mgbrowser v0.9.31 Experimental Preview

mgbrowser v0.9.31 Experimental Preview

W3C Beacon (navigator.sendBeacon), WebIDL host method-override and expando
assignment semantics across navigator/console/history/DOM wrappers,
Navigation Timing (performance.timing & performance.navigation), ECMA-262
Annex B string/date compatibility (String.prototype.substr,
trimLeft/trimRight, Date.prototype.toGMTString), same-origin
iframe.contentWindow intrinsic constructors, and <noscript> fallback
projection when initial page scripts hit cooperative EngineLimit with zero
rendered items — resolving all JavaScript console errors and blank-screen traps
on Google Search (https://www.google.com/ -> /search?... ->
/httpservice/retry/enablejs with 0 diagnostics). Exact-source publication
and public-install receipts are recorded in the dated work log.

Linux x86_64 / X11 or XWayland, glibc 2.35 or newer. Rust 1.91.1, locked
dependencies, Apache-2.0 license, and pure-Rust implementation backends (zero
new crate dependencies).

Beacon API, WebIDL Method Overrides & Navigation Timing (v0.9.31)

• W3C navigator.sendBeacon(url, data?) (crates/mg-sparkle/src/js_browser/boa/web_apis.rs):
  • Brand-checks Navigator receivers (TypeError on unbound/alien this),
    resolves url against the document URL requiring http: or https:
    schemes (TypeError on invalid URLs or javascript:/data:/about:
    schemes), validates optional USVString, URLSearchParams, and
    BufferSource (ArrayBuffer, TypedArray, DataView) payloads, enforces
    the 64 KiB (65,536-byte) keepalive quota (false when exceeded, true
    within bounds), and exposes standard read-only Navigator properties
    (cookieEnabled, onLine, webdriver, pdfViewerEnabled, vendor,
    languages, maxTouchPoints, hardwareConcurrency).
• WebIDL Host Method Overrides & Expando Properties (crates/mg-sparkle/src/js_browser/boa.rs):
  • Distinguishes read-only IDL data attributes (such as navigator.userAgent,
    navigator.webdriver, document.nodeType, and event.type, which remain
    non-writable in sloppy and strict mode) from regular WebIDL operations and
    expandos across navigator, console, history, and DOM/event wrappers
    (preserving [LegacyUnforgeable] location restrictions and defineProperty
    wrapper invariants).
• Navigation Timing, Annex B & iframe.contentWindow Intrinsics (crates/mg-sparkle/src/js_browser/boa/):
  • Adds performance.timing (navigationStart, fetchStart, responseStart,
    domInteractive, domComplete, loadEventEnd, etc.) and
    performance.navigation (type, redirectCount, TYPE_* constants).
  • Registers ECMA-262 Annex B String.prototype.substr (UTF-16 code-unit
    slicing with negative start and Infinity/NaN handling),
    String.prototype.trimLeft / trimRight, and
    Date.prototype.toGMTString.
  • Populates same-origin iframe.contentWindow with standard realm
    constructors (Object, Array, String, Number, RegExp, Promise,
    Uint8Array, JSON, etc.) and platform globals (navigator,
    performance, screen).

Cooperative EngineLimit Empty-Projection <noscript> Fallback (v0.9.31)

• Blank-Screen Prevention on Challenge Pages (crates/mg-chassis/src/lib.rs):
  • When an initial page script realm hits cooperative RealmState::Fatal
    (OPCODE_LIMIT = 1_000_000) before revealing any body items
    (doc.items.is_empty()), mg-chassis checks whether the unscripted
    document provides <noscript> fallback items or a <meta http-equiv="refresh">
    target (refresh_count < 4) and adopts that fallback projection while
    preserving InitialScriptOutcome diagnostics, worker accounting, and
    ScriptWorkStatus::Blocked.
  • Note: Google's server-side SearchGuard (SG_SS / BotGuard) still redirects
    non-Chrome clients away from live SERP results; the full Google search
    destination goal remains incomplete and deferred as documented in
    AGENTS.md.

Preserved Resource & Isolation Profile

• All boa-page-process-v1 limits remain unchanged (OPCODE_LIMIT = 1_000_000,
  32 MiB outstanding / 64 MiB cumulative worker allocations, RLIMIT_NOFILE = 3,
  RLIMIT_FSIZE = 0, RLIMIT_CPU = 1, seccomp confinement, and < 8 MiB
  compressed release archive ceiling).
• Static WPT reftest coverage (558 PASS / 391 FAIL / 62 UNSUPPORTED of
  1,011) and Window WPT coverage (16/16 files, 79/79 final subtests)
  remain intact with zero regressions.