NOTE: This is a living document, it does not contain every difference currently and will be added to.

Neat site for checking the connection side of things (not sure of trustworthiness, take it with a grain of salt): https://cloudflare.manfredi.io/en/tools/connection/

• navigator.plugins is empty (presumably because we report no PDF support, see navigator.pdfViewerEnabled)

  navigator.mimeTypes is empty (presumably because we report no PDF support, see navigator.pdfViewerEnabled)

  Missing first-input performance entry type

  Missing paint performance entry type (including first-paint and first-contentful-paint)

  Missing navigation performance entry type

  Missing resource performance entry type (definitely needs implementing, disabling dom.enable_resource_timing in Firefox makes it never pass)

  Missing visibility-state performance entry type

  Missing long-animation-frame performance entry type

  Missing WEBGL_debug_renderer_info extension for unmasked vendor/renderer info

  Blob URLs for workers don't work, reporting DedicatedWorkerHost: Unable to fetch script blob:https://localhost:8080/c838e9e6-b238-4210-a349-9c909821d0a5 because script was null

  navigator.hardwareConcurrency always reports 1

  window.outerWidth and window.outerHeight report 0 (used in zoom calculation if it thinks we're chromium: Math.round((window.outerWidth / window.innerWidth) * 100) / 100)

  Thinks we're Firefox due to missing window.chrome and window.webkitRequestAnimationFrame, which makes it resort to probing min--moz-device-pixel-ratio via window.matchMedia for zoom calculation, and reporting "ff" in the same test

  typeof document.all is not "undefined"

  Missing screen.availTop

  Missing screen.availLeft

  Missing screen.orientation (angle, onchange, lock, unlock, type, inherits EventTarget)

  Missing screen.onchange

  Missing screen.isExtended

  Screen does not inherit EventTarget

  Missing OfflineAudioContext (random fingerprint challenge, see LibWeb: Implement OfflineAudioContext #224)

  This spec issue for WWW-Authenticate needs resolving:
  

  ladybird/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp

  Lines 1582 to 1583 in e800605

  	// 1. Needs testing: multiple `WWW-Authenticate` headers, missing, parsing issues.
  	// (Red box in the spec, no-op)

  This spin in execute_script causes the SubtleCrypto::digest task to run out of order in the layout fingerprint challenge, effectively causing an assertion failure in the Turnstile VM:
  

  ladybird/Userland/Libraries/LibWeb/HTML/HTMLScriptElement.cpp

  Lines 73 to 74 in e800605

  	if (!m_document->ready_to_run_scripts())
  	main_thread_event_loop().spin_until([&] { return m_document->ready_to_run_scripts(); });

  LibWeb: src-less iframes never become ready to run scripts SerenityOS/serenity#23836

  Canvas issues in fingerprinting: LibWeb: Discrepancies between Turnstile and other engines in canvas fingerprinting #225

  Assuming it scans all HTTP headers sent, we likely need to implement this:
  

  ladybird/Userland/Libraries/LibWeb/Fetch/Fetching/Fetching.cpp

  Line 1353 in e800605

  // FIXME: 13. Append the Fetch metadata headers for httpRequest.

  Additionally, the priority header, shipped in Firefox and Safari and soon for Chrome: https://chromestatus.com/feature/5109106573049856

  LibGfx: Unable to decode Cloudflare Turnstile PNGs that just contain width and height info SerenityOS/serenity#22869

  Missing HTMLScriptElement#async (7f0920b)

  Missing Document#lastModified

  Missing navigator.maxTouchPoints

  Missing AnalyserNode#getFloatTimeDomainData

  Missing AudioBuffer#copyFromChannel

  Missing HTMLCanvasElement#captureStream

  Missing AnalyserNode#maxDecibels

  Missing AnalyserNode#getByteTimeDomainData

  Missing CanvasRenderingContext2D#getLineDash

  Missing BiquadFilterNode#getFrequencyResponse

  Missing SVGTextContentElement#getExtentOfChar

  Missing OffscreenCanvasRenderingContext2D#isPointInStroke

  Missing Window.closed

  UIEvent.detail always reports 0 instead of the current click count

  MouseEvent.movementX and MouseEvent.movementY always reports 0

  Missing MouseEvent.relatedTarget

  Missing MouseEvent.layerX and MouseEvent.layerY

  click event doesn't dispatch a PointerEvent, but instead a MouseEvent, including synthetic clicks via Element#click (likely an issue for other events too)

  Missing PointerEvent and all of it's attributes and functions

  We don't set Event#timestamp, defaulted to 0 (at least for click event)

  <link rel="preload" as="..."> doesn't follow the spec at all, using ResourceLoader directly (missing fetch headers, missing window load event delay, etc.)

  Missing console.dirxml

  Missing console.table

  JSON.stringify(window.getComputedStyle(document.body)) returns {} instead of the serialization of all the properties and their values

  Missing WebGLRenderingContextBase.getParameter

  Missing WebGLRenderingContext2#bufferData()

  Missing WebGLRenderingContext2#readPixels()

  Content Security Policy
  To pick up a draggable item, press the space bar. While dragging, use the arrow keys to move the item. Press space again to drop the item in its new position, or press escape to cancel.

CSS and serialization via cssText:

• url() function serialize with the base URL of the origin, when it shouldn't, e.g. hosted on https://localhost:8080, this:
  To pick up a draggable item, press the space bar. While dragging, use the arrow keys to move the item. Press space again to drop the item in its new position, or press escape to cancel.

.OwaTZc4{background-image:url('/cdn-cgi/challenge-platform/h/b/cmg/1/hV7fTYrIy7e%2FC5FuCgYHr5Utjf5x6tY32TUpCSZd1P8%3D'); background-position: -1px -1px; background-repeat:no-repeat;}

Serializes as:

.OwaTZc4 { background-image: url(\"https://localhost:8080/cdn-cgi/challenge-platform/h/b/cmg/1/hV7fTYrIy7e%2FC5FuCgYHr5Utjf5x6tY32TUpCSZd1P8%3D\"); background-position: left -1px top -1px; background-repeat: no-repeat no-repeat; }

• Combined percentages in @keyframe are serialized separately instead of together, e.g.:
  To pick up a draggable item, press the space bar. While dragging, use the arrow keys to move the item. Press space again to drop the item in its new position, or press escape to cancel.

@keyframes scale {
    0%, 100% {
        transform: none;
    }
    50% {
	transform: scale3d(1, 1, 1);
    }
}

Should serialize as:

@keyframes scale { 
  0%, 100% { transform: none; }
  50% { transform: scale3d(1, 1, 1); }
}

But we serialize it as:

@keyframes "scale" {
    0% {
        transform: none;
    }

    100% {
        transform: none;
    }

    50% {
        transform: scale3d(1, 1, 1);
    }
}

• Fail to parse and serialize multiple animations declared in one animation property, e.g. animation: fillfail 0.4s ease-in-out 0.4s forwards, scale 0.3s ease-in-out 0.9s both;
• Some properties are serialized as full form when they shouldn't:

  • text-decoration: underline; -> text-decoration: underline auto solid currentcolor;
  • border-radius: 50%; -> border-radius: 50% 50% 50% 50% / 50% 50% 50% 50%;
  • animation: scale-up-center 0.6s cubic-bezier(0.55, 0.085, 0.68, 0.53) both; -> animation: cubic-bezier(0.55, 0.085, 0.68, 0.53) normal scale-up-center running 0s 0.6s both 1; (note that this is also serialized out of order)
  • background: #fff; -> background: rgb(255, 255, 255) none left 0% top 0% auto auto repeat repeat scroll padding-box border-box;
  • Weird one: flex-flow: column nowrap; (as specified in the actual style sheet) should serialize as flex-flow: column, but we keep it as is
  • Same with flex-flow: row nowrap; and flex-flow: row-reverse nowrap;

  To pick up a draggable item, press the space bar. While dragging, use the arrow keys to move the item. Press space again to drop the item in its new position, or press escape to cancel.
Missing stroke-dashoffset and it's serialization
Missing stroke-linecap and it's serialization
Missing stroke-miterlimit and it's serialization
Missing stroke-dasharray and it's serialization
Missing stroke-linejoin and it's serialization
This: