { focusRelated = e.relatedTarget; });
+  input2.addEventListener('focusin', (e) => { focusinRelated = e.relatedTarget; });
+
+  input1.focus();
+  input2.focus();
+
+  // blur/focusout on input1 should have relatedTarget = input2 (gaining focus)
+  testing.expectEqual(input2, blurRelated);
+  testing.expectEqual(input2, focusoutRelated);
+
+  // focus/focusin on input2 should have relatedTarget = input1 (losing focus)
+  testing.expectEqual(input1, focusRelated);
+  testing.expectEqual(input1, focusinRelated);
+}
+</script>
+
+<script id="blur_relatedTarget_null">
+{
+  const btn = $('#btn1');
+
+  btn.focus();
+
+  let blurRelated = 'not_set';
+  btn.addEventListener('blur', (e) => { blurRelated = e.relatedTarget; });
+  btn.blur();
+
+  // blur without moving to another element should have relatedTarget = null
+  testing.expectEqual(null, blurRelated);
+}
+</script>
+
+<script id="focus_event_properties">
+{
+  const input1 = $('#input1');
+  const input2 = $('#input2');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  let focusEvent = null;
+  let focusinEvent = null;
+  let blurEvent = null;
+  let focusoutEvent = null;
+
+  input1.addEventListener('blur', (e) => { blurEvent = e; });
+  input1.addEventListener('focusout', (e) => { focusoutEvent = e; });
+  input2.addEventListener('focus', (e) => { focusEvent = e; });
+  input2.addEventListener('focusin', (e) => { focusinEvent = e; });
+
+  input1.focus();
+  input2.focus();
+
+  // All four should be FocusEvent instances
+  testing.expectEqual(true, blurEvent instanceof FocusEvent);
+  testing.expectEqual(true, focusoutEvent instanceof FocusEvent);
+  testing.expectEqual(true, focusEvent instanceof FocusEvent);
+  testing.expectEqual(true, focusinEvent instanceof FocusEvent);
+
+  // All four should be composed per spec
+  testing.expectEqual(true, blurEvent.composed);
+  testing.expectEqual(true, focusoutEvent.composed);
+  testing.expectEqual(true, focusEvent.composed);
+  testing.expectEqual(true, focusinEvent.composed);
+
+  // None should be cancelable
+  testing.expectEqual(false, blurEvent.cancelable);
+  testing.expectEqual(false, focusoutEvent.cancelable);
+  testing.expectEqual(false, focusEvent.cancelable);
+  testing.expectEqual(false, focusinEvent.cancelable);
+
+  // blur/focus don't bubble, focusin/focusout do
+  testing.expectEqual(false, blurEvent.bubbles);
+  testing.expectEqual(true, focusoutEvent.bubbles);
+  testing.expectEqual(false, focusEvent.bubbles);
+  testing.expectEqual(true, focusinEvent.bubbles);
+}
+</script>
+
 <script id="focus_disconnected">
 {
   const focused = document.activeElement;
@@ -88,3 +254,46 @@
   testing.expectEqual(focused, document.activeElement);
 }
 </script>
+
+<script id="click_focuses_element">
+{
+  const input1 = $('#input1');
+  const input2 = $('#input2');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  let focusCount = 0;
+  let blurCount = 0;
+
+  input1.addEventListener('focus', () => focusCount++);
+  input1.addEventListener('blur', () => blurCount++);
+  input2.addEventListener('focus', () => focusCount++);
+
+  // Click input1 — should focus it and fire focus event
+  input1.click();
+  testing.expectEqual(input1, document.activeElement);
+  testing.expectEqual(1, focusCount);
+  testing.expectEqual(0, blurCount);
+
+  // Click input2 — should move focus, fire blur on input1 and focus on input2
+  input2.click();
+  testing.expectEqual(input2, document.activeElement);
+  testing.expectEqual(2, focusCount);
+  testing.expectEqual(1, blurCount);
+}
+</script>
+
+<script id="click_focuses_button">
+{
+  const btn = $('#btn1');
+
+  if (document.activeElement) {
+    document.activeElement.blur();
+  }
+
+  btn.click();
+  testing.expectEqual(btn, document.activeElement);
+}
+</script>

src/browser/tests/document/query_selector.html

@@ -23,6 +23,7 @@
 <main>Main content</main>
 
 <script id=byId name="test1">
+  testing.expectEqual(1, document.querySelector.length);
   testing.expectError("SyntaxError: Syntax Error", () => document.querySelector(''));
   testing.withError((err) => {
     testing.expectEqual(12, err.code);
@@ -269,3 +270,36 @@
   testing.expectEqual('rect', document.querySelector('svg g rect').tagName);
 }
 </script>
+
+<script id=special>
+  testing.expectEqual(null, document.querySelector('\\'));
+
+  testing.expectEqual(null, document.querySelector('div\\'));
+  testing.expectEqual(null, document.querySelector('.test-class\\'));
+  testing.expectEqual(null, document.querySelector('#byId\\'));
+</script>
+
+<div class="café">Non-ASCII class 1</div>
+<div class="日本語">Non-ASCII class 2</div>
+<span id="niño">Non-ASCII ID 1</span>
+<p id="🎨">Non-ASCII ID 2</p>
+
+<script id=nonAsciiSelectors>
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('.café').textContent);
+  testing.expectEqual('Non-ASCII class 2', document.querySelector('.日本語').textContent);
+
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('#niño').textContent);
+  testing.expectEqual('Non-ASCII ID 2', document.querySelector('#🎨').textContent);
+
+  testing.expectEqual('Non-ASCII class 1', document.querySelector('div.café').textContent);
+  testing.expectEqual('Non-ASCII ID 1', document.querySelector('span#niño').textContent);
+</script>
+
+<span id=".,:!">Punctuation test</span>
+
+<script id=escapedPunctuation>
+{
+  // Test escaped punctuation in ID selectors
+  testing.expectEqual('Punctuation test', document.querySelector('#\\.\\,\\:\\!').textContent);
+}
+</script>

src/browser/tests/element/attributes.html

@@ -248,7 +248,7 @@
 }
 </script>
 
-<div id=legacy></a>
+<a id=legacy></a>
 <script id=legacy>
   {
     let a = document.getElementById('legacy').attributes;
@@ -266,3 +266,19 @@
     testing.expectEqual('abc123', a[0].value);
   }
 </script>
+
+<div id="nsa"></div>
+<script id=non-string-attr>
+  {
+    let nsa = document.getElementById('nsa');
+
+    nsa.setAttribute('int', 1);
+    testing.expectEqual('1', nsa.getAttribute('int'));
+
+    nsa.setAttribute('obj', {});
+    testing.expectEqual('[object Object]', nsa.getAttribute('obj'));
+
+    nsa.setAttribute('arr', []);
+    testing.expectEqual('', nsa.getAttribute('arr'));
+  }
+</script>

src/browser/tests/element/class_list.html

@@ -93,6 +93,29 @@
 }
 </script>
 
+<script id=replace_errors>
+{
+  const div = document.createElement('div');
+  div.className = 'foo bar';
+
+  testing.withError((err) => {
+    testing.expectEqual('SyntaxError', err.name);
+  }, () => div.classList.replace('', 'baz'));
+
+  testing.withError((err) => {
+    testing.expectEqual('SyntaxError', err.name);
+  }, () => div.classList.replace('foo', ''));
+
+  testing.withError((err) => {
+    testing.expectEqual('InvalidCharacterError', err.name);
+  }, () => div.classList.replace('foo bar', 'baz'));
+
+  testing.withError((err) => {
+    testing.expectEqual('InvalidCharacterError', err.name);
+  }, () => div.classList.replace('foo', 'bar baz'));
+}
+</script>
+
 <script id=item>
 {
   const div = document.createElement('div');
@@ -166,6 +189,29 @@
 }
 </script>
 
+<script id=classList_assignment>
+{
+  const div = document.createElement('div');
+
+  // Direct assignment should work (equivalent to classList.value = ...)
+  div.classList = 'foo bar baz';
+  testing.expectEqual('foo bar baz', div.className);
+  testing.expectEqual(3, div.classList.length);
+  testing.expectEqual(true, div.classList.contains('foo'));
+
+  // Assigning again should replace
+  div.classList = 'qux';
+  testing.expectEqual('qux', div.className);
+  testing.expectEqual(1, div.classList.length);
+  testing.expectEqual(false, div.classList.contains('foo'));
+
+  // Empty assignment
+  div.classList = '';
+  testing.expectEqual('', div.className);
+  testing.expectEqual(0, div.classList.length);
+}
+</script>
+
 <script id=errors>
 {
   const div = document.createElement('div');

src/browser/tests/element/css_style_properties.html

@@ -121,6 +121,29 @@
 }
 </script>
 
+<script id="propertyAssignment">
+{
+  const div = $('#test-div');
+  div.style.cssText = '';
+
+  // camelCase assignment
+  div.style.opacity = '0.5';
+  testing.expectEqual('0.5', div.style.opacity);
+
+  // bracket notation assignment
+  div.style['filter'] = 'blur(5px)';
+  testing.expectEqual('blur(5px)', div.style.filter);
+
+  // numeric value coerced to string
+  div.style.opacity = 1;
+  testing.expectEqual('1', div.style.opacity);
+
+  // assigning method names should be ignored (not intercepted)
+  div.style.setProperty('color', 'blue');
+  testing.expectEqual('blue', div.style.color);
+}
+</script>
+
 <script id="prototypeChainCheck">
 {
   const div = $('#test-div');

src/browser/tests/element/get_elements_by_tag_name_ns.html

@@ -0,0 +1,123 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<div id="container" xmlns="http://www.w3.org/1999/xhtml">
+  <div id="div1">div1</div>
+  <p id="p1">p1</p>
+  <div id="div2">div2</div>
+</div>
+
+<svg id="svgContainer" xmlns="http://www.w3.org/2000/svg" width="100" height="100">
+  <circle id="circle1" cx="50" cy="50" r="40"/>
+  <rect id="rect1" x="10" y="10" width="30" height="30"/>
+  <circle id="circle2" cx="25" cy="25" r="10"/>
+</svg>
+
+<div id="mixed">
+  <div id="htmlDiv" xmlns="http://www.w3.org/1999/xhtml">HTML div</div>
+  <svg xmlns="http://www.w3.org/2000/svg">
+    <circle id="svgCircle" cx="10" cy="10" r="5"/>
+  </svg>
+</div>
+
+<script id=basic>
+{
+  const htmlNS = "http://www.w3.org/1999/xhtml";
+  const svgNS = "http://www.w3.org/2000/svg";
+
+  // Test HTML namespace
+  const htmlDivs = document.getElementsByTagNameNS(htmlNS, 'div');
+  testing.expectEqual(true, htmlDivs instanceof HTMLCollection);
+  testing.expectEqual(5, htmlDivs.length); // container, div1, div2, mixed, htmlDiv
+
+  const htmlPs = document.getElementsByTagNameNS(htmlNS, 'p');
+  testing.expectEqual(1, htmlPs.length);
+  testing.expectEqual('p1', htmlPs[0].id);
+}
+</script>
+
+<script id=svgNamespace>
+{
+  const svgNS = "http://www.w3.org/2000/svg";
+
+  const circles = document.getElementsByTagNameNS(svgNS, 'circle');
+  testing.expectEqual(3, circles.length); // circle1, circle2, svgCircle
+  testing.expectEqual('circle1', circles[0].id);
+  testing.expectEqual('circle2', circles[1].id);
+  testing.expectEqual('svgCircle', circles[2].id);
+
+  const rects = document.getElementsByTagNameNS(svgNS, 'rect');
+  testing.expectEqual(1, rects.length);
+  testing.expectEqual('rect1', rects[0].id);
+}
+</script>
+
+<script id=nullNamespace>
+{
+  // Null namespace should match elements with null namespace
+  const nullNsElements = document.getElementsByTagNameNS(null, 'div');
+  testing.expectEqual(0, nullNsElements.length); // Our divs are in HTML namespace
+}
+</script>
+
+<script id=wildcardNamespace>
+{
+  // Wildcard namespace "*" should match all namespaces
+  const allDivs = document.getElementsByTagNameNS('*', 'div');
+  testing.expectEqual(5, allDivs.length); // All divs regardless of namespace
+}
+</script>
+
+<script id=wildcardLocalName>
+{
+  const htmlNS = "http://www.w3.org/1999/xhtml";
+
+  // Wildcard local name should match all elements in that namespace
+  const allHtmlElements = document.getElementsByTagNameNS(htmlNS, '*');
+  testing.expectEqual(true, allHtmlElements.length > 0);
+}
+</script>
+
+<script id=caseSensitive>
+{
+  const htmlNS = "http://www.w3.org/1999/xhtml";
+
+  // getElementsByTagNameNS is case-sensitive for local names
+  const lowerDivs = document.getElementsByTagNameNS(htmlNS, 'div');
+  const upperDivs = document.getElementsByTagNameNS(htmlNS, 'DIV');
+
+  testing.expectEqual(5, lowerDivs.length);
+  testing.expectEqual(0, upperDivs.length); // Should be 0 because it's case-sensitive
+}
+</script>
+
+<script id=unknownNamespace>
+{
+  // Unknown namespace should still work
+  const unknownNs = document.getElementsByTagNameNS('http://example.com/unknown', 'div');
+  testing.expectEqual(0, unknownNs.length);
+}
+</script>
+
+<script id=emptyResult>
+{
+  const htmlNS = "http://www.w3.org/1999/xhtml";
+  const svgNS = "http://www.w3.org/2000/svg";
+
+  testing.expectEqual(0, document.getElementsByTagNameNS(htmlNS, 'nonexistent').length);
+  testing.expectEqual(0, document.getElementsByTagNameNS(svgNS, 'nonexistent').length);
+}
+</script>
+
+<script id=elementMethod>
+{
+  const htmlNS = "http://www.w3.org/1999/xhtml";
+  const container = document.getElementById('container');
+
+  // getElementsByTagNameNS on element should only search descendants
+  const divsInContainer = container.getElementsByTagNameNS(htmlNS, 'div');
+  testing.expectEqual(2, divsInContainer.length); // div1, div2 (not container itself)
+  testing.expectEqual('div1', divsInContainer[0].id);
+  testing.expectEqual('div2', divsInContainer[1].id);
+}
+</script>

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

@@ -488,3 +488,27 @@
     testing.expectEqual('function', typeof div.onratechange);
 }
 </script>
+
+<img src="https://cdn.lightpanda.io/website/assets/images/docs/hn.png" />
+
+<script id="document-element-load">
+{
+  let asyncBlockDispatched = false;
+  const docElement = document.documentElement;
+
+  testing.async(async () => {
+    const result = await new Promise(resolve => {
+    // We should get this fired at capturing phase when a resource loaded.
+      docElement.addEventListener("load", e => {
+        testing.expectEqual(e.eventPhase, Event.CAPTURING_PHASE);
+        return resolve(true);
+      }, true);
+    });
+
+    asyncBlockDispatched = true;
+    testing.expectEqual(true, result);
+  });
+
+  testing.eventually(() => testing.expectEqual(true, asyncBlockDispatched));
+}
+</script>

src/browser/tests/element/html/fieldset.html

@@ -0,0 +1,35 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<fieldset id="fs1" disabled name="group1">
+  <input type="text">
+</fieldset>
+<fieldset id="fs2">
+  <input type="text">
+</fieldset>
+
+<script id="disabled">
+  {
+    const fs1 = document.getElementById('fs1');
+    testing.expectEqual(true, fs1.disabled);
+
+    fs1.disabled = false;
+    testing.expectEqual(false, fs1.disabled);
+
+    const fs2 = document.getElementById('fs2');
+    testing.expectEqual(false, fs2.disabled);
+  }
+</script>
+
+<script id="name">
+  {
+    const fs1 = document.getElementById('fs1');
+    testing.expectEqual('group1', fs1.name);
+
+    fs1.name = 'updated';
+    testing.expectEqual('updated', fs1.name);
+
+    const fs2 = document.getElementById('fs2');
+    testing.expectEqual('', fs2.name);
+  }
+</script>

src/browser/tests/element/html/htmlelement-props.html

@@ -0,0 +1,56 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<div id="d1" hidden>Hidden div</div>
+<div id="d2">Visible div</div>
+<input id="i1" tabindex="5">
+<div id="d3">No tabindex</div>
+
+<script id="hidden">
+  {
+    const d1 = document.getElementById('d1');
+    testing.expectEqual(true, d1.hidden);
+
+    d1.hidden = false;
+    testing.expectEqual(false, d1.hidden);
+
+    const d2 = document.getElementById('d2');
+    testing.expectEqual(false, d2.hidden);
+
+    d2.hidden = true;
+    testing.expectEqual(true, d2.hidden);
+  }
+</script>
+
+<script id="tabIndex">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual(5, i1.tabIndex);
+
+    i1.tabIndex = 10;
+    testing.expectEqual(10, i1.tabIndex);
+
+    // Non-interactive elements default to -1
+    const d3 = document.getElementById('d3');
+    testing.expectEqual(-1, d3.tabIndex);
+
+    d3.tabIndex = 0;
+    testing.expectEqual(0, d3.tabIndex);
+
+    // Interactive elements default to 0 per spec
+    const input = document.createElement('input');
+    testing.expectEqual(0, input.tabIndex);
+
+    const button = document.createElement('button');
+    testing.expectEqual(0, button.tabIndex);
+
+    const a = document.createElement('a');
+    testing.expectEqual(0, a.tabIndex);
+
+    const select = document.createElement('select');
+    testing.expectEqual(0, select.tabIndex);
+
+    const textarea = document.createElement('textarea');
+    testing.expectEqual(0, textarea.tabIndex);
+  }
+</script>

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

@@ -97,3 +97,78 @@
     testing.expectEqual('lazy', img.getAttribute('loading'));
 }
 </script>
+
+<script id="complete">
+{
+    // Image with no src is complete per spec
+    const img = document.createElement('img');
+    testing.expectEqual(true, img.complete);
+
+    // Image with src is also complete (headless browser, no actual fetch)
+    img.src = 'test.png';
+    testing.expectEqual(true, img.complete);
+
+    // Image constructor also complete
+    const img2 = new Image();
+    testing.expectEqual(true, img2.complete);
+}
+</script>
+
+<script id="load-trigger-event">
+{
+  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.
+  testing.async(async () => {
+    const result = await new Promise(resolve => {
+      img.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(img, target);
+
+        return resolve(true);
+      });
+    });
+
+    testing.expectEqual(true, result);
+  });
+}
+</script>

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

@@ -0,0 +1,87 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<input id="i1" placeholder="Enter name" min="0" max="100" step="5" autocomplete="email">
+<input id="i2" type="file" multiple>
+<input id="i3">
+
+<script id="placeholder">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual('Enter name', i1.placeholder);
+
+    i1.placeholder = 'Updated';
+    testing.expectEqual('Updated', i1.placeholder);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual('', i3.placeholder);
+  }
+</script>
+
+<script id="min">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual('0', i1.min);
+
+    i1.min = '10';
+    testing.expectEqual('10', i1.min);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual('', i3.min);
+  }
+</script>
+
+<script id="max">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual('100', i1.max);
+
+    i1.max = '200';
+    testing.expectEqual('200', i1.max);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual('', i3.max);
+  }
+</script>
+
+<script id="step">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual('5', i1.step);
+
+    i1.step = '0.5';
+    testing.expectEqual('0.5', i1.step);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual('', i3.step);
+  }
+</script>
+
+<script id="multiple">
+  {
+    const i2 = document.getElementById('i2');
+    testing.expectEqual(true, i2.multiple);
+
+    i2.multiple = false;
+    testing.expectEqual(false, i2.multiple);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual(false, i3.multiple);
+
+    i3.multiple = true;
+    testing.expectEqual(true, i3.multiple);
+  }
+</script>
+
+<script id="autocomplete">
+  {
+    const i1 = document.getElementById('i1');
+    testing.expectEqual('email', i1.autocomplete);
+
+    i1.autocomplete = 'off';
+    testing.expectEqual('off', i1.autocomplete);
+
+    const i3 = document.getElementById('i3');
+    testing.expectEqual('', i3.autocomplete);
+  }
+</script>

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

@@ -183,7 +183,45 @@
 }
 </script>
 
-<!-- <script id="defaultChecked">
+<script id="selectionchange_event">
+  {
+    const input = document.createElement('input');
+    input.value = 'Hello World';
+    document.body.appendChild(input);
+
+    let eventCount = 0;
+    let lastEvent = null;
+    
+    input.addEventListener('selectionchange', (e) => {
+      eventCount++;
+      lastEvent = e;
+    });
+    
+    testing.expectEqual(0, eventCount);
+    
+    input.setSelectionRange(0, 5);
+    input.select();
+    input.selectionStart = 3;
+    input.selectionEnd = 8;
+
+    let bubbledToBody = false;
+    document.body.addEventListener('selectionchange', () => {
+      bubbledToBody = true;
+    });
+    input.setSelectionRange(1, 4);
+
+    testing.eventually(() => {
+      testing.expectEqual(5, eventCount);
+      testing.expectEqual('selectionchange', lastEvent.type);
+      testing.expectEqual(input, lastEvent.target);
+      testing.expectEqual(true, lastEvent.bubbles);
+      testing.expectEqual(false, lastEvent.cancelable);
+      testing.expectEqual(true, bubbledToBody);
+    });
+  }
+</script>
+
+<script id="defaultChecked">
   testing.expectEqual(true, $('#check1').defaultChecked)
   testing.expectEqual(false, $('#check2').defaultChecked)
   testing.expectEqual(true, $('#radio1').defaultChecked)
@@ -455,4 +493,4 @@
     input_checked.defaultChecked = true;
     testing.expectEqual(false, input_checked.checked);
   }
-</script> -->
+</script>

src/browser/tests/element/html/input_click.html

@@ -0,0 +1,283 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<!-- Checkbox click tests -->
+<input id="checkbox1" type="checkbox">
+<input id="checkbox2" type="checkbox" checked>
+<input id="checkbox_disabled" type="checkbox" disabled>
+
+<!-- Radio click tests -->
+<input id="radio1" type="radio" name="clickgroup" checked>
+<input id="radio2" type="radio" name="clickgroup">
+<input id="radio3" type="radio" name="clickgroup">
+<input id="radio_disabled" type="radio" name="clickgroup" disabled>
+
+<script id="checkbox_click_toggles">
+  {
+    const cb = $('#checkbox1');
+    testing.expectEqual(false, cb.checked);
+
+    cb.click();
+    testing.expectEqual(true, cb.checked);
+
+    cb.click();
+    testing.expectEqual(false, cb.checked);
+  }
+</script>
+
+<script id="checkbox_click_preventDefault_reverts">
+  {
+    const cb = document.createElement('input');
+    cb.type = 'checkbox';
+    testing.expectEqual(false, cb.checked);
+
+    cb.addEventListener('click', (e) => {
+      testing.expectEqual(true, cb.checked, 'checkbox should be checked during click handler');
+      e.preventDefault();
+    });
+
+    cb.click();
+    testing.expectEqual(false, cb.checked, 'checkbox should revert after preventDefault');
+  }
+</script>
+
+<script id="checkbox_click_events_order">
+  {
+    const cb = document.createElement('input');
+    cb.type = 'checkbox';
+    document.body.appendChild(cb);
+
+    const events = [];
+
+    cb.addEventListener('click', () => events.push('click'));
+    cb.addEventListener('input', () => events.push('input'));
+    cb.addEventListener('change', () => events.push('change'));
+
+    cb.click();
+
+    testing.expectEqual(3, events.length);
+    testing.expectEqual('click', events[0]);
+    testing.expectEqual('input', events[1]);
+    testing.expectEqual('change', events[2]);
+
+    document.body.removeChild(cb);
+  }
+</script>
+
+<script id="checkbox_click_preventDefault_no_input_change">
+  {
+    const cb = document.createElement('input');
+    cb.type = 'checkbox';
+    document.body.appendChild(cb);
+
+    const events = [];
+
+    cb.addEventListener('click', (e) => {
+      events.push('click');
+      e.preventDefault();
+    });
+    cb.addEventListener('input', () => events.push('input'));
+    cb.addEventListener('change', () => events.push('change'));
+
+    cb.click();
+
+    testing.expectEqual(1, events.length, 'only click event should fire');
+    testing.expectEqual('click', events[0]);
+
+    document.body.removeChild(cb);
+  }
+</script>
+
+<script id="checkbox_click_state_visible_in_handler">
+  {
+    const cb = document.createElement('input');
+    cb.type = 'checkbox';
+    cb.checked = true;
+
+    cb.addEventListener('click', (e) => {
+      testing.expectEqual(false, cb.checked, 'should see toggled state in handler');
+      e.preventDefault();
+      testing.expectEqual(false, cb.checked, 'should still be toggled after preventDefault in handler');
+    });
+
+    cb.click();
+    testing.expectEqual(true, cb.checked, 'should revert to original state after handler completes');
+  }
+</script>
+
+<script id="radio_click_checks_clicked">
+  {
+    const r1 = $('#radio1');
+    const r2 = $('#radio2');
+
+    testing.expectEqual(true, r1.checked);
+    testing.expectEqual(false, r2.checked);
+
+    r2.click();
+    testing.expectEqual(false, r1.checked);
+    testing.expectEqual(true, r2.checked);
+  }
+</script>
+
+<script id="radio_click_preventDefault_reverts">
+  {
+    const r1 = document.createElement('input');
+    r1.type = 'radio';
+    r1.name = 'testgroup';
+    r1.checked = true;
+
+    const r2 = document.createElement('input');
+    r2.type = 'radio';
+    r2.name = 'testgroup';
+
+    document.body.appendChild(r1);
+    document.body.appendChild(r2);
+
+    r2.addEventListener('click', (e) => {
+      testing.expectEqual(false, r1.checked, 'r1 should be unchecked during click handler');
+      testing.expectEqual(true, r2.checked, 'r2 should be checked during click handler');
+      e.preventDefault();
+    });
+
+    r2.click();
+
+    testing.expectEqual(true, r1.checked, 'r1 should be restored after preventDefault');
+    testing.expectEqual(false, r2.checked, 'r2 should revert after preventDefault');
+
+    document.body.removeChild(r1);
+    document.body.removeChild(r2);
+  }
+</script>
+
+<script id="radio_click_events_order">
+  {
+    const r = document.createElement('input');
+    r.type = 'radio';
+    r.name = 'eventtest';
+    document.body.appendChild(r);
+
+    const events = [];
+
+    r.addEventListener('click', () => events.push('click'));
+    r.addEventListener('input', () => events.push('input'));
+    r.addEventListener('change', () => events.push('change'));
+
+    r.click();
+
+    testing.expectEqual(3, events.length);
+    testing.expectEqual('click', events[0]);
+    testing.expectEqual('input', events[1]);
+    testing.expectEqual('change', events[2]);
+
+    document.body.removeChild(r);
+  }
+</script>
+
+<script id="radio_click_already_checked_no_events">
+  {
+    const r = document.createElement('input');
+    r.type = 'radio';
+    r.name = 'alreadytest';
+    r.checked = true;
+    document.body.appendChild(r);
+
+    const events = [];
+
+    r.addEventListener('click', () => events.push('click'));
+    r.addEventListener('input', () => events.push('input'));
+    r.addEventListener('change', () => events.push('change'));
+
+    r.click();
+
+    testing.expectEqual(1, events.length, 'only click event should fire for already-checked radio');
+    testing.expectEqual('click', events[0]);
+
+    document.body.removeChild(r);
+  }
+</script>
+
+<script id="disabled_checkbox_no_click">
+  {
+    const cb = $('#checkbox_disabled');
+    const events = [];
+
+    cb.addEventListener('click', () => events.push('click'));
+    cb.addEventListener('input', () => events.push('input'));
+    cb.addEventListener('change', () => events.push('change'));
+
+    cb.click();
+
+    testing.expectEqual(0, events.length, 'disabled checkbox should not fire any events');
+  }
+</script>
+
+<script id="disabled_radio_no_click">
+  {
+    const r = $('#radio_disabled');
+    const events = [];
+
+    r.addEventListener('click', () => events.push('click'));
+    r.addEventListener('input', () => events.push('input'));
+    r.addEventListener('change', () => events.push('change'));
+
+    r.click();
+
+    testing.expectEqual(0, events.length, 'disabled radio should not fire any events');
+  }
+</script>
+
+<script id="input_and_change_are_trusted">
+  {
+    const cb = document.createElement('input');
+    cb.type = 'checkbox';
+    document.body.appendChild(cb);
+
+    let inputEvent = null;
+    let changeEvent = null;
+
+    cb.addEventListener('input', (e) => inputEvent = e);
+    cb.addEventListener('change', (e) => changeEvent = e);
+
+    cb.click();
+
+    testing.expectEqual(true, inputEvent.isTrusted, 'input event should be trusted');
+    testing.expectEqual(true, inputEvent.bubbles, 'input event should bubble');
+    testing.expectEqual(false, inputEvent.cancelable, 'input event should not be cancelable');
+
+    testing.expectEqual(true, changeEvent.isTrusted, 'change event should be trusted');
+    testing.expectEqual(true, changeEvent.bubbles, 'change event should bubble');
+    testing.expectEqual(false, changeEvent.cancelable, 'change event should not be cancelable');
+
+    document.body.removeChild(cb);
+  }
+</script>
+
+<script id="multiple_radios_click_sequence">
+  {
+    const r1 = $('#radio1');
+    const r2 = $('#radio2');
+    const r3 = $('#radio3');
+
+    // Reset to known state
+    r1.checked = true;
+
+    testing.expectEqual(true, r1.checked);
+    testing.expectEqual(false, r2.checked);
+    testing.expectEqual(false, r3.checked);
+
+    r2.click();
+    testing.expectEqual(false, r1.checked);
+    testing.expectEqual(true, r2.checked);
+    testing.expectEqual(false, r3.checked);
+
+    r3.click();
+    testing.expectEqual(false, r1.checked);
+    testing.expectEqual(false, r2.checked);
+    testing.expectEqual(true, r3.checked);
+
+    r1.click();
+    testing.expectEqual(true, r1.checked);
+    testing.expectEqual(false, r2.checked);
+    testing.expectEqual(false, r3.checked);
+  }
+</script>

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

@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<label id="l1" for="input1">Name</label>
+<input id="input1">
+
+<script id="htmlFor">
+  {
+    const l1 = document.getElementById('l1');
+    testing.expectEqual('input1', l1.htmlFor);
+
+    l1.htmlFor = 'input2';
+    testing.expectEqual('input2', l1.htmlFor);
+
+    const l2 = document.createElement('label');
+    testing.expectEqual('', l2.htmlFor);
+  }
+</script>

src/browser/tests/element/html/li.html

@@ -0,0 +1,23 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<ol>
+  <li id="li1" value="5">Item</li>
+  <li id="li2">Item</li>
+</ol>
+
+<script id="value">
+  {
+    const li1 = document.getElementById('li1');
+    testing.expectEqual(5, li1.value);
+
+    li1.value = 10;
+    testing.expectEqual(10, li1.value);
+
+    const li2 = document.getElementById('li2');
+    testing.expectEqual(0, li2.value);
+
+    li2.value = -3;
+    testing.expectEqual(-3, li2.value);
+  }
+</script>

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

@@ -9,4 +9,13 @@
 
   l2.href = '/over/9000';
   testing.expectEqual('http://127.0.0.1:9582/over/9000', l2.href);
+
+  l2.crossOrigin = 'nope';
+  testing.expectEqual('anonymous', l2.crossOrigin);
+
+  l2.crossOrigin = 'use-Credentials';
+  testing.expectEqual('use-credentials', l2.crossOrigin);
+
+  l2.crossOrigin = '';
+  testing.expectEqual('anonymous', l2.crossOrigin);
 </script>

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

@@ -50,6 +50,50 @@
   }
 </script>
 
+<script id="play_pause_events">
+  {
+    const audio = document.createElement('audio');
+    const events = [];
+
+    audio.addEventListener('play', () => events.push('play'));
+    audio.addEventListener('playing', () => events.push('playing'));
+    audio.addEventListener('pause', () => events.push('pause'));
+    audio.addEventListener('emptied', () => events.push('emptied'));
+
+    // First play: paused -> playing, fires play + playing
+    audio.play();
+    testing.expectEqual('play,playing', events.join(','));
+
+    // Second play: already playing, no events
+    audio.play();
+    testing.expectEqual('play,playing', events.join(','));
+
+    // Pause: playing -> paused, fires pause
+    audio.pause();
+    testing.expectEqual('play,playing,pause', events.join(','));
+
+    // Second pause: already paused, no event
+    audio.pause();
+    testing.expectEqual('play,playing,pause', events.join(','));
+
+    // Third play: resume from pause, fires play + playing (verified in Chrome)
+    audio.play();
+    testing.expectEqual('play,playing,pause,play,playing', events.join(','));
+
+    // Pause again
+    audio.pause();
+    testing.expectEqual('play,playing,pause,play,playing,pause', events.join(','));
+
+    // Load: resets state, fires emptied
+    audio.load();
+    testing.expectEqual('play,playing,pause,play,playing,pause,emptied', events.join(','));
+
+    // Play after load: fires play + playing
+    audio.play();
+    testing.expectEqual('play,playing,pause,play,playing,pause,emptied,play,playing', events.join(','));
+  }
+</script>
+
 <script id="volume_muted">
   {
     const audio = document.getElementById('audio1');

src/browser/tests/element/html/ol.html

@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<ol id="ol1" start="5" reversed type="a">
+  <li>Item</li>
+</ol>
+<ol id="ol2">
+  <li>Item</li>
+</ol>
+
+<script id="start">
+  {
+    const ol1 = document.getElementById('ol1');
+    testing.expectEqual(5, ol1.start);
+
+    ol1.start = 10;
+    testing.expectEqual(10, ol1.start);
+
+    const ol2 = document.getElementById('ol2');
+    testing.expectEqual(1, ol2.start);
+  }
+</script>
+
+<script id="reversed">
+  {
+    const ol1 = document.getElementById('ol1');
+    testing.expectEqual(true, ol1.reversed);
+
+    ol1.reversed = false;
+    testing.expectEqual(false, ol1.reversed);
+
+    const ol2 = document.getElementById('ol2');
+    testing.expectEqual(false, ol2.reversed);
+
+    ol2.reversed = true;
+    testing.expectEqual(true, ol2.reversed);
+  }
+</script>
+
+<script id="type">
+  {
+    const ol1 = document.getElementById('ol1');
+    testing.expectEqual('a', ol1.type);
+
+    ol1.type = '1';
+    testing.expectEqual('1', ol1.type);
+
+    const ol2 = document.getElementById('ol2');
+    testing.expectEqual('1', ol2.type);
+  }
+</script>

src/browser/tests/element/html/optgroup.html

@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<select>
+  <optgroup id="og1" label="Group 1" disabled>
+    <option>A</option>
+  </optgroup>
+  <optgroup id="og2" label="Group 2">
+    <option>B</option>
+  </optgroup>
+</select>
+
+<script id="disabled">
+  {
+    const og1 = document.getElementById('og1');
+    testing.expectEqual(true, og1.disabled);
+
+    og1.disabled = false;
+    testing.expectEqual(false, og1.disabled);
+
+    const og2 = document.getElementById('og2');
+    testing.expectEqual(false, og2.disabled);
+
+    og2.disabled = true;
+    testing.expectEqual(true, og2.disabled);
+  }
+</script>
+
+<script id="label">
+  {
+    const og1 = document.getElementById('og1');
+    testing.expectEqual('Group 1', og1.label);
+
+    og1.label = 'Updated';
+    testing.expectEqual('Updated', og1.label);
+
+    const og = document.createElement('optgroup');
+    testing.expectEqual('', og.label);
+  }
+</script>

src/browser/tests/element/html/picture.html

@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<!-- <script id="createElement">
+{
+    const picture = document.createElement('picture');
+    testing.expectEqual('PICTURE', picture.tagName);
+    testing.expectEqual('[object HTMLPictureElement]', Object.prototype.toString.call(picture));
+}
+</script>
+
+<script id="constructor_type">
+{
+    const picture = document.createElement('picture');
+    testing.expectEqual(true, picture instanceof HTMLElement);
+    testing.expectEqual(true, picture instanceof Element);
+    testing.expectEqual(true, picture instanceof Node);
+}
+</script> -->
+
+<picture id="inline-picture">
+  <source media="(min-width: 800px)" srcset="large.jpg">
+  <source media="(min-width: 400px)" srcset="medium.jpg">
+  <img src="small.jpg" alt="Test image">
+</picture>
+
+<script id="inline_picture">
+{
+    const picture = document.getElementById('inline-picture');
+    testing.expectEqual('PICTURE', picture.tagName);
+    testing.expectEqual(3, picture.children.length);
+
+    const sources = picture.querySelectorAll('source');
+    testing.expectEqual(2, sources.length);
+
+    // const img = picture.querySelector('img');
+    // testing.expectEqual('IMG', img.tagName);
+}
+</script>
+
+<!-- <script id="appendChild">
+{
+    const picture = document.createElement('picture');
+    const source = document.createElement('source');
+    const img = document.createElement('img');
+
+    picture.appendChild(source);
+    picture.appendChild(img);
+
+    testing.expectEqual(2, picture.children.length);
+    testing.expectEqual('SOURCE', picture.children[0].tagName);
+    testing.expectEqual('IMG', picture.children[1].tagName);
+}
+</script>
+ -->

src/browser/tests/element/html/quote.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<blockquote id="q1" cite="https://example.com/source">Quote</blockquote>
+
+<script id="cite">
+  {
+    const q1 = document.getElementById('q1');
+    testing.expectEqual('https://example.com/source', q1.cite);
+
+    q1.cite = 'https://example.com/other';
+    testing.expectEqual('https://example.com/other', q1.cite);
+
+    const q2 = document.createElement('blockquote');
+    testing.expectEqual('', q2.cite);
+  }
+</script>

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

@@ -3,7 +3,46 @@
 
 <script id="sheet">
   {
+    // Disconnected style element should have no sheet
     testing.expectEqual(null, document.createElement('style').sheet);
+
+    // Connected style element should have a CSSStyleSheet
+    const style = document.createElement('style');
+    document.head.appendChild(style);
+    testing.expectEqual(true, style.sheet instanceof CSSStyleSheet);
+
+    // Same sheet instance on repeated access
+    testing.expectEqual(true, style.sheet === style.sheet);
+
+    // Non-CSS type should have no sheet
+    const lessStyle = document.createElement('style');
+    lessStyle.type = 'text/less';
+    document.head.appendChild(lessStyle);
+    testing.expectEqual(null, lessStyle.sheet);
+
+    // Empty type attribute is valid (defaults to text/css per spec)
+    const emptyType = document.createElement('style');
+    emptyType.setAttribute('type', '');
+    document.head.appendChild(emptyType);
+    testing.expectEqual(true, emptyType.sheet instanceof CSSStyleSheet);
+
+    // Case-insensitive type check
+    const upperType = document.createElement('style');
+    upperType.type = 'TEXT/CSS';
+    document.head.appendChild(upperType);
+    testing.expectEqual(true, upperType.sheet instanceof CSSStyleSheet);
+
+    // Disconnection clears sheet
+    const tempStyle = document.createElement('style');
+    document.head.appendChild(tempStyle);
+    testing.expectEqual(true, tempStyle.sheet instanceof CSSStyleSheet);
+    document.head.removeChild(tempStyle);
+    testing.expectEqual(null, tempStyle.sheet);
+
+    // ownerNode points back to the style element
+    const ownStyle = document.createElement('style');
+    document.head.appendChild(ownStyle);
+    testing.expectEqual(true, ownStyle.sheet.ownerNode === ownStyle);
   }
 </script>
 

src/browser/tests/element/html/tablecell.html

@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<table>
+  <tr>
+    <td id="td1" colspan="3" rowspan="2">Cell</td>
+    <td id="td2">Cell</td>
+  </tr>
+</table>
+
+<script id="colSpan">
+  {
+    const td1 = document.getElementById('td1');
+    testing.expectEqual(3, td1.colSpan);
+
+    td1.colSpan = 5;
+    testing.expectEqual(5, td1.colSpan);
+
+    const td2 = document.getElementById('td2');
+    testing.expectEqual(1, td2.colSpan);
+
+    // colSpan 0 clamps to 1
+    td2.colSpan = 0;
+    testing.expectEqual(1, td2.colSpan);
+
+    // colSpan > 1000 clamps to 1000
+    td2.colSpan = 9999;
+    testing.expectEqual(1000, td2.colSpan);
+  }
+</script>
+
+<script id="rowSpan">
+  {
+    const td1 = document.getElementById('td1');
+    testing.expectEqual(2, td1.rowSpan);
+
+    td1.rowSpan = 4;
+    testing.expectEqual(4, td1.rowSpan);
+
+    const td2 = document.getElementById('td2');
+    testing.expectEqual(1, td2.rowSpan);
+
+    // rowSpan 0 is valid per spec (span remaining rows)
+    td2.rowSpan = 0;
+    testing.expectEqual(0, td2.rowSpan);
+
+    // rowSpan > 65534 clamps to 65534
+    td2.rowSpan = 99999;
+    testing.expectEqual(65534, td2.rowSpan);
+  }
+</script>

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

@@ -229,3 +229,41 @@
     testing.expectEqual('some content', clone.value)
   }
 </script>
+
+<script id="selectionchange_event">
+  {
+    const textarea = document.createElement('textarea');
+    textarea.value = 'Hello World';
+    document.body.appendChild(textarea);
+    
+    let eventCount = 0;
+    let lastEvent = null;
+    
+    textarea.addEventListener('selectionchange', (e) => {
+      eventCount++;
+      lastEvent = e;
+    });
+    
+    testing.expectEqual(0, eventCount);
+    
+    textarea.setSelectionRange(0, 5);
+    textarea.select();
+    textarea.selectionStart = 3;
+    textarea.selectionEnd = 8;
+    
+    let bubbledToBody = false;
+    document.body.addEventListener('selectionchange', () => {
+      bubbledToBody = true;
+    });
+    textarea.setSelectionRange(1, 4);
+    
+    testing.eventually(() => {
+      testing.expectEqual(5, eventCount);
+      testing.expectEqual('selectionchange', lastEvent.type);
+      testing.expectEqual(textarea, lastEvent.target);
+      testing.expectEqual(true, lastEvent.bubbles);
+      testing.expectEqual(false, lastEvent.cancelable);
+      testing.expectEqual(true, bubbledToBody);
+    });
+  }
+</script>

src/browser/tests/element/html/time.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="../../testing.js"></script>
+
+<time id="t1" datetime="2024-01-15">January 15</time>
+
+<script id="dateTime">
+  {
+    const t = document.getElementById('t1');
+    testing.expectEqual('2024-01-15', t.dateTime);
+
+    t.dateTime = '2024-12-25T10:00';
+    testing.expectEqual('2024-12-25T10:00', t.dateTime);
+
+    const t2 = document.createElement('time');
+    testing.expectEqual('', t2.dateTime);
+  }
+</script>

src/browser/tests/element/position.html

@@ -0,0 +1,116 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<div id="test1">Test Element</div>
+<div id="test2">Another Element</div>
+
+<script id="clientDimensions">
+{
+  const test1 = $('#test1');
+
+  // clientWidth/Height - default is 5px in dummy layout
+  testing.expectEqual('number', typeof test1.clientWidth);
+  testing.expectEqual('number', typeof test1.clientHeight);
+  testing.expectTrue(test1.clientWidth >= 0);
+  testing.expectTrue(test1.clientHeight >= 0);
+
+  // clientTop/Left should be 0 (no borders in dummy layout)
+  testing.expectEqual(0, test1.clientTop);
+  testing.expectEqual(0, test1.clientLeft);
+}
+</script>
+
+<script id="scrollDimensions">
+{
+  const test1 = $('#test1');
+
+  // In dummy layout, scroll dimensions equal client dimensions (no overflow)
+  testing.expectEqual(test1.clientWidth, test1.scrollWidth);
+  testing.expectEqual(test1.clientHeight, test1.scrollHeight);
+}
+</script>
+
+<script id="scrollPosition">
+{
+  const test1 = $('#test1');
+
+  // Initial scroll position should be 0
+  testing.expectEqual(0, test1.scrollTop);
+  testing.expectEqual(0, test1.scrollLeft);
+
+  // Setting scroll position
+  test1.scrollTop = 50;
+  testing.expectEqual(50, test1.scrollTop);
+
+  test1.scrollLeft = 25;
+  testing.expectEqual(25, test1.scrollLeft);
+
+  // Negative values should be clamped to 0
+  test1.scrollTop = -10;
+  testing.expectEqual(0, test1.scrollTop);
+
+  test1.scrollLeft = -5;
+  testing.expectEqual(0, test1.scrollLeft);
+
+  // Each element has independent scroll position
+  const test2 = $('#test2');
+  testing.expectEqual(0, test2.scrollTop);
+  testing.expectEqual(0, test2.scrollLeft);
+
+  test2.scrollTop = 100;
+  testing.expectEqual(100, test2.scrollTop);
+  testing.expectEqual(0, test1.scrollTop); // test1 should still be 0
+}
+</script>
+
+<script id="offsetDimensions">
+{
+  const test1 = $('#test1');
+
+  // offsetWidth/Height should be numbers
+  testing.expectEqual('number', typeof test1.offsetWidth);
+  testing.expectEqual('number', typeof test1.offsetHeight);
+  testing.expectTrue(test1.offsetWidth >= 0);
+  testing.expectTrue(test1.offsetHeight >= 0);
+
+  // Should equal client dimensions
+  testing.expectEqual(test1.clientWidth, test1.offsetWidth);
+  testing.expectEqual(test1.clientHeight, test1.offsetHeight);
+}
+</script>
+
+<script id="offsetPosition">
+{
+  const test1 = $('#test1');
+  const test2 = $('#test2');
+
+  // offsetTop/Left should be calculated from tree position
+  // These values are based on the heuristic layout engine
+  const top1 = test1.offsetTop;
+  const left1 = test1.offsetLeft;
+  const top2 = test2.offsetTop;
+  const left2 = test2.offsetLeft;
+
+  // Position values should be numbers
+  testing.expectEqual('number', typeof top1);
+  testing.expectEqual('number', typeof left1);
+  testing.expectEqual('number', typeof top2);
+  testing.expectEqual('number', typeof left2);
+
+  // Siblings should have different positions (either different x or y)
+  testing.expectTrue(top1 !== top2 || left1 !== left2);
+}
+</script>
+
+<script id="offsetVsBounding">
+{
+  const test1 = $('#test1');
+
+  // offsetTop/Left should match getBoundingClientRect
+  const rect = test1.getBoundingClientRect();
+  testing.expectEqual(rect.y, test1.offsetTop);
+  testing.expectEqual(rect.x, test1.offsetLeft);
+  testing.expectEqual(rect.width, test1.offsetWidth);
+  testing.expectEqual(rect.height, test1.offsetHeight);
+}
+</script>

src/browser/tests/element/replace_with.html

@@ -0,0 +1,334 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<!-- Test 1: Basic single element replacement -->
+<div id="test1">
+  <div id="parent1">
+    <div id="old1">Old Content</div>
+  </div>
+</div>
+
+<script id="test1-basic-replacement">
+  const old1 = $('#old1');
+  const parent1 = $('#parent1');
+
+  testing.expectEqual(1, parent1.childElementCount);
+  testing.expectEqual(old1, document.getElementById('old1'));
+
+  const new1 = document.createElement('div');
+  new1.id = 'new1';
+  new1.textContent = 'New Content';
+
+  old1.replaceWith(new1);
+
+  testing.expectEqual(1, parent1.childElementCount);
+  testing.expectEqual(null, document.getElementById('old1'));
+  testing.expectEqual(new1, document.getElementById('new1'));
+  testing.expectEqual(parent1, new1.parentElement);
+</script>
+
+<!-- Test 2: Replace with multiple elements -->
+<div id="test2">
+  <div id="parent2">
+    <div id="old2">Old</div>
+  </div>
+</div>
+
+<script id="test2-multiple-elements">
+  const old2 = $('#old2');
+  const parent2 = $('#parent2');
+
+  testing.expectEqual(1, parent2.childElementCount);
+
+  const new2a = document.createElement('div');
+  new2a.id = 'new2a';
+  const new2b = document.createElement('div');
+  new2b.id = 'new2b';
+  const new2c = document.createElement('div');
+  new2c.id = 'new2c';
+
+  old2.replaceWith(new2a, new2b, new2c);
+
+  testing.expectEqual(3, parent2.childElementCount);
+  testing.expectEqual(null, document.getElementById('old2'));
+  testing.expectEqual(new2a, document.getElementById('new2a'));
+  testing.expectEqual(new2b, document.getElementById('new2b'));
+  testing.expectEqual(new2c, document.getElementById('new2c'));
+
+  // Check order
+  testing.expectEqual(new2a, parent2.children[0]);
+  testing.expectEqual(new2b, parent2.children[1]);
+  testing.expectEqual(new2c, parent2.children[2]);
+</script>
+
+<!-- Test 3: Replace with text nodes -->
+<div id="test3">
+  <div id="parent3"><div id="old3">Old</div></div>
+</div>
+
+<script id="test3-text-nodes">
+  const old3 = $('#old3');
+  const parent3 = $('#parent3');
+
+  old3.replaceWith('Text1', ' ', 'Text2');
+
+  testing.expectEqual(null, document.getElementById('old3'));
+  testing.expectEqual('Text1 Text2', parent3.textContent);
+</script>
+
+<!-- Test 4: Replace with mix of elements and text -->
+<div id="test4">
+  <div id="parent4"><div id="old4">Old</div></div>
+</div>
+
+<script id="test4-mixed">
+  const old4 = $('#old4');
+  const parent4 = $('#parent4');
+
+  const new4 = document.createElement('span');
+  new4.id = 'new4';
+  new4.textContent = 'Element';
+
+  old4.replaceWith('Before ', new4, ' After');
+
+  testing.expectEqual(null, document.getElementById('old4'));
+  testing.expectEqual(new4, document.getElementById('new4'));
+  testing.expectEqual('Before Element After', parent4.textContent);
+</script>
+
+<!-- Test 5: Replace element not connected to document -->
+<script id="test5-not-connected">
+  const disconnected = document.createElement('div');
+  disconnected.id = 'disconnected5';
+
+  const replacement = document.createElement('div');
+  replacement.id = 'replacement5';
+
+  // Should do nothing since element has no parent
+  disconnected.replaceWith(replacement);
+
+  // Neither should be in the document
+  testing.expectEqual(null, document.getElementById('disconnected5'));
+  testing.expectEqual(null, document.getElementById('replacement5'));
+</script>
+
+<!-- Test 6: Replace with nodes that already have a parent -->
+<div id="test6">
+  <div id="parent6a">
+    <div id="old6">Old</div>
+  </div>
+  <div id="parent6b">
+    <div id="moving6a">Moving A</div>
+    <div id="moving6b">Moving B</div>
+  </div>
+</div>
+
+<script id="test6-moving-nodes">
+  const old6 = $('#old6');
+  const parent6a = $('#parent6a');
+  const parent6b = $('#parent6b');
+  const moving6a = $('#moving6a');
+  const moving6b = $('#moving6b');
+
+  testing.expectEqual(1, parent6a.childElementCount);
+  testing.expectEqual(2, parent6b.childElementCount);
+
+  // Replace old6 with nodes that already have parent6b as parent
+  old6.replaceWith(moving6a, moving6b);
+
+  // old6 should be gone
+  testing.expectEqual(null, document.getElementById('old6'));
+
+  // parent6a should now have the moved elements
+  testing.expectEqual(2, parent6a.childElementCount);
+  testing.expectEqual(moving6a, parent6a.children[0]);
+  testing.expectEqual(moving6b, parent6a.children[1]);
+
+  // parent6b should now be empty
+  testing.expectEqual(0, parent6b.childElementCount);
+
+  // getElementById should still work
+  testing.expectEqual(moving6a, document.getElementById('moving6a'));
+  testing.expectEqual(moving6b, document.getElementById('moving6b'));
+  testing.expectEqual(parent6a, moving6a.parentElement);
+  testing.expectEqual(parent6a, moving6b.parentElement);
+</script>
+
+<!-- Test 7: Replace with nested elements -->
+<div id="test7">
+  <div id="parent7">
+    <div id="old7">Old</div>
+  </div>
+</div>
+
+<script id="test7-nested">
+  const old7 = $('#old7');
+  const parent7 = $('#parent7');
+
+  const new7 = document.createElement('div');
+  new7.id = 'new7';
+
+  const child7a = document.createElement('div');
+  child7a.id = 'child7a';
+  const child7b = document.createElement('div');
+  child7b.id = 'child7b';
+
+  new7.appendChild(child7a);
+  new7.appendChild(child7b);
+
+  old7.replaceWith(new7);
+
+  testing.expectEqual(null, document.getElementById('old7'));
+  testing.expectEqual(new7, document.getElementById('new7'));
+  testing.expectEqual(child7a, document.getElementById('child7a'));
+  testing.expectEqual(child7b, document.getElementById('child7b'));
+  testing.expectEqual(2, new7.childElementCount);
+</script>
+
+<!-- Test 8: Replace maintains sibling order -->
+<div id="test8">
+  <div id="parent8">
+    <div id="before8">Before</div>
+    <div id="old8">Old</div>
+    <div id="after8">After</div>
+  </div>
+</div>
+
+<script id="test8-sibling-order">
+  const old8 = $('#old8');
+  const parent8 = $('#parent8');
+  const before8 = $('#before8');
+  const after8 = $('#after8');
+
+  testing.expectEqual(3, parent8.childElementCount);
+
+  const new8 = document.createElement('div');
+  new8.id = 'new8';
+
+  old8.replaceWith(new8);
+
+  testing.expectEqual(3, parent8.childElementCount);
+  testing.expectEqual(before8, parent8.children[0]);
+  testing.expectEqual(new8, parent8.children[1]);
+  testing.expectEqual(after8, parent8.children[2]);
+</script>
+
+<!-- Test 9: Replace first child -->
+<div id="test9">
+  <div id="parent9">
+    <div id="first9">First</div>
+    <div id="second9">Second</div>
+  </div>
+</div>
+
+<script id="test9-first-child">
+  const first9 = $('#first9');
+  const parent9 = $('#parent9');
+
+  const new9 = document.createElement('div');
+  new9.id = 'new9';
+
+  first9.replaceWith(new9);
+
+  testing.expectEqual(null, document.getElementById('first9'));
+  testing.expectEqual(new9, parent9.firstElementChild);
+  testing.expectEqual(new9, parent9.children[0]);
+</script>
+
+<!-- Test 10: Replace last child -->
+<div id="test10">
+  <div id="parent10">
+    <div id="first10">First</div>
+    <div id="last10">Last</div>
+  </div>
+</div>
+
+<script id="test10-last-child">
+  const last10 = $('#last10');
+  const parent10 = $('#parent10');
+
+  const new10 = document.createElement('div');
+  new10.id = 'new10';
+
+  last10.replaceWith(new10);
+
+  testing.expectEqual(null, document.getElementById('last10'));
+  testing.expectEqual(new10, parent10.lastElementChild);
+  testing.expectEqual(new10, parent10.children[1]);
+</script>
+
+<!-- Test 11: Replace with empty (no arguments) - effectively removes the element -->
+<div id="test11">
+  <div id="parent11">
+    <div id="old11">Old</div>
+  </div>
+</div>
+
+<script id="test11-empty">
+  const old11 = $('#old11');
+  const parent11 = $('#parent11');
+
+  testing.expectEqual(1, parent11.childElementCount);
+
+  // Calling replaceWith() with no args should just remove the element
+  old11.replaceWith();
+
+  // Element should be removed, leaving parent empty
+  testing.expectEqual(0, parent11.childElementCount);
+  testing.expectEqual(null, document.getElementById('old11'));
+  testing.expectEqual(null, old11.parentElement);
+</script>
+
+<!-- Test 12: Replace and check childElementCount updates -->
+<div id="test12">
+  <div id="parent12">
+    <div id="a12">A</div>
+    <div id="b12">B</div>
+    <div id="c12">C</div>
+  </div>
+</div>
+
+<script id="test12-child-count">
+  const b12 = $('#b12');
+  const parent12 = $('#parent12');
+
+  testing.expectEqual(3, parent12.childElementCount);
+
+  // Replace with 2 elements
+  const new12a = document.createElement('div');
+  new12a.id = 'new12a';
+  const new12b = document.createElement('div');
+  new12b.id = 'new12b';
+
+  b12.replaceWith(new12a, new12b);
+
+  testing.expectEqual(4, parent12.childElementCount);
+  testing.expectEqual(null, document.getElementById('b12'));
+</script>
+
+<!-- Test 13: Replace deeply nested element -->
+<div id="test13">
+  <div id="l1">
+    <div id="l2">
+      <div id="l3">
+        <div id="l4">
+          <div id="old13">Deep</div>
+        </div>
+      </div>
+    </div>
+  </div>
+</div>
+
+<script id="test13-deeply-nested">
+  const old13 = $('#old13');
+  const l4 = $('#l4');
+
+  const new13 = document.createElement('div');
+  new13.id = 'new13';
+
+  old13.replaceWith(new13);
+
+  testing.expectEqual(null, document.getElementById('old13'));
+  testing.expectEqual(new13, document.getElementById('new13'));
+  testing.expectEqual(l4, new13.parentElement);
+</script>

src/browser/tests/event/focus.html

@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+<script id=default>
+  let event = new FocusEvent('focus');
+  testing.expectEqual('focus', event.type);
+  testing.expectEqual(true, event instanceof FocusEvent);
+  testing.expectEqual(true, event instanceof UIEvent);
+  testing.expectEqual(true, event instanceof Event);
+  testing.expectEqual(null, event.relatedTarget);
+</script>
+
+<script id=parameters>
+  let div = document.createElement('div');
+  let focusEvent = new FocusEvent('blur', { relatedTarget: div });
+  testing.expectEqual(div, focusEvent.relatedTarget);
+</script>
+
+<script id=createEvent>
+  let evt = document.createEvent('focusevent');
+  testing.expectEqual(true, evt instanceof FocusEvent);
+  testing.expectEqual(true, evt instanceof UIEvent);
+</script>

src/browser/tests/event/mouse.html

@@ -10,11 +10,13 @@
   testing.expectEqual(0, event.clientY);
   testing.expectEqual(0, event.screenX);
   testing.expectEqual(0, event.screenY);
+  testing.expectEqual(0, event.buttons);
 </script>
 
 <script id=parameters>
-  let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20, screenX: 200, screenY: 500 });
+  let new_event = new MouseEvent('click', { 'button': 0, 'clientX': 10, 'clientY': 20, screenX: 200, screenY: 500, buttons: 5 });
   testing.expectEqual(0, new_event.button);
+  testing.expectEqual(5, new_event.buttons);
   testing.expectEqual(10, new_event.x);
   testing.expectEqual(20, new_event.y);
   testing.expectEqual(10, new_event.pageX);

src/browser/tests/event/promise_rejection.html

@@ -0,0 +1,22 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id=project_rejection>
+  {
+    let e1 = new PromiseRejectionEvent("rejectionhandled");
+    testing.expectEqual(true, e1 instanceof PromiseRejectionEvent);
+    testing.expectEqual(true, e1 instanceof Event);
+
+    testing.expectEqual("rejectionhandled", e1.type);
+    testing.expectEqual(null, e1.reason);
+    testing.expectEqual(null, e1.promise);
+
+    let e2 = new PromiseRejectionEvent("rejectionhandled", {reason: ['tea']});
+    testing.expectEqual(true, e2 instanceof PromiseRejectionEvent);
+    testing.expectEqual(true, e2 instanceof Event);
+
+    testing.expectEqual("rejectionhandled", e2.type);
+    testing.expectEqual(['tea'], e2.reason);
+    testing.expectEqual(null, e2.promise);
+  }
+</script>

src/browser/tests/event/text.html

@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+<script id=createEvent>
+  let evt = document.createEvent('TextEvent');
+  testing.expectEqual(true, evt instanceof TextEvent);
+  testing.expectEqual(true, evt instanceof UIEvent);
+  testing.expectEqual('', evt.data);
+</script>
+
+<script id=initTextEvent>
+  let textEvent = document.createEvent('TextEvent');
+  textEvent.initTextEvent('textInput', true, false, window, 'test data');
+  testing.expectEqual('textInput', textEvent.type);
+  testing.expectEqual('test data', textEvent.data);
+  testing.expectEqual(true, textEvent.bubbles);
+  testing.expectEqual(false, textEvent.cancelable);
+</script>

src/browser/tests/event/wheel.html

@@ -0,0 +1,30 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+<script id=default>
+  let event = new WheelEvent('wheel');
+  testing.expectEqual('wheel', event.type);
+  testing.expectEqual(true, event instanceof WheelEvent);
+  testing.expectEqual(true, event instanceof MouseEvent);
+  testing.expectEqual(true, event instanceof UIEvent);
+  testing.expectEqual(0, event.deltaX);
+  testing.expectEqual(0, event.deltaY);
+  testing.expectEqual(0, event.deltaZ);
+  testing.expectEqual(0, event.deltaMode);
+</script>
+
+<script id=parameters>
+  let wheelEvent = new WheelEvent('wheel', {
+    deltaX: 10,
+    deltaY: 20,
+    deltaMode: WheelEvent.DOM_DELTA_LINE
+  });
+  testing.expectEqual(10, wheelEvent.deltaX);
+  testing.expectEqual(20, wheelEvent.deltaY);
+  testing.expectEqual(1, wheelEvent.deltaMode);
+</script>
+
+<script id=constants>
+  testing.expectEqual(0, WheelEvent.DOM_DELTA_PIXEL);
+  testing.expectEqual(1, WheelEvent.DOM_DELTA_LINE);
+  testing.expectEqual(2, WheelEvent.DOM_DELTA_PAGE);
+</script>

src/browser/tests/events.html

@@ -635,3 +635,130 @@
   // https://github.com/lightpanda-io/browser/pull/1316
   testing.expectError('TypeError', () => MessageEvent(''));
 </script>
+
+<div id=inline_parent><div id=inline_child></div></div>
+<script id=inlineHandlerReceivesEvent>
+  // Test that inline onclick handler receives the event object
+  {
+    const inline_child = $('#inline_child');
+    let receivedType = null;
+    let receivedTarget = null;
+    let receivedCurrentTarget = null;
+
+    inline_child.onclick = function(e) {
+      // Capture values DURING handler execution
+      receivedType = e.type;
+      receivedTarget = e.target;
+      receivedCurrentTarget = e.currentTarget;
+    };
+
+    inline_child.click();
+
+    testing.expectEqual('click', receivedType);
+    testing.expectEqual(inline_child, receivedTarget);
+    testing.expectEqual(inline_child, receivedCurrentTarget);
+  }
+</script>
+
+<div id=inline_order_parent><div id=inline_order_child></div></div>
+<script id=inlineHandlerOrder>
+  // Test that inline handler executes in proper order with addEventListener
+  {
+    const inline_order_child = $('#inline_order_child');
+    const inline_order_parent = $('#inline_order_parent');
+    const order = [];
+
+    // Capture listener on parent
+    inline_order_parent.addEventListener('click', () => order.push('parent-capture'), true);
+
+    // Inline handler on child (should execute at target phase)
+    inline_order_child.onclick = () => order.push('child-onclick');
+
+    // addEventListener on child (should execute at target phase, after onclick)
+    inline_order_child.addEventListener('click', () => order.push('child-listener'));
+
+    // Bubble listener on parent
+    inline_order_parent.addEventListener('click', () => order.push('parent-bubble'));
+
+    inline_order_child.click();
+
+    // Expected order: capture, then onclick, then addEventListener, then bubble
+    testing.expectEqual('parent-capture', order[0]);
+    testing.expectEqual('child-onclick', order[1]);
+    testing.expectEqual('child-listener', order[2]);
+    testing.expectEqual('parent-bubble', order[3]);
+    testing.expectEqual(4, order.length);
+  }
+</script>
+
+<div id=inline_prevent><div id=inline_prevent_child></div></div>
+<script id=inlineHandlerPreventDefault>
+  // Test that inline handler can preventDefault and it affects addEventListener listeners
+  {
+    const inline_prevent_child = $('#inline_prevent_child');
+    let preventDefaultCalled = false;
+    let listenerSawPrevented = false;
+
+    inline_prevent_child.onclick = function(e) {
+      e.preventDefault();
+      preventDefaultCalled = true;
+    };
+
+    inline_prevent_child.addEventListener('click', (e) => {
+      listenerSawPrevented = e.defaultPrevented;
+    });
+
+    const result = inline_prevent_child.dispatchEvent(new MouseEvent('click', {
+      bubbles: true,
+      cancelable: true
+    }));
+
+    testing.expectEqual(true, preventDefaultCalled);
+    testing.expectEqual(true, listenerSawPrevented);
+    testing.expectEqual(false, result); // dispatchEvent returns false when prevented
+  }
+</script>
+
+<div id=inline_stop_parent><div id=inline_stop_child></div></div>
+<script id=inlineHandlerStopPropagation>
+  // Test that inline handler can stopPropagation
+  {
+    const inline_stop_child = $('#inline_stop_child');
+    const inline_stop_parent = $('#inline_stop_parent');
+    let childCalled = false;
+    let parentCalled = false;
+
+    inline_stop_child.onclick = function(e) {
+      childCalled = true;
+      e.stopPropagation();
+    };
+
+    inline_stop_parent.addEventListener('click', () => {
+      parentCalled = true;
+    });
+
+    inline_stop_child.click();
+
+    testing.expectEqual(true, childCalled);
+    testing.expectEqual(false, parentCalled); // Should not bubble to parent
+  }
+</script>
+
+<div id=inline_replace_test></div>
+<script id=inlineHandlerReplacement>
+  // Test that setting onclick property replaces previous handler
+  {
+    const inline_replace_test = $('#inline_replace_test');
+    let calls = [];
+
+    inline_replace_test.onclick = () => calls.push('first');
+    inline_replace_test.click();
+
+    inline_replace_test.onclick = () => calls.push('second');
+    inline_replace_test.click();
+
+    testing.expectEqual('first', calls[0]);
+    testing.expectEqual('second', calls[1]);
+    testing.expectEqual(2, calls.length);
+  }
+</script>

src/browser/tests/image_data.html

@@ -0,0 +1,75 @@
+<!DOCTYPE html>
+<script src="testing.js"></script>
+
+<script id=constructor-basic>
+  {
+    const img = new ImageData(10, 20);
+    testing.expectEqual(10, img.width);
+    testing.expectEqual(20, img.height);
+    testing.expectEqual("srgb", img.colorSpace);
+    testing.expectEqual("rgba-unorm8", img.pixelFormat);
+  }
+</script>
+
+<script id=data-property>
+  {
+    const img = new ImageData(2, 3);
+    const data = img.data;
+    testing.expectEqual(true, data instanceof Uint8ClampedArray);
+    // 2 * 3 * 4 (RGBA) = 24 bytes
+    testing.expectEqual(24, data.length);
+  }
+</script>
+
+<script id=data-initialized-to-zero>
+  {
+    const img = new ImageData(2, 2);
+    const data = img.data;
+    for (let i = 0; i < data.length; i++) {
+      testing.expectEqual(0, data[i]);
+    }
+  }
+</script>
+
+<script id=data-mutability>
+  {
+    const img = new ImageData(1, 1);
+    const data = img.data;
+    // Set pixel to red (RGBA)
+    data[0] = 255;
+    data[1] = 0;
+    data[2] = 0;
+    data[3] = 255;
+
+    // Read back through the same accessor
+    const data2 = img.data;
+    testing.expectEqual(255, data2[0]);
+    testing.expectEqual(0, data2[1]);
+    testing.expectEqual(0, data2[2]);
+    testing.expectEqual(255, data2[3]);
+  }
+</script>
+
+<script id=constructor-with-settings>
+  {
+    const img = new ImageData(5, 5, { colorSpace: "srgb" });
+    testing.expectEqual(5, img.width);
+    testing.expectEqual(5, img.height);
+    testing.expectEqual("srgb", img.colorSpace);
+  }
+</script>
+
+<script id=constructor-invalid-colorspace>
+  testing.expectError("TypeError", () => {
+    new ImageData(5, 5, { colorSpace: "display-p3" });
+  });
+</script>
+
+<script id=single-pixel>
+  {
+    const img = new ImageData(1, 1);
+    testing.expectEqual(4, img.data.length);
+    testing.expectEqual(1, img.width);
+    testing.expectEqual(1, img.height);
+  }
+</script>

src/browser/tests/intersection_observer/basic.html

@@ -25,6 +25,8 @@
         testing.expectEqual('number', typeof entry.intersectionRatio);
         testing.expectEqual('object', typeof entry.boundingClientRect);
         testing.expectEqual('object', typeof entry.intersectionRect);
+        testing.expectEqual('number', typeof entry.time);
+        testing.expectEqual(true, entry.time > 0);
 
         observer.disconnect();
     });

src/browser/tests/legacy/xhr/xhr.html

@@ -106,3 +106,17 @@
     testing.expectEqual(req5, target);
   })
 </script>
+
+<script id=xhr6 type=module>
+  const req5 = new XMLHttpRequest()
+  const promise5 = new Promise((resolve) => {
+    req5.onload = resolve;
+    req5.open('PROPFIND', 'http://127.0.0.1:9589/xhr')
+    req5.send('foo')
+  });
+
+  testing.async(promise5, () => {
+    testing.expectEqual(200, req5.status);
+    testing.expectEqual('OK', req5.statusText);
+    testing.expectEqual(true, req5.responseText.length > 65);
+  });

src/browser/tests/net/request.html

@@ -130,3 +130,10 @@
     testing.expectEqual("you", request2.headers.get("target"));
   }
 </script>
+
+<script id=propfind>
+  {
+    const req = new Request('https://example.com/api', { method: 'propfind' });
+    testing.expectEqual('PROPFIND', req.method);
+  }
+</script>

src/browser/tests/net/xhr.html

@@ -125,6 +125,26 @@
   })
 </script>
 
+<script id=xhr6>
+  const req6 = new XMLHttpRequest()
+  testing.async(async (restore) => {
+    await new Promise((resolve) => {
+      req6.onload = resolve;
+      req6.open('GET', 'http://127.0.0.1:9582/xhr/binary')
+      req6.responseType ='arraybuffer'
+      req6.send()
+    });
+
+    restore();
+    testing.expectEqual(200, req6.status);
+    testing.expectEqual('OK', req6.statusText);
+    testing.expectEqual(7, req6.response.byteLength);
+    testing.expectEqual([0, 0, 1, 2, 0, 0, 9], new Int32Array(req6.response));
+    testing.expectEqual('', typeof req6.response);
+    testing.expectEqual('arraybuffer', req6.responseType);
+  });
+</script>
+
 <script id=xhr_redirect>
   testing.async(async (restore) => {
     const req = new XMLHttpRequest();
@@ -202,3 +222,33 @@
     testing.expectEqual(XMLHttpRequest.UNSENT, req.readyState);
   });
 </script>
+
+<script id=xhr_abort_callback>
+  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');
+      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/child_nodes.html

@@ -22,6 +22,8 @@
   testing.expectEqual(undefined, children[-1]);
 
   testing.expectEqual(['p1', 'p2'], Array.from(children).map((n) => n.id));
+
+  testing.expectEqual(false, 10 in children);
 </script>
 
 <script id=values>

src/browser/tests/node/node.html

@@ -210,3 +210,28 @@
   testing.expectEqual('HTMLDivElement', disconnectedChild.getRootNode().__proto__.constructor.name);
   testing.expectEqual('HTMLDivElement', disconnectedChild.getRootNode({ composed: true }).__proto__.constructor.name);
 </script>
+
+<div id=contains><div id=other></div></div>
+<script id=contains>
+  {
+    const d1 = $('#contains');
+    const d2 = $('#other');
+    testing.expectEqual(false, d1.contains(null));
+    testing.expectEqual(true, d1.contains(d1));
+    testing.expectEqual(false, d2.contains(d1));
+    testing.expectEqual(true, d1.contains(d2));
+    testing.expectEqual(false, d1.contains(p1));
+  }
+</script>
+
+<script id=childNodes>
+  {
+    const d1 = $('#contains');
+    testing.expectEqual(true, d1.childNodes === d1.childNodes)
+
+    let c1 = d1.childNodes;
+    d1.removeChild(c1[0])
+    testing.expectEqual(0, c1.length);
+    testing.expectEqual(0, d1.childNodes.length);
+  }
+</script>

src/browser/tests/performance_observer/performance_observer.html

@@ -37,7 +37,6 @@
 }
 </script>
 
-<<<<<<< HEAD
 <script id="microtask_access_to_list">
 {
 
@@ -69,3 +68,31 @@
 <script>
   testing.expectEqual(['mark', 'measure'], PerformanceObserver.supportedEntryTypes);
 </script>
+
+<script id="buffered_option">
+{
+  // Clear marks from previous tests so we get a precise count
+  performance.clearMarks();
+
+  // Create marks BEFORE the observer
+  performance.mark("early1", { startTime: 1.0 });
+  performance.mark("early2", { startTime: 2.0 });
+
+  let receivedEntries = null;
+  const observer = new PerformanceObserver((list) => {
+    receivedEntries = list.getEntries();
+  });
+
+  // With buffered: true, existing marks should be delivered
+  observer.observe({ type: "mark", buffered: true });
+
+  testing.eventually(() => {
+    testing.expectEqual(true, receivedEntries !== null);
+    testing.expectEqual(2, receivedEntries.length);
+    testing.expectEqual("early1", receivedEntries[0].name);
+    testing.expectEqual("early2", receivedEntries[1].name);
+
+    observer.disconnect();
+  });
+}
+</script>

src/browser/tests/range.html

@@ -191,6 +191,74 @@
 }
 </script>
 
+<script id=toString_sameText>
+{
+  const p = document.createElement('p');
+  p.textContent = 'Hello World';
+
+  const range = document.createRange();
+  range.setStart(p.firstChild, 3);
+  range.setEnd(p.firstChild, 8);
+
+  testing.expectEqual('lo Wo', range.toString());
+}
+</script>
+
+<script id=toString_sameElement>
+{
+  const div = document.createElement('div');
+  div.innerHTML = '<p>First</p><p>Second</p><p>Third</p>';
+
+  const range = document.createRange();
+  range.setStart(div, 0);
+  range.setEnd(div, 2);
+
+  testing.expectEqual('FirstSecond', range.toString());
+}
+</script>
+
+<script id=toString_crossContainer_siblings>
+{
+  const p = document.createElement('p');
+  p.appendChild(document.createTextNode('AAAA'));
+  p.appendChild(document.createTextNode('BBBB'));
+  p.appendChild(document.createTextNode('CCCC'));
+
+  const range = document.createRange();
+  range.setStart(p.childNodes[0], 2);
+  range.setEnd(p.childNodes[2], 2);
+
+  testing.expectEqual('AABBBBCC', range.toString());
+}
+</script>
+
+<script id=toString_crossContainer_nested>
+{
+  const div = document.createElement('div');
+  div.innerHTML = '<p>First paragraph</p><p>Second paragraph</p>';
+
+  const range = document.createRange();
+  range.setStart(div.querySelector('p').firstChild, 6);
+  range.setEnd(div.querySelectorAll('p')[1].firstChild, 6);
+
+  testing.expectEqual('paragraphSecond', range.toString());
+}
+</script>
+
+<script id=toString_excludes_comments>
+{
+  const div = document.createElement('div');
+  div.appendChild(document.createTextNode('before'));
+  div.appendChild(document.createComment('this is a comment'));
+  div.appendChild(document.createTextNode('after'));
+
+  const range = document.createRange();
+  range.selectNodeContents(div);
+
+  testing.expectEqual('beforeafter', range.toString());
+}
+</script>
+
 <script id=insertNode>
 {
   const range = document.createRange();
@@ -743,11 +811,11 @@
   // range1 start is before range2 start
   testing.expectEqual(-1, range1.compareBoundaryPoints(Range.START_TO_START, range2));
 
-  // range1 start is before range2 end
-  testing.expectEqual(-1, range1.compareBoundaryPoints(Range.START_TO_END, range2));
-
   // range1 end is after range2 start
-  testing.expectEqual(1, range1.compareBoundaryPoints(Range.END_TO_START, range2));
+  testing.expectEqual(1, range1.compareBoundaryPoints(Range.START_TO_END, range2));
+
+  // range1 start is before range2 end
+  testing.expectEqual(-1, range1.compareBoundaryPoints(Range.END_TO_START, range2));
 
   // range1 end is before range2 end
   testing.expectEqual(-1, range1.compareBoundaryPoints(Range.END_TO_END, range2));
@@ -767,11 +835,11 @@
   testing.expectEqual(0, range.compareBoundaryPoints(Range.START_TO_START, range));
   testing.expectEqual(0, range.compareBoundaryPoints(Range.END_TO_END, range));
 
-  // Start is before end
-  testing.expectEqual(-1, range.compareBoundaryPoints(Range.START_TO_END, range));
-
   // End is after start
-  testing.expectEqual(1, range.compareBoundaryPoints(Range.END_TO_START, range));
+  testing.expectEqual(1, range.compareBoundaryPoints(Range.START_TO_END, range));
+
+  // Start is before end
+  testing.expectEqual(-1, range.compareBoundaryPoints(Range.END_TO_START, range));
 }
 </script>
 

src/browser/tests/selection.html

@@ -541,3 +541,55 @@
     testing.expectEqual(3, sel.focusOffset);
   }
 </script>
+
+<script id=selectionChangeEvent>
+  {
+    const sel = window.getSelection();
+    sel.removeAllRanges();
+
+    let eventCount = 0;
+    let lastEvent = null;
+
+    document.addEventListener('selectionchange', (e) => {
+      eventCount++;
+      lastEvent = e;
+    });
+
+    const p1 = document.getElementById("p1");
+    const textNode = p1.firstChild;
+    const nested = document.getElementById("nested");
+
+    sel.collapse(textNode, 5);
+    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();
+
+    testing.eventually(() => {
+      testing.expectEqual(14, eventCount);
+      testing.expectEqual('selectionchange', lastEvent.type);
+      testing.expectEqual(document, lastEvent.target);
+      testing.expectEqual(false, lastEvent.bubbles);
+      testing.expectEqual(false, lastEvent.cancelable);
+    });
+  }
+</script>

src/browser/tests/window/stubs.html

@@ -0,0 +1,34 @@
+<!DOCTYPE html>
+<script src="../testing.js"></script>
+
+<script id="alert">
+  {
+    // alert should be callable without error
+    window.alert('hello');
+    window.alert();
+    testing.expectEqual(undefined, window.alert('test'));
+  }
+</script>
+
+<script id="confirm">
+  {
+    // confirm returns false in headless mode
+    testing.expectEqual(false, window.confirm('proceed?'));
+    testing.expectEqual(false, window.confirm());
+  }
+</script>
+
+<script id="prompt">
+  {
+    // prompt returns null in headless mode
+    testing.expectEqual(null, window.prompt('enter value'));
+    testing.expectEqual(null, window.prompt('enter value', 'default'));
+    testing.expectEqual(null, window.prompt());
+  }
+</script>
+
+<script id="devicePixelRatio">
+  {
+    testing.expectEqual(1, window.devicePixelRatio);
+  }
+</script>