This is my selection of relevant Chromium and Firefox intents (from blink-dev and dev-platform@mozilla.org, respectively). Updated weekly.

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Chromium

November 2024

• 🆕 Prototype Subresource Reporting for scripts
• 🆕 Prototype Container Timing (incl. containertiming attribute)
• 🆕 Prototype and ship CSS scroll-start-target property
• 🆕 Prototype Camera Effect Status API

October 2024

• Prototype aria-actions attribute
• Prototype closedby attribute for HTML <dialog> element (light dismiss)
• Experiment keyboard-focusable scroll containers (cont.)
• Prototype CSS ::scroll-*-button pseudo-elements
• Prototype CSS ::column pseudo-element
• Prototype CSS Inertness
• Prototype "interrupted" state for AudioContext (Web Audio API)
• Experiment Translator API
• Ship sideways-rl and sideways-lr keywords for the CSS writing-mode property
• Ship beforetoggle and toggle events for the <dialog> element
• Experiment Summarizer API
• Ship CSS caret-animation property
• Ship CSS ::details-content pseudo-element and display property on <details>/<summary> elements
• Ship Device Posture API
• Prototype auto value for CSS view-transition-name property

September 2024

• Prototype Progress Notification API
• Prototype CSS :local-link pseudo-class
• Prototype CSS :has-slotted pseudo-class
• Experiment HTML <permission> element (Page-Embedded Permission Control) (cont.)
• Ship CSS @page margin boxes
• Prototype CSS stretch sizing keyword
• Ship currentcolor in relative color syntax
• Prototype CSS Custom Highlight highlightsFromPoint method
• Ship WebXR Hand Input module
• Ship CSS font-variant-emoji property
• Prototype Document-Policy expect-no-linked-resources configuration point
• Ship File System Access on Android and WebView
• Ship CSS box-decoration-break property (full support)
• Experiment fetchLater method (cont.)

August 2024

• Prototype Rewriter API
• Prototype Writer API
• Ship interoperable appearance: none fallback style for <meter> elements
• Experiment Language Detector API
• Experiment canvas 2D triangle mesh API (Mesh2D)
• Ship Direct Sockets API
• Experiment reduced Accept-Language header
• Ship scheduler.yield method
• Prototype CSS Gap Decoration
• Prototype dynamic import maps
• Prototype Summarizer API
• Ship preferInitialWindowPlacement option for Picture-in-Picture API
• Ship CSS nested declarations rules

July 2024

• Prototype HTML handwriting attribute
• Experiment FileSystemObserver API
• Prototype nested view transitions
• Prototype Sanitizer API
• Ship CSS interpolate-size property and calc-size() function
• Ship Isolated Web Apps
• Experiment partitioning :visited links history (phase 2)
• Prototype Selection API across Shadow DOM and getComposedRanges method

June 2024

• Prototype media-playback-while-not-rendered Permission Policy
• Prototype Canvas placeElement method
• Experiment Digital Credential API
• Prototype CSS box-decoration-break property (full support)
• Implement and ship HTML aria-rowindextext and aria-colindextext attributes
• Ship color-interpolation: linearrgb on SVG gradients
• Ship CSS ruby-align property
• Ship document.caretPositionFromPoint method
• Prototype sideways-rl and sideways-lr keywords for the CSS writing-mode property
• Prototype service worker auto preload
• Prototype CSS Masonry
• Experiment tabbed web apps (cont.)

May 2024

• Implement and ship line-breakable ruby (line-breaks within elements with display: ruby)
• Prototype CSS ruby-align property
• Ship CSS Snap Events (scrollsnapchange and scrollsnapchanging)
• Experiment Compression Dictionary Transport (cont.)
• Ship unrestricted WebUSB (for Isolated Web Apps with "usb-unrestricted" Permission Policy)
• Ship CSS anchor-scope property
• Prototype partitioned popins
• Experiment HTML <permission> element (Page-Embedded Permission Control)
• Ship CSS font-size-adjust property (new syntax)
• Ship alt text for the CSS content property (multiple arguments including attr() and counter())
• Prototype <link rel="payment"> hints for pending push payments
• Ship tabbed web apps (tabbed display mode)
• Prototype CSS highlight pseudos for find-in-page results
• Ship View Transitions in same-origin navigation (expands API to support MPAs)

April 2024

• Prototype alt text for the CSS content property (multiple arguments including attr() and counter())
• Prototype Web Translation API
• Prototype Storage Access API HTTP headers
• Ship URL.parse static method
• Ship CSS Anchor Positioning
• Prototype Web Install API
• Prototype HTML headingstart attribute
• Ship Declarative shadow DOM serialization
• Ship CSS round(), mod(), and rem() functions
• Prototype HTTP Document-Isolation-Policy header
• Prototype CSS ::scroll-marker and ::scroll-markers pseudo-elements
• Experiment Device Posture API and Viewport Segments Enumeration API

March 2024

• Ship CSS view-transition-class property
• Ship extending Storage Access API to non-cookie storage
• Ship HTML writingsuggestions attribute
• Prototype Playout Statistics API for WebAudio
• Experiment document.caretPositionFromPoint method
• Experiment extending Storage Access API to non-cookie storage (cont.)
• Experiment tabbed display mode for tabbed web apps (cont.)
• Ship Compute Pressure API
• Ship HTML <link rel=expect> element for document render-blocking
• Ship pageswap event

February 2024

• Prototype HTML interesttarget attribute for buttons and links
• Prototype CSS reading-order-items property
• Ship Sec-CH-UA-Form-Factor client hint
• Experiment <meta name="app-title"> and document.appTitle (document subtitle)
• Ship clonable option for attachShadow method, and shadowrootclonable attribute for <template> element
• Ship setHTMLUnsafe and parseHTMLUnsafe methods
• Ship HTTP Priority request header
• Ship picture-in-picture value for CSS display-mode media feature
• Prototype CSS functions (@function)
• Ship Content-Encoding: zstd (Zstandard data compression mechanism)
• Ship CSS paint-order property for HTML text
• Prototype picture-in-picture value for CSS display-mode media feature
• Ship ServiceWorker static routing API
• Prototype CSS :open and :closed pseudo-classes
• Prototype CSS line-clamp property
• Prototype and ship CSS zoom property
• Ship pagereveal event
• Prototype pageconceal event
• Prototype Web Monetization

January 2024

• Ship CSS text-spacing-trim property
• Ship element reflection for ARIA relationship attributes
• Ship CSS light-dark() function
• Prototype ShadowRoot clonable property
• Ship navigation.activation object
• Prototype HTML writingsuggestions attribute
• Prototype CSS text-box-trim and text-box-edge properties
• Prototype delayed clipboard rendering
• Prototype CSS view-transition-class property (styling of view transition pseudo-elements)
• Prototype Declarative shadow DOM serialization
• Prototype document.caretPositionFromPoint method
• Implement and ship HTML blocking=render attribute on inline <script> elements
• Implement and ship CSS display: contents not affecting fosucability
• Ship 'json' and 'css' request destinations for JSON and CSS modules
• Ship inheritance to CSS ::backdrop pseudo-element from its originating element

December 2023

• Prototype CSS calc-size() function
• Ship CSS field-sizing property
• Prototype fenced frames with local unpartitioned data access
• Prototype Locked Mode API
• Prototype CSS cross-fade() function
• Experiment Compute Pressure (cont.)
• Ship interoperable mousemove default action

November 2023

• Ship auto sizes for lazy-loaded images
• Ship multiple readers/writers in File System Access API
• Ship unsanitized option for the navigation.clipboard.read method
• Experiment ServiceWorker Static Routing API (cont.)
• Experiment Element Capture
• Ship improved CSS masking for SVG
• Trial HTML <permission> element (Page-Embedded Permission Control)
• Experiment fetchLater method
• Ship conditional @import supports() rules
• Ship Storage Buckets API
• Prototype snapchanging event (CSS scroll snap)
• Ship HTTP Speculation-Rules header
• Prototype navigation.activation object
• Ship animation behavior for the CSS font-palette property
• Ship contentVisibilityAuto option for checkVisibility method
• Prototype passkeys in cross-origin iframes
• Deprecate and remove third-party cookies
• Prototype CSS @page margin boxes
• Prototype contentVisibilityAuto option for checkVisibility method

October 2023

• Ship EditContext API
• Ship CSS ::spelling-error and ::grammar-error pseudo-elements, and spelling-error and grammar-error values for text-decoration-line
• Ship inheritance for the CSS ::selection and ::highlight pseudo-elements
• Ship CSS mask-* properties
• Ship Permissions policy violation reports
• Ship WebGPU on Android
• Experiment extending Storage Access API to non-cookie storage
• Ship ruby, ruby-base, and ruby-text values for CSS display property
• Ship CSS scrollbar-color and scrollbar-width properties
• Ship CSS <transform-function> and <transform-list> syntax for registered custom properties
• Prototype Web Printing API
• Ship CSS pow(), sqrt(), hypot(), log(), and exp() functions
• Prototype Invokers
• Prototype and ship URL.canParse method
• Experiment peformance.measureUserAgentSpecificMemory method
• Experiment web app manifest "scope_extensions" member
• Experiment HTTP Priority request header
• Ship CSS :dir() pseudo-class
• Ship relaxed CSS Nesting
• Implement and ship video <source media> attribute
• Ship HTMLSelectElement showPicker method
• Ship CSS <image> syntax for registered custom properties
• Prototype CSS Masking
• Prototype extending Storage Access API to non-cookie storage

September 2023

• Prototype Face Framing API
• Prototype Observable API
• Prototype firstrender event
• Prototype Device Bound Session Credentials (DBSC)
• Ship Intersection Observer scrollMargin property
• Ship accordion pattern using name attribute on <details> elements
• Ship Close Watchers
• Experiment fullscreen option for window.open method
• Prototype HTML exportid attribute (exporting IDs from shadow roots for cross-root ARIA)
• Ship <hr> elements inside <select> elements
• Implement and ship feature detection for supported clipboard formats
• Prototype showPicker method for HTML <select> elements
• Ship TLS Encrypted Client Hello (ECH)
• Prototype and ship xywh() and rect() for CSS clip-path property
• Prototype CSS dynamic-range-limit property
• Prototype Intersection Observer scrollMargin property
• Experiment partitioning :visited links history
• Experiment HTTP Speculation-Rules header (cont.)
• Prototype HTTP Sec-CH-UA-Form-Factor Header (client hint)
• Prototype Web Preferences API

August 2023

• Ship CSS Relative Color Syntax (from keyword)
• Prototype CSS form-sizing property
• Ship HTTP Sec-CH-Prefers-Reduced-Transparency header (client hint)
• Ship CSS word-break: auto-phrase value (more natural line breaking for Japanese)
• Prototype HTML <permission> element (Page-Embedded Permission Control)
• Ship CSS :user-valid and :user-invalid pseudo-classes
• Ship CSS scripting media feature
• Prototype CSS text-spacing-trim property
• Prototype CSS Sticky State Container Queries (stuck)
• Prototype CSS scripting media feature
• Implement and ship crossorigin attribute for SVG <image> and <feImage> elements
• Ship hasUAVisualTransition property for popstate and navigate events
• Prototype snapchanged event
• Ship HTML <search> element
• Deprecate Sanitizer API (initial impl.)
• Prototype HTML blocking="render" attribute
• Ship wertical writing modes (vertical-rl, vertical-lr) for form control elements
• Prototype and ship <geometry-box> in CSS clip-path property value
• Ship CSS cap and rcap units
• Ship Storage Access API with prompts
• Ship CSS logical values for float, clear, and resize properties

July 2023

• Experiment ServiceWorker Static Routing API
• Prototype CSS inverted-colors media feature
• Prototype fetchLater method
• Ship CSS prefers-reduced-transparency media feature
• Prototype HTTP Sec-CH-Prefers-Reduced-Transparency header
• Prototype and ship HTTP Clear-Site-Data: "*" header (clear all storage targets)
• Experiment web app manifest "tab_strip" member and "display_override": ["tabbed"] (tabbed web apps)
• Prototype Element Capture
• Experiment Content-Encoding: zstd (Zstandard data compression mechanism)
• Prototype CSS text-autospace property
• Ship back/forward cache (BFCache) for pages with HTTP Cache-control: no-store header
• Prototype CSS prefers-reduced-transparency media feature
• Prototype CSS font-variant-emoji property
• Ship stroke-box, content-box, and border-box values for CSS transform-box property
• Prototype CSS word-break: auto value (more natural line breaking for Japanese)
• Ship NotRestoredReasons API (back/forward cache)

June 2023

• Ship Permissions Policy "unload" feature
• Prototype partitioning :visited links history
• Prototype Storage Access API with prompts
• Prototype FileSystemObserver API
• Ship CSS text-wrap: pretty keyword
• Ship Shared Storage API
• Ship CSS @starting-style rule
• Prototype Content-Encoding: zstd (Zstandard data compression mechanism)
• Ship Fenced Frames
• Ship CSS subgrid layout
• Experiment EditContext API
• Ship customElements.getName method
• Prototype customElements.getName method
• Experiment scheduler.yield method
• Ship Document Picture-in-Picture
• Prototype DOM Parts
• Prototype ServiceWorker Static Routing API

May 2023

• Prototype auto sizes for lazy-loaded images
• Ship CSS @scope rule
• Experiment 'long-animation-frame' performance entry type
• Trial web app manifest "scope_extensions" member
• Deprecate Mutation Events
• Ship CSS Motion Path
• Deprecate unload event
• Trial Pending Beacon API (cont.)
• Prototype CSS scroll-start property
• Prototype Exclusive Accordion using <details> elements
• Ship boolean context style container queries

April 2023

• Ship scroll-driven animations
• Experiment Storage Buckets API
• Ship keyboard-focusable scroll containers
• Experiment Compute Pressure
• Ship CSS overlay property
• Ship multi-keyword values for the CSS display property
• Trial Controlled Frame API for Isolated Web Apps
• Prototype CSS display property (new two-value syntax)
• Trial fullscreen popup windows
• Ship partitioned storage, service workers, and communication APIs in third-party contexts
• Trial scheduler.yield method
• Ship Local Network Access

March 2023

• Implement and ship RegExp v flag for HTML pattern attribute
• Ship scrollend event type
• Prototype Document Subtitle (<meta name="subtitle"> and document.subtitle)
• Prototype CSS font-size-adjust property (new syntax)
• Ship requestStorageAccessFor method for First-Party Sets
• Ship Storage Access API within First-Party Sets
• Ship First-Party Sets
• Prototype animation behavior for the CSS font-palette property
• Ship CSS :lang pseudo-class
• Ship CSS transitions of discrete properties
• Ship CSS display and content-visibility in animations
• Ship Popover API
• Prototype Popover API popover=hint attribute value
• Prototype CSS text-box-trim property
• Prototype Screen-Capture Mouse Events

February 2023

• Ship CSS text-wrap property
• Ship CSS overflow-inline and overflow-block media features
• Ship CSS linear() easing function
• Ship CSS update media feature
• Ship CSS font-variant-position property
• Prototype CSS linear() easing function
• Experiment service worker fetch fast-path for main resources
• Trial Popover API (cont.)
• Prototype CSS text-wrap: balance keyword
• Prototype CSS top-layer property
• Prototype CSS :initial pseudo class
• Prototype Permissions Policy "battery" token

January 2023

• Prototype Controlled Frame API for Isolated Web Apps
• Ship CSS animation-composition property
• Prototype CSS user-select: contain keyword
• Experiment Permission Policy unload permission (cont.)
• Ship expanded CSS font shorthand
• Ship updated <dialog> initial focus algorithm
• Ship View Transitions for single-page apps
• Ship streaming declarative shadow DOM
• Ship CSS Nesting
• Experiment Back/forward cache NotRestoredReason API (cont.)
• Prototype CSS abs() and sign() functions
• Ship selector argument in CSS :nth-child() and :nth-last-child() pseudo-classes (An+B of S)
• Ship CSS baseline-source property
• Prototype WebXR Front-facing Camera API
• Experiment Document Picture-in-Picture
• Ship CSS rex, rch, ric, and rlh units
• Prototype HTTP Priority request header
• Prototype fullscreen popup windows (for Multi-Screen Window Placement)

December 2022

• Trial Compute Pressure
• Trial WebGPU (cont.)
• Prototype Gamepad multitouch extension
• Ship WebGPU
• Ship CSS container style queries for custom properties
• Ship CSS trigonometric functions (sin(), cos(), tan(), asin(), acos(), atan(), atan2())
• Prototype CSS baseline-source property
• Prototype streaming declarative shadow DOM
• Trial Popover API (cont.)
• Prototype CSS Transitions on specified discrete properties
• Prototype PointerEvent deviceId property for mult-pen inking
• Prototype HTTPS Upgrade
• Ship CSS font-variant-alternates property and @font-feature-values rule
• Prototype Additional Windowing Controls
• Trial First-Party Sets
• Prototype CSS display and content-visibility in animations
• Ship Network State Partitioning
• Trial Pending Beacon API (cont.)
• Ship IDNA 2008 in Non-Transitional Mode for URL processing

November 2022

• Ship CSS initial-letter property
• Experiment CSS initial-letter property
• Ship Permission Policty web-share permission
• Prototype inactive document invalidation API (for invalidating documents from BFCache or prerendering)
• Prototype Incoming Call Notifications
• Prototype WebSockets over HTTP/3
• Prototype View Transitions for single-page apps
• Experiment web app manifest "user_preferences" field (allows specifying dark mode colors) (updated)

October 2022

• Prototype scheduler.yield method
• Ship anonymous iframes
• Prototype HTTP Speculation-Rules header
• Experiment reduced information in HTTP Accept-Language header and navigator.languages property
• Ship CSS hyphenate-limit-chars property
• Experiment Back/forward cache NotRestoredReason API
• Ship Web App Launch Handling ("launch_handler")
• Ship Cookies Having Independent Partitioned State (CHIPS)
• Prototype URLPatternList
• Ship CSS color() and color-mix() functions, and other Color Level 4 additions
• Prototype CSS hyphenate-limit-chars property
• Prototype CSS initial-letter property
• Ship CSS lh unit
• Ship same-site (cross-origin) prerendering triggered by the speculation rules API
• Ship Conditional Focus
• Trial Page Unload Beacon API (PendingBeacon)
• Trial partitioning Storage, Service Workers, and Communication APIs
• Ship last baseline alignment for flex/grid items
• Ship Federated Credential Management API (was WebID)
• Experiment Private Aggregation API
• Experiment Network State Partitioning
• Prototype CSS Nesting

September 2022

• Implement and ship TrustedHTML fromLiteral method
• Ship URLPattern ignoreCase option
• Ship CSS small, large, dynamic, and logical viewport units
• Ship Origin Private File System on Android
• Prototype Web Smart Card API
• Ship CSS @supports font-tech() and @supports font-format() rules
• Experiment Permission Policy unload permission
• Ship WebAuthn Conditional UI
• Experiment Conditional Focus (cont.)
• Trial WebAuthn Conditional UI
• Prototype last baseline alignment for flex/grid items
• Ship HTTP Sec-CH-Prefers-Reduced-Motion header (client hint)
• Ship variations in COLRv1
• Prototype CSS lh unit
• Trial Permission Policy unload permission
• Prototype Bounce Tracking Mitigations
• Prototype same-site (cross-origin) prerendering triggered by the speculation rules API
• Ship HTML aria-brailleroledescription and aria-braillelabel attributes

August 2022

• Ship tech() function for CSS @font-face src descriptor
• Ship AudioContext setSinkId method
• Prototype Scoped Custom Element Registries
• Implement and ship rich PWA installation dialogs (description and screenshots) on desktop
• Ship same-origin prerendering triggered by the speculation rules API on desktop
• Experiment TLS Encrypted Client Hello (ECH)
• Ship contentvisibilityautostatechanged event
• Experiment Cookies Having Independent Partitioned State (CHIPS) (cont.)
• Prototype requestStorageAccessForSite API
• Ship CSS ic unit
• Experiment Pop-Up API (HTML popup attribute)
• Experiment Web App Launch Handling (cont.)
• Prototype and ship Client Hints in Android WebView
• Experiment LazyEmbeds (cont.)

July 2022

• Prototype URLPattern ignoreCase option
• Experiment Cross-Origin-Opener-Policy restrict-properties value
• Experiment anonymous iframes
• Prototype borderless display mode for installed web apps on desktop
• Trial WebGPU (cont.)
• Ship NavigateEvent scroll method
• Experiment web app manifest "user_preferences" field (allows specifying dark mode colors) (cont.)
• Prototype Custom Highlight API pointer events
• Ship fetch() upload streaming
• Prototype contentvisibilityautostatechanged event
• Ship CSS overflow property for replaced elements

June 2022

• Ship Viewport Height Client Hint (Sec-CH-Viewport-Height)
• Ship import.meta.resolve function
• Prototype renderBlockingStatus property for performance resource entries
• Ship MathML
• Prototype CSS overflow property for replaced elements
• Prototype requestPermission function for DeviceOrientationEvent and DeviceMotionEvent
• Experiment LazyEmbeds
• Prototype CSS trigonometric functions (sin(), cos(), tan(), asin(), acos(), atan(), atan2())
• Ship Picture-in-Picture on Android
• Experiment Declarative Beacon API (PendingBeacon)
• Experiment Shared Storage API
• Experiment Web App Launch Handling ("launch_handler" member) (cont.)
• Experiment Shared Element Transitions
• Ship Custom Highlight API
• Prototype CSS :lang() pseudo-class level 4 extension (argument lists and language range matching)
• Prototype wide-gamut colors in CSS
• Ship Sanitizer API (initial impl.)

May 2022

• Prototype tabbed web apps (tabbed display mode)
• Prototype Origin-Bound Cookies
• Ship CSS :modal pseudo-class
• Experiment Cookies Having Independent Partitioned State (CHIPS) (cont.)
• Trial subresource loading with Web Bundles (cont.)
• Ship HTML blocking=render attribute for <link> and <script> elements
• Ship CSS object-view-box property
• Ship CSS :has() pseudo-class
• Experiment HTML focusgroup attribute
• Prototype CSS Anchor Positioning
• Prototype Permission Policy unload feature
• Ship CSS Container Queries
• Prototype NotRestoredReason API (back/forward cache)
• Prototype PendingBeacon API
• Prototype Private Aggregation API
• Ship Element isVisible method
• Ship HTML <form rel> attribute
• Prototype and ship CSS overflow-clip-margin: <visual-box> values
• Experiment web app manifest "user_preferences" field (cont.)

April 2022

• Experiment Fenced Frames
• Experiment Web App Launch Handling (incl. web app manifest "launch_handler" member) (cont.)
• Prototype Element isVisible method
• Trial HTML focusgroup attribute
• Ship AbortSignal.timeout static method
• Ship Permissions Policy "gamepad" token
• Ship same-origin prerendering triggered by the speculation rules API
• Implement and ship Fullscreen Capability Delegation
• Ship HTTP status code 103 Early Hints on navigation responses
• Prototype and ship Permissions Policy "bluetooth" token
• Prototype Isolated Web Apps
• Ship SerialPort forget method
• Ship Navigation API
• Ship subresource loading with Web Bundles
• Ship Media Queries Level 4 syntax and evaluation (incl. range context)
• Ship Speculation Rules
• Prototype CSS Toggles
• Ship File Handling (web app manifest "file_handlers" field
• Ship Local Font Access API
• Experiment HTTP Sec-CH-Viewport-Height header (viewport height client hint)
• Experiment Network State Partitioning (cont.)
• Experiment same-origin prerendering triggered by the speculation rules API (cont.)

March 2022

• Experiment Attribution Reporting
• Prototype CSS @scope at-rule
• Prototype NotRestoredReason API (related to back/forward cache)
• Prototype Range API innerText property and adjust method
• Ship sync Access Handles for Origin Private File System
• Trial WebGPU (cont.)
• Experiment Federated Credentials Management (cont.)
• Ship HTML hidden=until-found attribute and beforematch event
• Prototype and ship CSS font-palette property and @font-palette-values at-rule
• Ship Capture Handle
• Ship Sec-CH-Save-Data client hint
• Prototype CSS object-view-box and object-overflow properties
• Ship Priority Hints (HTML fetchpriority attribute, and priority option for fetch)

February 2022

• Prototype Topics API
• Ship USBDevice forget method
• Ship Multi-Screen Window Placement
• Ship autofill in shadow DOM
• Trial Federated Credential Management API (was WebID)
• Ship omnibox prerendering
• Deprecate and remove Event path method
• Ship HIDDevice forget method
• Ship CSS hwb() color function
• Ship Network State Partitioning
• Experiment Cookies Having Independent Partitioned State (CHIPS)

January 2022

• Prototype Notification API for Confirmation of Action
• Implement overlay scrollbars on Windows (Microsoft Fluent Design System)
• Prototype AbortSignal.timeout static method
• Experiment Speculation Rules (cont.)
• Ship Web NFC makeReadOnly method (for locking NFC tags)
• Prototype Document Picture-in-Picture
• Prototype CSS subgrid layout
• Experiment Storage Foundation API (cont.)
• Experiment AccessHandle for File System Access API (cont.)
• Ship CSS mix-blend-mode: plus-lighter value
• Prototype HTML focusgroup attribute
• Prototype service worker registration id property
• Ship Handwriting Recognition API

December 2021

• Experiment Handwriting Recognition API (cont.)
• Prototype CSS mix-blend-mode: plus-lighter value
• Experiment same-origin prerendering triggered by the speculation rules API (cont.)
• Ship HTMLInputElement showPicker method
• Ship CSS @layer rule (Cascade Layers)
• Ship Handwriting Recognition API
• Experiment web app manifest "user_preferences" field (allows specifying dark mode colors)
• Prototype Machine Learning Model Loader API
• Prototype Web Neural Network API
• Prototype mirroring the web page on a secondary display via the Presentation API

November 2021

• Prototype High Dynamic Range (HDR) content in <canvas>
• Prototype dark mode colors in web app manifest
• Ship pickling for Async Clipboard API
• Prototype HTML blocking=render attribute for <link> and <script> elements
• Ship 'popup' option (window feature) for window.open()
• Ship AudioContext outputLatency property
• Prototype Fragment Directive API (for scroll-to-text)
• Prototype HTMLInputElement showPicker method
• Trial WebGPU (cont.)

October 2021

• Prototype and ship structuredClone function
• Ship CSS forced-color-adjust: preserve-parent-color value
• Ship auto keyword for CSS contain-intrinsic-size property
• Ship only keyword for CSS color-scheme property
• Trial subresource loading with Web Bundles (cont.)
• Experiment web app manifest "launch_handler" member
• Prototype web app manifest "translations" member
• Ship CSS dynamic-range and video-dynamic-range media features (HDR)
• Ship Window Controls Overlay for Installed Desktop Web Apps
• Trial WebTransport over HTTP/3 (cont.)
• Ship COLRv1 Color Gradient Vector Fonts
• Ship CSS translate, scale, and rotate properties (individual transforms)
• Implement and ship keyboard-map feature policy
• Ship updated Canvas 2D API
• Ship sec-ch- on all Client Hints
• Ship App Icon Shortcuts Menu on Mac and Linux
• Experiment only keyword for CSS color-scheme property
• Experiment HTTP status code 103 Early Hints on navigation responses (cont.)
• Ship CSS font-synthesis property
• Implement and ship no preflight for requests with simple Range header values
• Prototype web app manifest "scope_extensions" field
• Prototype web app manifest "handle_links" field

September 2021

• Ship WebTransport over HTTP/3
• Ship URL Protocol Handler Registration for PWAs
• Experiment Storage Foundation API (cont.)
• Ship web app manifest "id" field
• Experiment App History API
• Ship HTMLScriptElement supports method
• Experiment Trust Token API (cont.)
• Experiment FocusableMediaStreamTrack subclass (Conditional Focus)
• Prototype FocusableMediaStreamTrack subclass (Conditional Focus)
• Prototype HTML renderpriority attribute
• Prototype CSS font-synthesis property
• Ship auto-expanding <details> elements
• Ship speak-as descriptor for CSS @counter-style rule
• Experiment Priority Hints
• Trial updated Canvas 2D API (cont.)
• Experiment Speculation Rules (<script type="speculationrules">) (cont.)
• Experiment HTML importance attribute (Priority Hints) (cont.)
• Trial web app manifest "id" field
• Trial HTMLScriptElement supports method
• Prototype HTMLScriptElement supports method

August 2021

• Ship URLPattern API
• Experiment Shared Element Transitions (cont.)
• Ship reportError function
• Experiment Declarative Link Capturing for PWAs (cont.)
• Experiment Handwriting Recognition API (cont.)
• Experiment Capture Handle (cont.)
• Ship back-forward cache (BFCache) on desktop
• Trial subresource loading with Web Bundles (cont.)
• Experiment same-origin prerendering triggered by the Speculation Rules API
• Ship Custom Highlight API
• Ship EyeDropper API
• Prototype CSS math generic font family
• Trial AccessHandle for File System Access API
• Prototype CSS Cascade Layers
• Prototype AccessHandle for File System Access API
• Ship CSS prefers-contrast media feature
• Prototype Web App Launch Handling ("launch_handler" member)

July 2021

• Ship JS Self-Profiling API
• Ship Idle Detection API
• Ship Virtual Keyboard API
• Experiment HTTP Service-Worker-Subresource-Filter header
• Ship preferCurrentTab option for getDisplayMedia method (Screen Capture)
• Ship display-capture permission
• Experiment URLPattern API
• Prototype speak-as descriptor for CSS @counter-style rule
• Ship CSS @counter-style rules in shadow trees
• Experiment Window Controls Overlay for Installed Desktop Web Apps
• Experiment Device Attributes API
• Ship CSS scrollbar-gutter property
• Ship Web App Manifest "note_taking" field
• Experiment Conversion Measurement API (cont.)
• Experiment reduced User-Agent string
• Experiment Progressive Web Apps as URL Handlers
• Ship Prioritized Task Scheduling (scheduler.postTask method)
• Prototype Cookies Having Independent Partitioned State (CHIPS)
• Prototype Shared Storage API

June 2021

• Experiment Multi-Screen Window Placement
• Experiment Virtual Keyboard API
• Ship cross-device support for Web OTP API
• Ship supports <font-technology> for the CSS src descriptor
• Ship WebCodecs
• Prototype nad ship <meta name="theme-color" media> attribute
• Prototype Web App Manifest "id" field
• Ship HTTP Sec-CH-Prefers-Color-Scheme header (Client Hints)
• Ship Canvas color management (colorSpace option for canvas context)
• Ship CSS accent-color property
• Ship CSS module scripts
• Experiment URL Protocol Handler Registration for PWAs
• Prototype and ship AbortSignal abort static method
• Experiment WebCodecs (cont.)
• Implement and ship CSS :autofill pseudo-class

May 2021

• Experiment Speculation Rules (<script type="speculationrules">)
• Prototype and ship noplaybackrate token for the HTML media element controlslist attribute
• Experiment HTML aria-touchpassthrough attribute
• Prototype anonymous iframes
• Experiment HTTP status code 103 Early Hints on navigation responses
• Prototype HTTP Sec-CH-Prefers-Color-Scheme header (Client Hints)
• Experiment fetch() upload streaming (cont.)
• Prototype Pickling for Async Clipboard API
• Prototype CSS :has() pseudo-class
• Experiment Storage Foundation API (cont.)
• Experiment Capture Handle
• Prototype Capture Handle
• Experiment Shared Element Transitions
• Ship CSS size-adjust descriptor
• Experiment Digital Goods API (cont.)
• Ship EXIF-based intrinsic image sizing
• Ship crypto.randomUUID method
• Experiment Idle Detection API (cont.)
• Experiment Compute Pressure API
• Experiment WebGPU

April 2021

• Prototype Fenced Frames (for ads)
• Experiment First-Party Sets and SameParty cookie attribute (cont.)
• Experiment back-forward cache on desktop
• Experiment Trust Token API (cont.)
• Experiment updated Canvas 2D API
• Prototype HTTP Service-Worker-Subresource-Filter header
• Implement and ship tainted origin flag for fetch requests
• Experiment Network State Partitioning
• Implement and ship CSS :playing and :paused pseudo-classes
• Experiment WebTransport over HTTP/3
• Prototype CSS contain-intrinsic-size: auto value
• Ship imperative slot distribution API (Shadow DOM)

March 2021

• Ship Managed Configuration API
• Prototype Compute Pressure
• Prototype JPEG XL image format
• Ship HTML inert attribute
• Ship cross-origin iframe support in Web OTP API
• Experiment File Handling API
• Prototype Web App Manifest "note_taking" and "new_note_url" fields
• Prototype Lock Screen API
• Experiment Sanitizer API
• Ship GravitySensor API
• Experiment Handwriting Recognition API
• Experiment WebCodecs (cont.)
• Prototype and ship standard JavaScript modules in service workers
• Experiment subresource loading with Web Bundles
• Ship HTTP Critical-CH response header
• Implement and ship HTML <link rel="icon" media> attribute
• Experiment Federated Learning of Cohorts (FLoC)
• Prototype App History API
• Prototype document.prerendering property

February 2021

• Ship CSS advance-override descriptor
• Ship CSS @counter-style at-rule
• Prototype HTTP status code 103 Early Hints on navigation responses
• Ship Declarative Shadow DOM
• Prototype Speculation Rules
• Ship files on the clipboard
• Prototype Custom Highlight API
• Experiment Storage Foundation API
• Experiment First-Party Sets and SameParty cookie attribute
• Prototype CSS accent-color property
• Experimenrt QuicTransport (cont.)
• Ship stricter mixed content check for blob: and filesystem: URLs
• Prototype MulticastReceiver API
• Experiment Declarative Link Capturing for PWAs ("capture_links" member for web app manifest)

January 2021

• Ship CSS :focus-visible in the user-agent style sheet
• Ship signal option for addEventListener method (AbortSignal)
• Prototype Multi-Screen Window Placement
• Prototype Multi Apps
• Prototype ARIA Virtual Content
• Prototype GravitySensor API
• Prototype COLRv1 Color Gradient Vector Fonts
• Implement and ship StaticRange constructor
• Experiment Idle Detection API (cont.)
• Prototype HTML <popup> element
• Implement and ship smooth interpolation when animating the CSS aspect-ratio property
• Experiment scheduler.postTask method for main-thread scheduling (cont.)
• Prototype SameParty cookie attribute
• Experiment fetch() upload streaming
• Experiment Declarative Shadow DOM (cont.)
• Experiment Conversion Measurement API (cont.)
• Prototype CSS ::spelling-error and ::grammar-error pseudo-elements, and spelling-error and grammar-error values for text-decoration-line
• Ship performance.measureMemory method
• Spec, implement and ship persistent guaranteed-invalid CSS variables
• Implement Web Share API on macOS

December 2020

• Ship CSS filter property for SVG elements (filter functions)
• Implement and ship CSS :link, :visited, and :any-link pseudo selectors for <link> elements
• Prototype Declarative Link Capturing for PWAs ("capture_links" member for web app manifest)
• Prototype EyeDropper API
• Ship Web NFC
• Prototype well-specified prerendering
• Prototype infinity and NaN values in CSS calc()
• Prototype and ship CSS ::file-selector-button pseudo-element
• Ship Import Maps
• Ship Byte Streams (Streams API)
• Ship Web Serial API
• Prototype Canvas Formatted Text
• prototype and ship CSS border-start-start-radius, border-start-end-radius, border-end-start-radius, and border-end-end-radius properties
• Ship potentially trustworthy data: URLs
• Ship Web App Manifest "display_override" field
• Ship CSS overflow: clip value and overflow-clip-margin property
• Ship WebHID
• Ship disclosure-open and disclosure-closed keywords for the CSS list-style-type property
• Ship CSS list-style-type and ::marker support on <summary> element

November 2020

• Prototype Screen Fold API
• Prototype Handwriting Recognition API
• Prototype "display-capture" permission
• Experiment beforematch event and CSS content-visibility: hidden-matchable value (cont.)
• Ship CSS ::target-text pseudo-element
• Experiment WebCodecs (cont.)
• Prototype Shared Element Transitions
• Ship Origin Isolation
• Prototype signal option for addEventListener method (AbortSignal)
• Prototype CSS @counter-style at-rule
• Experiment HTML <meta name="battery-savings"> tag (cont.)
• Prototype Container Queries
• Ship click, contextmenu, and auxlick as instances of PointerEvent

October 2020

• Prototype NativeIO storage API
• Prototype WebXR Hand Input module
• Ship implicit rel="noopener" for <a target="_blank"> elements
• Prototype Capability Delegation
• Prototype byte streams for Streams API
• Implement and ship selector lists in CSS :not() pseudo-class
• Experiment Trust Token API (cont.)
• Prototype URL pattern matching for service worker scope
• Prototype HTTP Supports-Loading-Mode response header (prerendering opt-in)
• Prototype and ship CSS :dir() pseudo-class
• Experiment Local Font Access
• Ship CSS hyphens: auto value on Windows
• Ship CSS :is() and :where() pseudo-classes
• Prototype CSS scrollbar-color and scrollbar-width properties
• Prototype TLS Encrypted Client Hello (ECH)
• Ship CSS clip-path: path() values
• Prototype CSS prefers-contrast media feature
• Prototype CSS ::target-text pseudo-element
• Prototype getCurrentBrowsingContextMedia method
• Prototype WebID
• Ship CSS aspect-ratio property
• Prototype Storage Buckets API
• Experiment WebXR Depth API
• Experiment Declarative Shadow DOM (cont.)
• Ship “Partition the HTTP cache”

September 2020

• Ship HTTP Permissions-Policy header
• Experiment scheduler.postTask method for main-thread scheduling (cont.)
• Ship Cross-Origin Isolation
• Prototype platform-issued trust tokens
• Experiment QuicTransport (cont.)
• Ship CSS text-decoration-thickness and text-underline-offset properties, and text-underline-position: from-font value
• Experiment Idle Detection API (cont.)
• Experiment Notification Triggers (cont.)
• Experiment Origin Isolation (cont.)
• Experiment performance.measureMemory method (cont.)
• Ship navigator.scheduling.isInputPending method
• Ship CSS ascent-override, descent-override, and line-gap-override font descriptors
• Ship Cookie Store API
• Experiment Conversion Measurement API
• Ship Web Share API on Windows and Chrome OS
• Prototype HTTP Critical-CH response header
• Prototype and ship Screen Wake Lock released property

August 2020

• Experiment Digital Goods API
• Experiment WebCodecs
• Prototype CSS overflow: clip value and overflow-clip-margin property
• Ship CSS flow-relative box model properties
• Prototype customizable <select> element
• Prototype Progressive Web Apps as URL Handlers
• Ship Native File System API
• Prototype Raw Sockets API
• Prototype HTTP Permissions-Policy header
• Ship CSS quotes: auto value
• Ship Transferable Streams
• Experiment Multi-Screen Window Placement
• Prototype WebXR Depth API
• Prototype First-Party Sets
• Experiment beforematch event and CSS content-visibility: hidden-matchable value
• Experiment HTML <meta name="battery-savings"> tag
• Ship Imperative Shadow DOM Distribution API
• Experiment Serial API (cont.)
• Ship opt-out for Scroll To Text Fragment (force-load-at-top document policy)
• Prototype SVG image support for the Async Clipboard API
• Prototype HTML <meta name="battery-savings"> tag
• Prototype re-enabled SharedArrayBuffer gated behind COOP/COEP (on Android)

July 2020

• Prototype HTTP Content-Encoding: jxl value (JPEG XL)
• Ship strict-origin-when-cross-origin as default referrer policy
• Implement Web Share API on Windows and Chrome OS
• Ship HTTP Document-Policy header
• Ship altitude and azimuth angles for Pointer Events
• Prototype @font-face descriptors for overriding font metrics (e.g., ascent-override)
• Experiment opt-out for Scroll To Text Fragment
• Implement and ship WebXR AR Module
• Ship Permission Policty web-share permission
• Experiment Declarative Shadow DOM
• Implement and ship DOM replaceChildren method
• Ship CSS ::marker pseudo-element
• Prototype 'visibility-state' performance entries
• Prototype and ship FetchEvent handled property (promise)
• Prototype WebAuthn Level 2 and CTAP2.1
• Prototype quotachange event (storage pressure)
• Prototype Sanitizer API

June 2020

• Ship Web Bluetooth getDevices and watchAdvertisements methods
• Ship AVIF (image format)
• Prototype and ship Feature Policy clipboard-read and clipboard-write policies
• Ship Media Feeds (<link rel="media-feed">)
• Implement and ship HTMLMediaElement preservesPitch property
• Implement and ship PictureInPictureEvent pictureInPictureWindow property
• Prototype Cross-Origin Isolation
• Prototype CSS scrollbar-gutter property
• Prototype CSS color-mix() function
• Implement and ship CSS counter-set property
• Experiment WebHID (Human Interface Device)
• Ship WebXR Anchors
• Prototype Web Manifest "display-override" field
• Implement and ship Intensive JavaScript Timer Throttling
• Ship CSS content-visibility property
• Prototype WebXR Raw Camera Access

May 2020

• Prototype CSS attr() function Level 4 extension
• Implement and ship updated CSS color-scheme property
• Prototype MediaBlob (improved client side video editing)
• Prototype subresource loading with Web Bundles
• Experiment performance.measureMemory method (cont.)
• Prototype MulticastReceiver API
• Ship Event Timing
• Implement and ship CSS attr() function Level 4 extension
• Experiment QuicTransport
• Ship App Icon Shortcuts Menu
• Experiment Cookie Store API
• Ship CSS row-gap and column-gap properties in Flexbox Layout
• Experiment Origin Isolation
• Experiment Trust Token API
• Prototype beforematch event

April 2020

• Ship Forced Colors Mode (CSS forced-color-adjust property)
• Experiment Idle Detection API
• Prototype Web Bluetooth watchAdvertisements method
• Ship Web Animations API
• Ship CSS @property at-rule
• Experiment HTML rendersubtree attribute (cont.)
• Ship Content Index API
• Prototype Virtual Keyboard API
• Prototype Window Segments Enumeration API
• Experiment Portals (same-origin, Android only)
• Prototype altitude and azimuth angles for Pointer Events
• Prototype App Icon Shortcuts Menu
• Ship navigator.getInstalledRelatedApps API on Windows
• Prototype Window Controls Overlay for Installed Desktop Web Apps
• Prototype CSS text-decoration-thickness and text-underline-offset properties, and text-underline-position: from-font value

March 2020

• Ship CSS revert keyword
• Ship Web OTP API (requesting one-time-passwords)
• Prototype CSS lch() and lab() functions (CIE LAB color functions)
• Prototype CSS page property (named pages) and page-orientation descriptor
• Prototype CSS aspect-ratio property
• Experiment Native File System API (cont.)
• Prototype Font Access API (enumerate installed fonts and obtain table data)
• Ship Wake Lock API
• Implement and ship (unprefixed) CSS appearance property
• Implement and ship CSS -webkit-appearance: auto value
• Ship WebXR DOM Overlay
• Ship off and noscroll values for the <iframe scrolling> attribute
• Experiment performance.measureMemory method

February 2020

• Ship Cross-Origin Opener Policy (COOP)
• Prototype Imperative Shadow DOM Distribution API
• Ship Cross-Origin Embedder Policy (COEP)
• Prototype URL Protocol Handler Registration for PWAs
• Prototype Web Bluetooth getDevices method
• Ship CSS :state() pseudo-class
• Prototype Media Feeds API
• Ship durability property for IndexedDB transactions (durability hint)
• Ship <iframe disallowdocumentaccess> attribute
• Ship ARIA suggestion, mark, and comment roles and aria-description attribute (ARIA annotations)
• Ship CSS contain-intrinsic-size property
• Prototype CSS prefers-reduced-data media feature
• Prototype Declarative Shadow DOM
• Prototype CSS spanning media feature and fold-top/fold-left/fold-width/fold-height environment variables
• Implement and ship CSS font-display: optional without relayout
• Prototype rawValue property for <input> elements
• Experiment scheduler.postTask method for main-thread scheduling

January 2020

• Implement and ship <input type="time"> with a reversed range (min > max)
• Ship requestAnimationFrame method for <video> elements
• Prototype CSS row-gap and column-gap properties in Flexbox Layout
• Ship WebXR Hit Testing
• Prototype mechanism for running PWAs on startup
• Implement and ship WebXR Augmented Reality (AR) Module
• Prototype Origin Isolation
• Prototype Origin Policy
• Ship CSS color-scheme property and "color-scheme" <meta> value
• Ship HTTP Sec-CH-UA-* headers (Client Hints)
• Deprecate and freeze HTTP User-Agent header value
• Experiment Web NFC
• Ship Badging API
• Prototype timezonechange event
• Experiment Native File System API (cont.)

December 2019

• Prototype Service Worker Scope Pattern Matching
• Ship Periodic Background Sync
• Implement and ship buffered option for Performance Observer
• Implement and ship submitter property for submit events
• Ship Compression Streams

November 2019

• Prototype and ship Resize Observer contentBoxSize, borderBoxSize, and devicePixelContentBoxSize properties
• Ship HTML <a hreftranslate> attribute
• Ship HTTP Sec-Fetch-Dest request header
• Ship Media Playback Quality (getVideoPlaybackQuality method)
• Ship CSS ActiveText, Field, and FieldText values (system color keywords)
• Implement and ship CSS image-orientation property
• Experiment Content Index API
• Implement spatialNavigationSearch method (part of CSS Spatial Navigation)
• Experiment Contact Picker API (cont.)
• Ship navigator.getInstalledRelatedApps API
• Ship CSS :focus-visible pseudo-class
• Implement Window Placement
• Ship CSS intrinsic-size property

October 2019

• Ship default semantics for custom elements via the ElementInternals object
• Ship ARIA attribute reflection
• Implement latencyHint attribute for HTML media elements
• Experiment ARIA annotation-attribution, annotation-commentary, annotation-presence, annotation-revision, annotation-suggestion roles
• Implement WebCodecs (access to built-in media encoders/decoders)
• Ship CSS Canvas and Text system color keywords
• Implement strict-origin-when-cross-origin as new default for Referrer Policy
• Implement Conversion Measurement API
• Implement MathML Core
• Experiment Serial API
• Implement Trust Token API
• Implement CSS :state() pseudo-class
• Ship Scroll To Text Fragment
• Implement Raw Clipboard Access
• Experiment HTML rendersubtree attribute and CSS content-size property
• Ship Trusted Types
• Implement requestAnimationFrame method for <video> elements
• Implement and ship CSS @supports selector() function
• Ship image/video aspect ratios from HTML width and height attributes
• Implement QuicTransport API (part of the WebTransport framework)
• Ship WebXR Device API
• Ship WebXR Gamepads Module
• Implement and ship string values for the CSS list-style-type property
• Ship CSS line-break: anywhere value
• Implement and ship CSS overflow-wrap: anywhere value

September 2019

• Implement percent-based scrolling
• Implement “heavy ad” intervention
• Implement ARIA roles for annotation purposes
• Implement and ship CSS font-optical-sizing property
• Implement HTML rendersubtree attribute
• Implement Screen Enumeration (navigator.screen.requestDisplays method)
• Ship auto-upgrade mixed audio and video content (http: to https:)
• Implement navigation to Bundled HTTP Exchanges (Web Packaging)
• Implement CSS navigation-controls media feature
• Experiment Wake Lock API
• Experiment SMS Receiver API
• Implement EditContext API
• Implement image/video aspect ratios from HTML width and height attributes
• Experiment Notification Triggers (show notifications when certain conditions are met)
• Implement and ship autofocus attribute on any focusable HTML/SVG element
• Experiment Native File System API
• Implement relaxedDurability option for the IndexedDB transaction method (controls flushing to disk)

August 2019

• Implement navigator.scheduling.isFramePending method
• Implement CompressStream and DecompressStream APIs
• Experiment WebXR Device API (cont.)
• Implement CSS content-size property
• Implement and ship inline styles in WebVTT files
• Implement Font Enumeration API
• Experiment Badging API V2 (different badges depending on URL scope)
• Experiment JS Self-Profiling API
• Implement Element Reflection (“allow specifying semantic relationships between elements without the need to assign globally unique ID attributes”)
• Implement API for accessing TrueType/OpenType font tables
• Implement Document Policy
• Deprecate and remove non-Secure cookies in third-party contexts
• Implement and ship WebAuthn in cross-origin iframes
• Implement CSS Modules V1
• Implement WebXR Anchors
• Implement default accessibility semantics for custom elements
• Experiment Periodic Background Sync
• Deprecate and remove Shadow DOM v0, Custom Elements v0, and HTML Imports (cont.)s

July 2019

• Implement scheduler.postTask method for main-thread scheduling
• Implement Feature Policy document-access policy
• Experiment navigator.scheduling.isInputPending method (early detection of input events)
• Implement Storage Access API
• Ship Barcode Detection API (part of Shape Detection API)
• Ship Layout Instability API
• Implement JSON Modules
• Implement and ship buffered option for PerformanceObserver observe method
• Experiment Trusted Types (cont.)
• Experiment navigator.getInstalledRelatedApps API (cont.)
• Ship Element Timing
• Ship Largest Contentful Paint (LCP) page-load metric

June 2019

• Implement and ship CSS overscroll-behavior-inline and overscroll-behavior-block properties
• Experiment Scroll To Text Fragment
• Ship alternative text for the CSS content property
• Implement and ship CSS min(), max() and clamp() functions
• Ship Animation Worklet
• Experiment Feature Policy Reporting (cont.)
• Implement and ship integrity attribute on <link rel="preload"> elements
• Implement and ship CSS font-size: xxx-large value
• Implement <std-toast> element (toast notification)
• Implement Content Indexing
• Implement CSS @property at-rule
• Implement JavaScript Memory API (performance.measureMemory method)
• Implement <std-switch> element (toggle switch control)
• Implement and ship Web Bluetooth getAvailability method

May 2019

• Implement jump-start, jump-end, jump-none, and jump-both keywords for the CSS steps() easing function
• Implement HTTP Cross-Origin-Opener-Policy response header
• Implement Largest Contentful Paint (LCP) metric
• Implement and ship changes to cookies (add SameSite=Lax by default)
• Ship Feature Policy focus-without-user-activation policy
• Experiment lowLatency option for '2d' and 'webgl' canvas contexts (cont.)
• Implement CSS color-scheme property
• Implement and ship enterkeyhint attribute
• Ship ImageBitmap rendering context for OffscreenCanvas
• Ship form-associated custom elements
• Ship 'formdata' event type
• Implement and ship HTMLFormElement requestSubmit method
• Experiment WebXR Device API (cont.)
• Implement and ship CSS scroll-snap-stop property
• Implement Bundled HTTP Exchanges
• Ship pointerrawmove event type
• Experiment Badging API (cont.)
• Implement and ship Animation pending property
• Ship CSS prefers-color-scheme media feature

April 2019

• Ship IDBTransaction commit method
• Implement Feature Policy execution-while-out-of-viewport and execution-while-not-rendered features (enables freezing hidden iframes)
• Implement Periodic Background Sync
• Implement JS Self-Profiling API
• Implement Picture-in-Picture for arbitrary content
• Experiment <a hrefTranslate> attribute (cont.)
• Experiment Event Timing API (cont.)
• Ship CSS white-space: break-spaces value
• Experiment HTML importance attribute (Priority Hints) (cont.)
• Ship Storage Quota Usage Details
• Implement SMS OTP Retriever API
• Ship image support for the Async Clipboard API
• Implement and ship Blob text, arrayBuffer, and stream methods
• Implement Gamepad light indicator extension
• Ship HTTP Sec-Fetch-Mode, Sec-Fetch-Site, and Sec-Fetch-User request headers
• Ship arbitrary timestamps and metadata in User Timing
• Ship Animation constructor (Web Animations)

March 2019

• Ship Web Share Target Level 2 (adds support for files)
• Implement Native Caret Browsing
• Implement and ship CSS :picture-in-picture pseudo-class
• Implement and ship SVG favicons (<link rel="icon">)
• Ship desynchronized option for 2D canvas context (was lowLatency)
• Implement Element Timing for text
• Ship Feature Policy document-domain feature
• Implement and ship HTML <video playsinline> attribute
• Implement CSS outline-color: invert value
• Implement and ship CSS backdrop-filter property
• Implement alternative text for the CSS content property
• Experiment KV Storage + import maps
• Ship Background Fetch
• Implement CSS line-break: anywhere value

February 2019

• Implement image support for the Async Clipboard API
• Implement and experiment Feature Policy unoptimized-images and oversized-images features
• Ship Signed Exchange Reporting for distributors
• Ship PointerEvent getPredictedEvents method
• Implement Notification Triggers (show notifications when certain conditions are met)
• Implement import maps (<script type="importmap">)
• Implement Signed Exchange Reporting for distributors
• Experiment Event Timing API (cont.)

January 2019

• Implement and ship CSS transition events (transitionrun, transitionstart, and transitioncancel)
• Experiment HTML <video autoPictureInPicture> attribute
• Implement HTML <meta name="supported-color-schemes"> element
• Ship Intersection Observer V2
• Implement and ship HTTP Cross-Origin-Resource-Policy header
• Implement HTTP Sec-CH-UA-* headers (Client Hints)
• Experiment HTML importance attribute (Priority Hints)
• Experiment Web Contact API
• Implement HTTP Sec-CH-Lang header (Client Hints)
• Experiment navigator.getInstalledRelatedApps API
• Implement and ship CSS font-optical-sizing property
• Ship Signed HTTP Exchanges (SXG)
• Implement file sharing in Web Share API
• Implement HTML Modules
• Experiment <img elementtiming> attribute
• Experiment Feature Policy Reporting
• Experiment 'layoutjank' performance entries
• Experiment Event Timing API (cont.)
• Experiment Trusted Types for DOM Manipulation
• Ship imagesrcset and imagesizes attributes for the <link> element (selectively preloading images)
• Implement and ship CSS prefers-reduced-motion media feature
• Implement CSS prefers-color-scheme media feature

December 2018

• Implement and ship document.featurePolicy API (for policy introspection)
• Implement Web Bluetooth Scanning
• Implement scroll-linked animations (only JavaScript part)
• Ship stale-while-revalidate Cache-control extension
• Ship CSS ::part pseudo-element (CSS Shadow Parts)
• Ship Constructable Stylesheet Objects
• Experiment Signed HTTP Exchanges (cont.)
• Experiment lowLatency option for '2d' and 'webgl' canvas contexts (cont.)
• Ship GamepadButton touched property
• Experiment Badging API
• Implement and ship PerformanceObserver.supportedEntryTypes property

November 2018

• Experiment Web XR Device API (cont.)
• Ship First Input Timing
• Implement Storage Quota Usage Details
• Experiment <a hrefTranslate> attribute
• Implement User Idle Detection
• Implement form-associated custom elements
• Implement Contacts API
• Implement Feature Policy document-domain feature
• Ship Intl.ListFormat API
• Ship crash reports (Reporting API)
• Ship keyboard-focusable scroll containers
• Ship an API for enumerating IndexedDB databases
• Ship CSS Properties and Values API Level 1 (subset)

October 2018

• Implement FetchEvent Worker Timing (measuring the performance of service workers)
• Implement an explicit API for commiting IndexedDB transactions
• Ship colorSpace and pixelFormat options for canvas contexts (canvas color management)
• Implement CSS font-display descriptor for @font-feature-values (setting the default font-display value for a font family)
• Experiment lowLatency option for '2d' and 'webgl' canvas contexts
• Experiment Event Timing API (cont.)
• Implement 'layoutjank' performance entry (Performance API)
• Ship navigator.getDisplayMedia method (Screen Capture)
• Ship spec-compliant specificity for CSS Scoping selectors (:host(), etc.)
• Experiment Background Fetch

September 2018

• Implement WebHID
• Experiment Signed HTTP Exchanges
• Implement Gamepad API touchpad extension
• Implement crash reports (Reporting API)
• Implement PointerEvent getPredictedEvents method
• Implement IndexedDB database enumeration API
• Implement Serial API
• Implement navigator.isProtocolHandlerRegistered method
• Ship CSP report-to directive
• Implement Display Locking
• Implement Element Timing for images (incl. <img elementtiming> attribute)
• Ship User Activation API
• Ship TextEncoderStream and TextDecoderStream APIs
• Implement and ship CSP script-src-attr, script-src-elem, style-src-attr, and style-src-elem directives
• Implement and ship queueMicrotask function
• Experiment WebXR Device API (cont.)

August 2018

• Ship prefersNavigationBar option for Fullscreen API
• Ship Permission Delegation
• Implement pointerrawmove event type
• Implement an API to measure the memory footprint of the website
• Implement HTML intrinsicsize attribute (for images and videos)
• Remove Budget API
• Implement Feature Policy animations feature
• Implement Feature Policy violation reports ('feature-policy-violation' report type)
• Implement searchable invisible DOM
• Implement and ship TLS 1.3
• Implement HTML <a hreftranslate> attribute
• Implement Writable Files
• Implement Feature Policy lazyload feature
• Implement Shadow DOM imperative distributed API
• Ship WebSockets over HTTP/2
• Deprecate and remove Shadow DOM v0, Custom Elements v0, and HTML Imports

July 2018

• Implement iframe sandboxing features as Feature Policy features
• Implement Badging API
• Implement HTML <portal> element for seamless navigations between sites or pages
• Experiment Feature Policy API (document.policy)
• Implement and ship queueMicrotask function
• Implement options argument for the postMessage method
• Experiment Web Locks API (cont.)
• Implement Feature Policy sync-script feature (for disabling parser-blocking script execution)
• Ship intervention reports
• Experiment stale-while-revalidate directive for HTTP Cache-Control header
• Implement and ship left and right values for the CSS text-underline-position property

June 2018

• Implement gamepadbuttondown, gamepadbuttonup, gamepadbuttonchange, and gamepadaxismove events
• Ship Web Locks API
• Implement and ship DOM Element toggleAttribute method
• Experiment Cookie Store API
• Ship Notification Inline Replies
• Implement stale-while-revalidate directive for HTTP Cache-Control header
• Ship CSS environment variables and viewport-fit descriptor for <meta name="viewport">
• Implement CSP 'unsafe-hashes' source expression
• Ship Keyboard Map (navigator.keyboard and keyboardchange event)
• Implement and ship module workers (type: 'module' option for Worker constructor)
• Implement navigator.getDisplayMedia method (Screen Capture)
• Ship Picture-in-Picture (requestPictureInPicture method)
• Experiment Event Timing API
• Ship Request isHistoryNavigation property
• Implement an API for querying the user activation state
• Ship deprecation reports and the ReportingObserver API
• Implement and ship nested, dedicated workers

May 2018

• Implement WebGPU API
• Implement and ship CSS Logical Properties
• Implement HTTP Sec-Metadata request header
• Ship Web Lifecycle
• Implement TextEncoderStream and TextDecoderStream APIs
• Implement scroll target based on CSS selector in URL fragment
• Ship Reporting API and Network Error Logging
• Implement Gamepad API touchpad extension
• Ship <script referrerpolicy> attribute
• Ship CSS Scroll Snap
• Experiment Picture-in-Picture (requestPictureInPicture method)
• Ship Keyboard Lock API (second intent)
• Implement element visibility reporting for Intersection Observer API (trackVisibility and isVisible properties)
• Implement Async Local Storage API (layered API)
• Implement HTML <virtual-list> element (layered API)
• Implement and ship AnimationEvent pseudoElement property (CSS Animations)

April 2018

• Implement infrastructure for Layered APIs
• Ship 'same-origin' as the default credentials mode for fetch() (the previous default was 'omit')
• Ship HTTP Network-RTT and Network-BW request headers (network quality estimates)
• Implement Priority Hints API (importance attribute)
• Implement and ship CSS overflow shorthand (accepts two values)
• Implement User Timing Level 3 extensions
• Implement Wake Lock API
• Implement prefersNavigationBar option for Fullscreen API
• Implement and ship Cross-Origin Read Blocking (CORB)
• Implement Keyboard Map (navigator.keyboard and keyboardchange event)
• Implement Event Timing API ('event' performance entries)
• Implement customElements.upgrade method

March 2018

• Ship events for back/forward mouse buttons (button property values 3 and 4)
• Implement style option for customElements.define method (for providing a custom element’s default styles)
• Implement formdata event type (Form Participation API)
• Ship unified touch adjustment
• Ship Motion Sensors (based on Generic Sensor API)
• Ship Web Authentication API (with FIDO U2F support)
• Ship TransformStream constructor
• Ship CSS conic-gradient() function
• Ship customized built-in elements
• Implement and ship CSP navigate-to directive
• Ship HTTP Accept-CH-Lifetime response header
• Implement CSS Shadow Parts (::part() and ::theme() pseudo-elements)
• Experiment AudioWorklet

February 2018

• Implement CSS :focus-visible pseudo-class
• Ship Media Capabilities API (getting information about decoding capabilities)
• Ship <slot> elements in the flat tree
• Implement WebSockets over HTTP/2
• Implement srcset and imgsizes attributes on <link rel="preload" as="image"> elements
• Ship modulepreload link relation
• Experiment CSS Animation Worklet API
• Ship AudioWorklet
• Ship HTML inputmode attribute
• Experiment Web Locks API
• Implement and ship: Expand list of properties that can apply to CSS ::first-letter pseudo-elements
• Ship Payment Handler API
• Implement constructable style sheet objects (CSSStyleSheet constructor)
• Implement CSS :is() pseudo-class

January 2018

• Implement and ship CSS x unit (synonym for dppx)
• Implement “Lazily load below-the-fold iframes and images”
• Ship CSS justify-items: legacy value
• Implement CSS justify-items: legacy value
• Experiment “Extend Subresource Integrity (<script integrity>) to support validating a resource’s signature”
• Implement Picture-in-Picture (video.requestPictureInPicture())
• Deprecate and remove # in data URL body (the first # will be treated as the start of the fragment)
• Implement and ship CSS row-gap, column-gap, and gap properties (grid-row-gap/etc. become aliases)
• Implement and ship CSS calc() in media queries
• Ship CSS Typed OM
• Implement and ship “Fire an input event when a range or file <input> element is activated”
• Implement and ship Performance Observer takeRecords method
• Implement Permission Delegation (through <iframe allow> attribute)
• Implement and ship Feature Policy sync-xhr feature
• Experiment Media Capabilities API (cont.)
• Implement and ship “Fire an input event when a (mutable) checkbox is clicked”
• Implement (a subset of the) CSS Layout API
• Ship Async Clipboard API
• Implement and ship HTMLAnchorElement relList property
• Experiment WebVR 1.1
• Ship Fetch API keepalive option

December 2017

• Ship CSS display: contents value
• Implement CSS :matches() pseudo-class
• Implement and ship Feature Policy accelerometer, gyroscope, magnetometer features
• Implement and ship Abortable fetch (AbortController and AbortSignal)
• Implement unified touch adjustment
• Ship Feature Policy autoplay feature
• Ship CSS :any-link pseudo-class
• Ship TLS 1.3 draft-22 in 1-RTT mode
• Ship <img decoding> attribute
• Ship Network Information saveData property

November 2017

• Implement CSS :any-link pseudo-class
• Implement and ship HTTP 425 (Too Early) status code
• Implement Feature Policy autoplay feature
• Implement and ship delayed dispatch of performance entries
• Implement and ship WebVTT positionAlign and lineAlign properties
• Implement events for back/forward mouse buttons (button property values 3 and 4)
• Experiment Web Audio API AudioWorklet interface
• Implement Web Locks API
• Implement and ship autocapitalize attribute on <form> and contenteditable elements
• Ship Fetch API cache option (also a property on Request objects)
• Experiment CSS line-height-step property
• Implement modulepreload link relation
• Implement and ship (subclassable) EventTarget constructor
• Implement transform streams
• Implement and ship preventScroll option for focus APIs

October 2017

• Ship HTML <iframe delegatestickyuseractivation> attibute
• Ship CSS transform-box property
• Ship CSS text-decoration-skip-ink property (and remove text-decoration-skip: ink value)
• Implement stylable <slot> elements (assigned nodes inherit style)
• Implement Fetch API keepalive option
• Implement Web Lifecycle
• Implement Network Information saveData property
• Implement <img async> attribute
• Implement and ship CSP 'unsafe-hashed-attributes' source expression

September 2017

• Ship Resize Observer API
• Implement and ship <textarea autocomplete> and <select autocomplete> attributes
• Implement CSS overflow-wrap: break-spaces value
• Ship JavaScript import() syntax for dynamic imports
• Implement Gesture Delegation (HTMLIframeElement allowedActivationDelegation property)
• Implement trusted types for DOM manipulation
• Implement PauseFrame API
• Ship “Send mouse events (excluding click) to disabled form controls”
• Implement and ship MediaStreamTrack applyConstraints method
• Experiment Media Capabilities API
• Ship CSS Paint API
• Implement CSS Animation Worklet API
• Ship Intl NumberFormat formatToParts method
• Implement revised WebVR API
• Ship Promise finally method
• Ship CSS scroll-boundary-behavior property
• Ship Keyboard Lock API (navigator.requestKeyboardLock method)
• Implement options argument for Element focus method

August 2017

• Ship navigator.deviceMemory property
• Implement and ship history.index property
• Implement and ship “Treat http://localhost as a secure context”
• Implement and ship CSS q unit
• Implement Gamepad API haptics extension
• Ship Server Timing
• Ship Performance timeOrigin property
• Experiment Generic Sensor API
• Experiment WebVR (cont.)
• Ship “Dispatch mouse transition events after layout”
• Ship collapsable table rows (via CSS visibility: collapse)
• Implement Origin Policy

July 2017

• Ship s flag for JavaScript regular expressions
• Implement performance.timeOrigin property
• Ship HTMLImageElement decode method
• Ship HTTP Device-Memory header
• Ship HTTP Expect-CT header
• Implement JavaScript import() syntax for dynamic imports

June 2017

• Experiment Shape Detection API
• Ship OpenType variable fonts
• Implement and ship beforeprint and afterprint events
• Implement and ship HTML <time> element
• Implement and ship HTML <data> element
• Implement and ship URLSearchParams sort method
• Implement collapsable table rows (via CSS visibility: collapse)
• Ship <script type="module">
• Ship inert visual viewport and Visual Viewport API
• Ship HTTP Clear-Site-Data header
• Ship ImageCapture getPhotoSettings method
• Ship Web Share API
• Implement deprecation reports and the ReportingObserver API
• Implement and ship “Move the role of the scrolling element from <body> to <html>”
• Implement and ship Referrer Policy 'same-origin', 'strict-origin', and 'strict-origin-when-cross-origin' values

May 2017

• Implement and ship “Exit fullscreen mode if a JavaScript dialog is shown”
• Implement and ship Element getAttributeNames method
• Ship WebUSB
• Ship CSP Embedded Enforcement (<iframe csp> attribute)
• Implement and ship DOMTokenList replace method
• Implement and ship mandatory as value for preload links
• Implement and ship navigator.webdriver property
• Implement CSP report-to directive
• Ship Network Information API downlink, rtt, and effectiveType properties
• Ship Storage API navigator.storage.estimate method
• Implement and ship CSS Box Alignment for Flexbox Layout
• Ship stricter X-Frame-Options: SAMEORIGIN (check all ancestor frames)
• Ship First Paint Timing API (PerformancePaintTiming interface)
• Implement and ship Credential Management API password property
• Implement and ship messageerror event
• Ship Fetch API formData method

April 2017

• Implement HTTP Device-Ram header and navigator.deviceRam API
• Ship Web Payment Manifest
• Ship Navigation Preload for Service Worker
• Implement Memory Pressure API
• Implement and ship CSS scroll-behavior property and behavior option for scroll APIs (enables smooth scrolling)
• Ship Budget API reserve method
• Experiment Budget API getCost and getBudget methods

March 2017

• Implement HTMLImageElement decode method
• Ship ReadableStream pipeTo and pipeThrough methods
• Ship writable streams
• Ship APNG
• Implement CSS transform-box property
• Implement and ship “CSP hash expressions matching external scripts” (<script integrity>)
• Implement and ship DataTransfer constructor
• Experiment navigator.getInstalledRelatedApps API
• Ship InputEvent
• Ship Image Capture
• Implement Web Payment Manifest
• Implement and ship CSS frames() timing function
• Implement and ship CSS :focus-within pseudo-class
• Ship Feature Policy v1
• Ship script-sample property in CSP violation reports
• Implement CSS conic-gradient() notation
• Implement Accessibility Object Model
• Implement Server Timing
• Implement and ship HDR display detection via screen.colorDepth, screen.pixelDepth, and the CSS color media feature
• Ship Geometry Interfaces
• Ship “Android on-screen keyboard doesn’t resize layout”
• Implement sample property for CSP reports

February 2017

• Ship animations/transitions on the CSS offset-path property
• Implement and ship “Temporarily stop permission requests after 3 dismissals”
• Implement and ship HTMLMediaElement controlsList property (for customizing native media controls)
• Implement and ship CSS Box Alignment place-* (shorthand) properties
• Ship allow-top-navigation-by-user-activation keyword for <iframe sandbox>
• Ship IndexedDB 2.0 APIs
• Implement HTML inert attribute
• Implement Media Capabilities API (getting information about decoding capabilities)
• Implement and ship “Pause <video muted autoplay> when invisible (on Android)
• Implement and ship global origin property (self.origin)
• Implement and ship construcing workers with data: URLs
• Implement HTTP Network-RTT and Network-BW headers (Network Information API extension)
• Ship Long Task API

January 2017

• Implement and ship CSS color-gamut media feature
• Implement Background Fetch API
• Implement uncancellable touch events when the main thread is busy (intervention)
• Remove prerendering in Chrome
• Ship CSS font-display property
• Implement and ship “Send all keys (except ESC/F11) to the web app when the browser is in fullscreen mode”
• Ship PointerEvent getCoalescedEvents method
• Ship CSS line-height-step property
• Ship Token Binding
• Experiment “navigation preload for service workers”
• Implement CSS Logical Properties (margin-* properties)
• Experiment WebUSB (another Origin Trial)
• Implement and ship PointerEvent tangentialPressure and twist properties
• Ship WebAssembly
• Implement and ship CSS display: flow-root value
• Ship Media Session API
• Implement Expect-CT header
• Experiment document.rootScroller property
• Implement Canvas color management (colorSpace property)

December 2016

• Implement and ship rel="prefetch" in Link header
• Implement asynchronous Clipboard API
• Implement and ship ARIA 1.1
• Implement Reporting API
• Ship ClipboardEvent constructor
• Implement and ship CSS Logical Properties (*-size properties)
• Implement System Keyboard Lock
• Implement CSS scroll-boundary-behavior property
• Implement and ship Web App Manifest purpose field (for icons)
• Implement Web Share Target API
• Implement and ship SVG transform presentation attributes
• Implement MediaStreamTrack Content Hints
• Implement and ship Presentation API 1-UA mode
• Implement Phone number API (a.k.a. Sign up API)

November 2016

• Implement ReadableStream pipeTo and pipeThrough methods
• Implement PerformancePaintTiming interface (incl. time to first paint)
• Implement and ship changes to CSP’s model for workers
• Implement OpenType variable fonts
• Implement and ship <iframe allowpaymentrequest> attribute
• Implement PointerEvent getCoalescedEvents method
• Ship CSS text-decoration-* properties
• Implement and ship CSS ::placeholder pseudo-element
• Ship Remote Playback API
• Implement and ship CSS caret-color property
• Ship CSS Grid Layout
• Implement Web Authentication API
• Implement and ship Payment Request API canMakeActivePayment method
• Ship “Fire visibilitychange event on document unloading”
• Implement and ship Navigation Timing Level 2
• Implement and ship Resource Timing nextHopProtocol property
• Implement and ship CSP's worker-src directive
• Implement Payment App API
• Implement navigation preload for service workers
• Ship scroll anchoring

October 2016

• Implement and ship <link referrerpolicy> attribute
• Ship CSS position: sticky value
• Implement FIDO U2F API
• Implement and ship Fractional MouseEvent coordinates
• Implement and ship KeyboardEvent isComposing property
• Implement WritableStream (part of Streams API)
• Implement CSS shape media feature
• Ship WebGL 2.0
• Ship TLS 1.3 1-RTT (field trial)
• Implement and ship ImageBitmap rendering context for <canvas>
• Remove CSP 'referrer' directive
• Implement and ship CSS display: contents value
• Intervene “Treat touch Scroll-blocking event listeners as passive”
• Implement and ship PresentationConnection.url property
• Ship Web Bluetooth
• Ship “Render Unicode control characters”
• Implement and ship CSS system-ui generic font family
• Ship Notification API image property (“a large image as part of the content of a notification”)
• Ship durable (persistent) storage
• Implement customized built-in elements
• Ship HTTP Referrer-Policy header

September 2016

• Ship CSP violation event disposition property
• Experiment Long Task API
• Implement CSS overscroll-action property
• Ship pinch-zoom value for CSS touch-action property
• Implement Content Security Policy: Embedded Enforcement
• Experiment MediaStream Image Capture
• Ship MediaStream constructor
• Implement and ship CSS text-decoration-skip property (and default to ink value)
• Ship Pointer Events
• Ship ECMAScript async functions
• Implement and ship constructible document with new Document()
• Experiment WebVR
• Ship MediaDevices devicechange event
• Ship CSS hyphens property
• Implement “Process continuous events just before requestAnimationFrame occurs”
• Implement Shape Detection API
• Implement AudioWorklets for Web Audio API

August 2016

• Implement Accelerometer, Gyroscope and Magnetometer Sensor APIs
• Implement CSS Properties and Values API
• Experiment Web Share API on Android
• Ship auxclick event type
• Implement IndexedDB object store and index renaming (during version change transactions)
• Implement Notifications API image property
• Experiment WebUSB (updated)
• Ship custom elements v1
• Implement once option for addEventListener method
• Ship media tracks (limited to 1 audio/video track)
• Implement and ship dataset API on SVG elements
• Experiment foreign fetch and serviceworker link relation
• Implement and ship unprefixed CSS -webkit-image-set function
• Implement “long task” notifications in Performance Observer
• Ship visual viewport
• Implement Budget API

July 2016

• Ship ParentNode/ChildNode prepend/append/before/after/replaceWith methods
• Ship pan-up/pan-down/pan-left/pan-right values for CSS touch-action property (follow up)
• Implement and ship “Allow web pages to request fullscreen while an orientation change event handler is running”
• Implement and ship Node.getRootNode method (was Node.rootNode)
• Implement Content Size Policy
• Implement and ship Gamepad API extensions (touched and pose properties)
• Ship BroadcastChannel API
• Implement CSP require-sri-for directive
• Implement and ship Push API PushSubscription.options property
• Implement "auxclick" event type (non-primary button click)
• Implement and ship “Block navigator.vibrate in cross-origin iframes”
• Ship pan-up/pan-down/pan-left/pan-right values for CSS touch-action property

June 2016

• Ship PaymentRequest API
• Implement and ship "install" event for Web App Manifest
• Implement and ship timer throttling for hidden, cross-origin frames
• Implement Feature Policy
• Implement and ship CSS the text-size-adjust property
• Ship Shadow DOM v1
• Ship Media Capture from <audio>/<video> (“WebRTC streaming of prerecorded content”)
• Implement Web Share API
• Implement Referrer-Policy HTTP header
• Ship “Do not perform default action on un-trusted events”
• Implement “Web Audio requires user gesture on Android”
• Implement and ship “Autoplay muted videos on Android” (<video autoplay muted>)
• Implement and ship Resource Timing transferSize/encodedBodySize/decodedBodySize properties
• Implement “Block cross-origin scripts inserted via document.write” (for users on slow connections)
• Implement Media Capture Depth Stream Extensions (media stream from depth camera)

May 2016

• Ship HTTP Alternative Services
• Implement and ship “External stylesheets in <body> do not block paint”
• Implement and ship CSS nav-up, nav-down, nav-left, nav-right properties
• Implement and ship “Apply u flag to <input pattern> attribute”
• Implement and ship allow-presentation token for <iframe sandbox> attribute
• Implement Resize Observer API
• Ship “Specifying a ReadableStream response body in the Response constructor”
• Implement permission delegation for <iframe>s
• Ship (read-only) action/vibrate attributes on Notification instances
• Ship “Do not perform default action on untrusted events”
• Implement ECMAScript async functions (async and await)
• Implement IndexedDB Observers
• Ship 8 and 4-digit hex color notation (#RRGGBBAA and #RGBA)
• Deprecate and remove requestAutocomplete method
• Implement and ship CSS font-variant-numeric property
• Experiment durable storage (navigator.storage.persist and .persisted methods)
• Ship Performance Observer API

April 2016

• Ship Web Push protocol and subscription restrictions
• Implement Clear-Site-Data HTTP header
• Implement Generic Sensor and Ambient Light Sensor APIs
• Ship Token Binding
• Ship CSS Containment (contain property)
• Implement CSS hyphens property
• Implement and ship ImageBitmap.close method
• Implement and ship unsafe-dynamic CSP source expression
• Implement and ship IDBKeyRange.includes method
• Implement Storage Quota Estimation API (navigator.storage.estimate())
• Ship ECMAScript 2016 exponentiation operator
• Ship ImageBitmapOptions
• Implement Mediastream Image Capture (e.g. taking pictures from a webcam)
• Implement and ship -webkit-appearance: none for <meter> and <progress> elements
• Ship HTMLMediaElement.srcObject for MediaStreams
• Implement and ship CSS user-select: none (unprefixed)
• Experiment WebUSB
• Ship filters in 2D canvas (CanvasRenderingContext2D.filter property)
• Implement and ship Node.isConnected property

March 2016

• Implement and ship Fetch API Request.referrerPolicy property
• Ship DOM KeyboardEvent.key property
• Implement multiple audio and video tracks
• Ship SameSite attribute for cookies
• Implement inline replies in web notifications
• Implement Visual Viewport API
• Implement and ship notification badges
• Implement multiple image definitions for notifications
• Implement HTMLMediaElement.srcObject for MediaStreams
• Ship iterable array-like interfaces
• Ship Intersection Observer
• Implement and ship “Disallow document.open and document.write during unload”
• Implement “Fire "visibilitychange" event on document unloading”
• Implement <script type="module">
• Ship DOM .rootNode property
• Implement and ship “Correct handling of percentages in children of flex items”
• Implement CORS restrictions on internet-to-intranet connections

February 2016

• Implement Remote Playback API
• Implement and experiment AppInstalled API
• Ship referrerpolicy attribute
• Ship Experimental Framework
• Implement MediaDevices 'devicechange' event
• Implement and ship “Do not use web page-provided strings for 'beforeunload' dialogs”
• Implement CSS @apply rule
• Ship EventListenerOptions.passive
• Implement Payment Request API
• Ship Credential Management API
• Ship Media capture from <canvas> (captureStream method )
• Implement and ship CSS font-variant-caps property
• Implement CSS Snap Size
• Implement and ship Basic InputEvent interface
• Implement and ship CSS :dir() pseudo-class
• Ship Web Animations Level 1, interop with Firefox
• Implement ImageBitmap options
• Implement Non-document root scrollers
• Implement "serviceworker" link relationship
• Implement and ship Optional icon URL for notification actions
• Implement and ship “Merge DOMSettableTokenList into DOMTokenList”
• Experiment Web Bluetooth API
• Implement and ship Notification renotify flag
• Implement Push subscription restrictions and the Web Push protocol
• Implement CSS break-after, break-before, break-inside (generic breaking control)
• Implement and ship “HTMLMediaElement.play() retuns a promise”

January 2016

• Implement and ship "notificationclose" event
• Ship "preload" link relationship
• Implement CSS Paint API
• Ship Brotli (Accept-encoding: br on HTTPS connection)
• Ship Unprefixed CSS Multi-column Layout
• Ship ImageBitmap and createImageBitmap method
• Implement Media Capture from HTMLMediaElement
• Implement and ship CSS column-fill property
• Implement and ship FetchEvent.clientId and Clients.get(id) for Service Worker
• Implement EventListenerOptions.passive
• Ship “Modify {add,remove}EventListener to accept EventListenerOptions”
• Ship Canvas Hit Regions

December 2015

• Implement and ship CSS inverted-colors media feature
• Ship Push messaging payloads (PushEvent.data property)
• Ship CSS Custom Properties Level 1
• Ship i modifier for attribute selectors
• Implement OffscreenCanvas
• Implement and ship Cookie prefixes and Strict Secure Cookies
• Implement Worklets
• Ship Canvas toBlob method
• Ship Promise rejection tracking events

November 2015

• Implement and ship HTMLMediaElement.disableRemotePlayback
• Ship Media Stream Recording API
• Ship Background Sync (one-shot)
• Implement CSS Containment
• Implement and ship addEventListener/removeEventListener non-optional arguments
• Implement and ship DOMTokenList-based feature detection for <link> and <iframe>
• Implement and ship URLSearchParams
• Implement suborigins
• Implement and ship "noopener" link relation

October 2015

• Ship notification action buttons
• Implement and ship "navigate" mode in fetch requests
• Ship Audio Output Devices API
• Implement CSS Typed OM
• Implement “modify addEventListener to accept EventListenerOptions”
• Ship WindowClient.navigate method for service workers

September 2015

• Ship Local Font Access API
• Ship durable storage
• Implement iterable NodeList
• Implement CSS position: sticky
• Implement and ship “Allow data: and blob: schemes in Fetch API”
• Implement CSS font-display
• Ship stale-while-revalidate Cache-control extension

Firefox

October 2024

• Ship Fetch API keepalive option
• Ship beforetoggle and toggle events for the <dialog> element
• Prototype plaintext-only value for HTML contenteditable attribute
• Prototype CSS :local-link pseudo-class
• Prototype CSS :has-slotted pseudo-class

September 2024

• Ship HTML fetchpriority attribute
• Prototype and ship CSS text-emphasis-position: auto value
• Prototype and ship CSS nested declarations rules
• Ship HTMLVideoElement requestVideoFrameCallback method
• Prototype Cookie Store API
• Ship Partitioned attribute for cookies (CHIPS)
• Prototype blocking third-party cookies
• Prototype HTML autocorrect attribute

August 2024

• Ship altitude and azimuth angles for Pointer Events
• Ship WebCodecs
• Prototype View Transitions for single-page apps
• Prototype Network Error Logging

July 2024

• Prototype CSS stretch keyword (and -webkit-fill-available alias)
• Implement HTMLVideoElement requestVideoFrameCallback method

June 2024

• Ship CSS transition-behavior property
• Ship CSS @starting-style rule
• Experiment Privacy-Preserving Attribution
• Prototype CSS field-sizing property
• Prototype HTML popover=hint attribute
• Prototype and ship alt text for the CSS content property
• Ship CSS Relative Color Syntax

May 2024

• Prototype and ship (non-standard) CSS -webkit-font-smoothing property
• Ship CSS Properties and Values API (incl. @property)
• Prototype Partitioned attribute for cookies (CHIPS)
• Prototype bounce tracking nitigations
• Prototype CSS Anchor Positioning

April 2024

• Ship Async Clipboard API read and write methods
• Prototype CSS @starting-style rule
• Prototype CSS @scope rule
• Prototype CSS margin at-rules (such as @top-left)
• Prototype CSS Relative Color Syntax (from keyword)
• Ship CSS zoom property and Element currentCSSZoom property
• Prototype legacy textInput event

March 2024

• Prototype Close Watchers
• Prototype and ship URL.parse static method
• Ship custom state pseudo-class (CustomStateSet interface)
• Prototype Selection direction property and getComposedRanges method, and selections across shadow boundaries
• Prototype element reflection for ARIA relationship attributes (ARIAMixin interface)
• Ship Clipboard readText method
• Ship color interpretation mode in CSS gradients

February 2024

• Prototype and ship CSS align-content property on block containers
• Prototype CSS user-find property

January 2024

• Ship Link headers with rel=preload or rel=modulepreload in HTTP Early Hints responses
• Ship: Fire pointer events on disabled form elements
• Prototype Observable
• Ship Screen Wake Lock API
• Ship Declarative Shadow DOM
• Prototype and ship CSS content-visibility property

December 2023

• Prototype and ship CSS xywh() and rect() basic shapes
• Ship CSS offset-position and offset-path properties
• Ship content-box and stroke-box values for CSS transform-box property

November 2023

• Ship HTML popover attribute
• Preview Declarative ShadowDOM
• Ship Cache API in Private Browsing Mode
• Prototype and ship <hr> elements inside <select> elements
• Prototype Invokers
• Prototype ._internals.states property for exposing custom element states (CustomStateSet)

October 2023

• Prototype and ship HTMLSelectElement showPicker method
• Ship CSS :has() pseudo-class
• Ship Global Privacy Control
• Ship CSS text-wrap: balance value
• Prototype and ship hanging and each-linekeywords for the text-indent CSS property
• Prototype and ship HTML loading=lazy attribute on <iframe> elements
• Ship Early Hints
• Prototype and ship User Activation API
• Prototype and ship CSS lh and rlh units
• Prototype and ship CSS light-dark() color function

September 2023

• Prototype CSS zoom property
• Prototype and ship CSS inheritance to ::backdrop from its originating element (e.g., <dialog>)
• Prototype Screen Wake Lock API
• Prototype Early Hints
• Prototype and ship CSS attr() fallback
• Prototype HTTP Origin-Agent-Cluster header
• Prototype Scroll To Text Fragment
• Prototype CSS text-wrap: balance keyword
• Ship ARIA reflection (non-IDREF) and default accessibility semantics for Custom Elements

August 2023

• Experiment and ship TLS Encrypted Client Hello (ECH)
• Prototype and ship CSS :first pseudo-class
• Implement and ship CSS font-synthesis-position property
• Prototype Global Privacy Control (HTTP Sec-GPC header)
• Prototype CSS :has selector
• Prototype and ship HTML <search> element
• Ship CSS round(), mod(), rem(), pow(), sqrt(), hypot(), log(), exp(), abs(), and sign() functions

July 2023

• Prototype CSS text-transform: math-auto keyword
• Ship CSS math-style and math-depth properties, and font-size: math keyword
• Prototype CSS Custom Highlight API

June 2023

• Prototype CSS Properties and Values API
• Ship Audio Output Devices API
• Prototype and ship CSS Nesting
• Prototype Federated Credential Management (FedCM)
• Implement WebCodecs
• Ship pasting files using ClipboardEvent
• Prototype and ship external hashes (SRI) in Content Security Policy
• Prototype and ship URL.canParse function

May 2023

• Ship CSS animation-composition property
• Ship IndexedDB API in Private Browsing Mode
• Ship modulepreload link relation
• Ship Module Workers
• Prototype and ship HTML dirname attribute (submitting element directionality)
• Ship conditional @import supports() rules
• Ship CSS NaN/infinity in calc()

April 2023

• Prototype CSS transitions of discrete properties
• Prototype conditional @import rules in CSS
• Prototype CSS inverted-colors media feature
• Prototype and ship expanded CSS :lang() selector (incl. wildcard matching)

March 2023

• Ship CSS color-mix() function
• Prototype SVG <discard> element
• Prototype and ship CSS scripting media feature
• Prototype and ship Compression Streams
• Prototype and ship selector argument in CSS :nth-child() and :nth-last-child() pseudo-classes
• Prototype CSS Custom Highlight API
• Prototype CSS prefers-reduced-transparency media feature
• Prototype and ship CSS Color 4 functions (lab(), lch(), oklab(), oklch(), color())
• Prototype Async Clipboard API read and readText with user confirmation
• Ship HTML inert attribute
• Prototype and ship CSS forced-color-adjust property
• Ship CSS linear() easing function

February 2023

• Prototype Screen Orientation lock method on Android and Windows tablet

January 2023

• Prototype and ship CSS size container queries
• Prototype and ship focus fixup rule
• Ship permanently partitioned third-party storage
• Ship HTML autocapitalize attribute
• Ship CSS page property (named pages)
• Prototype WebGPU

December 2022

• Prototype and ship CSP 'unsafe-hashes' source expression
• Prototype CSS page property (named pages)
• Ship scrollend event

November 2022

• Ship WebMIDI (via site permission add-ons)
• Prototype and ship Origin Private File System API

October 2022

• Ship CSS trigonometric functions and constants
• Ship width and height attributes for HTML <source> elements
• Ship CSP script-src-elem, script-src-attr, style-src-elem, style-src-attr directives
• Prototype CSS font-variant-emoji property
• Ship Import Maps
• Prototype Audio Output Devices API
• Prototype and ship CSS font-palette property and @font-palette-values at-rule

September 2022

• Ship CSS contain-intrinsic-size property and its longhands
• Prototype default accessibility semantics for custom elements via the ElementInternals object
• Ship COLRv1 fonts

August 2022

• Prototype Origin Private File System
• Prototype COLRv1 fonts

July 2022

• Ship OffscreenCanvas
• Prototype HTML width and height attributes on <source> elements
• Prototype and ship CSP script-src-elem and script-src-attr directives
• Prototype and ship Canvas 2D context fontKerning property
• Prototype CSS animation-composition property

June 2022

• Ship Transferable Streams
• Ship CSS scroll-snap-stop property
• Prototype CSS linear() easing function

May 2022

• Ship CSS constructable stylesheets
• Prototype Transferable Streams
• Ship TransformStream and ReadableStream pipeThrough method

April 2022

• Ship CSS small (sv*), large (lv*), dynamic (dv*), and logical (vi, vb) viewport units
• Ship CSS prefers-contrast media feature
• Prototype and ship HTMLInputElement showPicker method
• Prototype TransformStream and ReadableStream pipeThrough method
• Prototype Largest Contentful Paint
• Prototype Import Maps

March 2022

• Prototype CSS content-visibility: hidden value

January 2022

• Ship Readable Streams (new implementation)
• Ship relaxed cache re-validation on a soft reload (don’t re-validate subresources)
• Ship CSS hyphenate-character property
• Ship form-associated custom elements
• Ship HTML <dialog> element

December 2021

• Ship CSS scrollbar-gutter property
• Prototype CSS hyphenate-character property
• Ship CSS d property
• Prototype OffscreenCanvas interface
• Ship SameSite=Lax cookie attribute by default

November 2021

• Prototype and ship CSS hwb() function (HWB Colors)
• Ship Web Locks API
• Ship reversed() functional notation for the CSS counter-reset property

October 2021

• Ship CSS size property in @page rules
• Ship partitioned third-party service workers
• Ship HTML inputmode attribute on desktop
• Prototype Prioritized Task Scheduling
• Prototype URL Query String Stripping
• Prototype and ship CSS input-security property
• Prototype and ship structuredClone function

September 2021

• Ship HTML enterkeyhint attribute
• Prototype CSS size property for @page
• Prototype Scroll-linked Animations
• Prototype and ship <input type=datetime-local> on desktop
• Prototype and ship CSS SelectedItem and SelectedItemText system colors
• Prototype and ship smooth and pixelated values for the CSS image-rendering property
• Ship ShadowRoot delegatesFocus property
• Prototype CSS @layer at-rule

August 2021

• Ship "HTTPS" DNS resource record (HTTPS RR)
• Prototype Web Locks API
• Prototype and ship reportError function
• Ship avoid-page and avoid-column values for CSS break-inside property
• Prototype and ship CSS system-ui generic font family name
• Ship disabledFeatures static method for custom element classes

July 2021

• Prototype and ship CSS accent-color property
• Ship assign method for <slot> element
• Ship CSS size-adjust descriptor and extended syntax of the font-size-adjust property

June 2021

• Ship CSS font-synthesis: small-caps value
• Ship CSS content: none on elements
• Ship CSS content: none on ::marker pseudo-elements
• Ship CSS tab-size property
• Ship Implicit Pointer Capture

May 2021

• Ship Visual Viewport API on desktop platforms
• Ship HTTP Ship Sec-Fetch-* headers (Fetch Metadata Request Headers)
• Prototype CSS d property on SVG <path> elements
• Prototype JPEG XL image format (limited support)

April 2021

• Prototype and ship relaxed cache re-validation on soft reload
• Prototype and ship EXIF image density correction
• Ship CSS ascent-override, descent-override, and line-gap-override font descriptors
• Ship CSS forced-colors media feature (née prefers-contrast)

March 2021

• Prototype and ship inferred aspect-ratio from width/height attributes for <video>, <canvas> and <input type=image>
• Prototype CSS ascent-override, descent-override, and line-gap-override font descriptors
• Prototype CSS glyph-scale-factor/size-adjust descriptor
• Ship AbortSignal.abort() for creating an aborted AbortSignal
• Ship AV1 Image File Format (AVIF)
• Ship CSS aspect-ratio property
• Prototype CSS fit-content() function

February 2021

• Ship outlines that follow border-radius
• Prototype CSS color-mix() function
• Prototype and ship CSS :user-valid and :user-invalid pseudo-classes
• Prototype outlines that follow border-radius

January 2021

• Ship beforeinput event and its getTargetRanges method
• Ship CSS :autofill pseudo-class

December 2020

• Ship Network Partitioning (incl. storage and HTTP cache partitioning)
• Ship strict-origin-when-cross-origin as default referrer policy
• Prototype CSS :autofill pseudo-class
• Unship <menu type=context>, <menuitem>, and contextMenu property (HTML context menus)
• Prototype and ship signal option for addEventListener method (AbortSignal)

November 2020

• Implement and ship CSS touch-action: pinch-zoom value
• Ship CSS :focus-visible pseudo-class

October 2020

• Prototype and ship localhost addresses as secure contexts (“potentially trustworthy”)
• Ship CSS conic-gradient() notation

September 2020

• Ship Media Session API
• Prototype CSS math-style property
• Ship beforeinput event and its getTargetRanges method
• Prototype better error recovery for CSS :is() and :where() pseudo-classes
• Prototype TLS Encrypted Client Hello
• Prototype HTML autocapitalize attribute
• Ship allow-downloads keyword for the <iframe sandbox> attribute
• Ship CSS ::file-selector-button pseudo-element

August 2020

• Ship selectionchange event for <input> and <textarea> elements
• Prototype WebXR Layers
• Ship Redirect Tracking Protection

July 2020

• Ship CSS overflow: clip value
• Unship CSS ::-moz-focus-outer pseudo-element
• Ship composite modes for animations
• Prototype Payment Handler API
• Prototype Sanitizer API
• Ship CSS appearance property (unprefixed)
• Prototype CSS cross-fade() function
• Prototype CSS prefers-contrast media feature
• Prototype unprefixed CSS appearance property

June 2020

• Ship in Nightly HTML <dialog> element
• Prototype HTML inert attribute
• Prototype enterkeyhint attribute

May 2020

• Ship DOM replaceChildren method
• Ship <link rel=preload>
• Prototype CSS aspect-ratio property
• Prototype CSS ::file-chooser-button pseudo-element
• Prototype Schemeful Same-Site (http://example.com and https://example.com considered cross-site)
• Ship CSS :read-only and :read-write pseudo-classes

April 2020

• Prototype Dynamic First-Party Isolation
• Prototype and ship CSS :is() and :where() pseudo-classes
• Ship AudioWorklet
• Prototype ARIA reflection

March 2020

• Prototype and ship “Defer <script defer> execution until all script-blocking stylesheets are loaded”
• Unship FTP protocol
• Ship getAnimations method for the Element and Document interfaces

February 2020

• Prototype and ship ARIA suggestion, mark, and comment roles and aria-description attribute (ARIA annotations)
• Prototype CSS :focus-visible pseudo-class
• Prototype and ship CSS min(), max(), and clamp() functions
• Implement CSS conic-gradient() notation
• Prototype and ship <img loading> attribute (for lazy-loading images)
• Ship submit event (contains submitter property)
• Ship <form> requestSubmit method

January 2020

• Prototype masonry layout in CSS Grid
• Ship CSS outline-style: auto value
• Implement AVIF image format (based on the AV1 video codec)
• Ship HTTP Cross-Origin-Resource-Policy header
• Prototype beforeinput event
• Ship CSS text-underline-position property

December 2019

• Implement and ship CSS overscroll-behavior-inline and overscroll-behavior-block properties
• Prototype and ship IDBTransaction commit method
• Prototype CSS text-underline-position property
• Prototype Navigation Preload for Service Worker
• Prototype Constructable Stylesheet Objects

November 2019

• Prototype delegated permissions for third-party iframes via the allow attribute
• Ship CSS Shadow Parts
• Ship CSS translate, scale, and rotate properties (individual transforms)
• Ship CSS Motion Paths
• Ship user interaction requirement for notification permission prompts

October 2019

• Ship CSS subgrid layout
• Experiment heading level based on outline depth
• Ship CSS column-span property
• Experiment Web Speech API
• Experiment Web Share Target
• Ship: Infer aspect-ratio from image width/height attributes

September 2019

• Ship CSS text-decoration-skip-ink, text-decoration-thickness, and text-underline-offset properties
• Ship event-based form participation (incl. formdata event)
• Ship X-Content-Type-Options: nosniff for navigations

August 2019

• Ship CSS clip-path: path() values
• Implement double-keyed HTTP cache
• Ship multi-keyword values for the CSS display property
• Ship inline list-item and inline flow-root list-item values for the CSS display property
• Ship block ruby value for the CSS display property
• Ship CSS font-size: xxx-large value
• Implement CSS text-decoration-skip-ink property

July 2019

• Implement CSS text-decoration-width property
• Ship percentage opacity values in CSS
• Implement and ship CSS quotes: auto value
• Implement CSS backdrop-filter property
• Experiment Web Share API

June 2019

• Experiment: Infer aspect-ratio from image width/height attributes
• Ship CSS @supports selector() function
• Implement and ship webkitURL constructor (legacy compatibility alias of URL)
• Implement and ship CSS white-space: break-spaces value
• Implement and ship Resize Observer API
• Implement CSS text-decoration-width property
• Implement CSS text-underline-offset property
• Implement and ship CSS overflow-block and overflow-inline properties
• Implement and ship text, arrayBuffer, and stream methods on Blob interface

May 2019

• Implement and ship queueMicrotask function
• Implement changes to cookies (add SameSite=Lax by default, require Secure for SameSite=None)
• Implement CSS line-break property
• Ship Visual Viewport API on Android

April 2019

• Implement and ship noreferrer feature for window.open method
• Implement and ship <link rel="stylesheet" disabled> attribute
• Implement and ship preventScroll option for the focus method

March 2019

• Implement and ship CSS ::marker pseudo-element
• Implement and ship CSS counter-set property
• Ship CSS contain property
• Ship JavaScript import() syntax for dynamic imports
• Implement and ship CSS revert keyword
• Implement and ship CSS Scroll Snap

February 2019

• Implement and ship CSS prefers-color-scheme media feature
• Implement CSS -webkit-line-clamp property
• Implement and ship InputEvent data and dataTransfer properties

January 2019

• Ship implicit rel="noopener" for <a target="_blank"> elements
• Implement and ship CSS border-block-color, etc. properties and shorthands
• Implement and ship CSS border-start-start-radius, etc. properties
• Implement and ship CSS inset, inset-block, and inset-inline shorthands
• Implement and ship CSS margin-block and margin-inline shorthands
• Implement and ship CSS padding-block and padding-inline shorthands
• Implement HTTP Report-To header (part of Reporting API)

December 2018

• Implement and ship CSS overflow-inline and overflow-block media features
• Ship Storage Access API
• Ship InputEvent inputType property
• Implement and ship s modifier for attribute selectors
• Implement and ship CSS break-before, break-after, and break-inside properties

November 2018

• Ship no "keypress" events when pressed key does not introduce text input
• Ship "keydown" and "keyup" events during IME composition
• Implement implicit rel="noopener" for <a target="_blank"> elements
• Implement CSS Scroll Anchoring
• Implement Reporting API (ReportingObserver)
• Implement and ship CSS overflow-wrap: anywhere value
• Implement and ship image decode method
• Implement and ship CSS env() notation (environment variables)

October 2018

• Implement <script referrerpolicy> attribute
• Implement JavaScript import() syntax for dynamic imports
• Implement and ship screenLeft and screenTop properties (aliases for screenX and screenY)
• Implement CSS @supports selector function
• Implement and ship WebP image format

September 2018

• Ship CSS scrollbar-color and scrollbar-width properties
• Implement and ship new cookie jar policy to block storage access from tracking resources
• Implement and ship navigator.getDisplayMedia method (Screen Capture)
• Ship unprefixed Fullscreen API
• Implement Feature Policy
• Implement Storage Access API

August 2018

• Implement: “Treat -webkit- prefixed pseudo elements as valid CSS selectors”
• Ship Custom Elements and Shadow DOM
• Implement and ship block and inline values for the CSS resize property
• Ship CSS -webkit-appearance property
• Ship Async Clipboard API
• Implement CSS scrollbar-width property
• Implement CSS Motion Paths
• Implement and ship WebXR Device API (successor to WebVR)
• Implement and ship HTMLMediaElement allowedToPlay property
• Implement Visual Viewport API

July 2018

• Implement and ship <img decoding> attribute
• Implement and ship CSS prefers-reduced-motion media feature (on Windows and macOS)
• Ship HTTP Clear-Site-Data header
• Ship Web Animations API (core interfaces)
• Implement CSS scrollbar-face-color and scrollbar-track-color properties

June 2018

• Ship DOM Element toggleAttribute method
• Ship range context for CSS media queries (with limitations)
• Ship Storage API on Android (persist and estimate methods)
• Implement HTTP Clear-Site-Data header
• Ship CSS shape-outside property

May 2018

• Ship speech synthesis on Android (part of Web Speech API)
• Implement and ship import.meta meta property in module scripts
• Ship Media Capabilities API
• Implement Async Clipboard API
• Implement AudioWorklet interface (Web Audio API)
• Ship Event srcElement property (alias of target property)

April 2018

• Ship Server Timing
• Implement application/javascript+binast (JavaScript Binary AST content encoding)
• Ship CSS overflow shorthand (accepts two values)
• Implement CSS subgrid layout (prototype)
• Implement and ship SameSite attribute for cookies

March 2018

• Ship OpenType variable fonts

February 2018

• Ship module scripts (<script type="module">)
• Implement and ship navigator.webdriver (Boolean) property
• Ship CSS paint-order property for HTML text

January 2018

• Ship CSS overscroll-behavior property

December 2017

• Implement CSS paint-order property for HTML text
• Remove Ambient Light and Proximity Sensor APIs
• Implement CSS translate, scale, and rotate properties (individual transforms)
• Ship Web Authentication API (initially for FIDO U2F tokens)

November 2017

• Ship CSS Shapes
• Implement Custom Elements v1
• Implement Shadow DOM v1
• Ship stricter X-Frame-Options: SAMEORIGIN (check all ancestor frames)
• Ship WebVTT regions
• Implement and ship (subclassable) EventTarget constructor
• Ship CSP violation events

October 2017

• Implement CSS overscroll-behavior property
• Ship Pointer Events on desktop
• Unship preload link relation (temporary)
• Ship "navigation" performance entry (replacement for navigation.timing)
• Ship “throttle timeouts in background tabs”
• Implement and ship Resource Timing workerStart property
• Implement CSS interaction media features (pointer, hover, any-pointer, any-hover)
• Ship <a ping> attribute

September 2017

• Ship WebVR on macOS
• Ship Performance Observer API

August 2017

• Ship Abort API (AbortController)
• Ship CSS font-display descriptor

July 2017

• Ship preload link relation

May 2017

• Ship HTTP SourceMap response header

March 2017

• Implement CSS line-height-step property
• Implement and ship CSS ::cue pseudo-element
• Implement ScrollTimeline API (for creating scroll-linked animations)
• Ship Intersection Observer
• Ship CSS frames() timing function
• Ship CSS text-justify property
• Ship CSS transform-box property
• Ship WebVR (on Windows)

February 2017

• Implement CSS frames() timing function
• Implement and ship CSS animationcancel event
• Implement and ship global origin property (self.origin)
• Implement CSS text-justify property
• Ship basic shape values for CSS clip-path property (inset(), circle(), ellipse(), polygon())

January 2017

• Ship new syntax of CSS color functions (e.g. rgb(0 0 0 / 100%))
• Implement and ship HTTP Large-Allocation header (non-standard)
• Implement module scripts (<script type="module">)
• Experiment CSS Houdini Paint API Level 1

December 2016

• Implement CSS box alignment properties on block containers
• Implement SVG vector-effect property (additional values)
• Implement and ship CSS caret-color property
• Implement HTML5 <dialog> element
• Implement and ship CSS display: flow-root value
• Implement and ship Selection setBaseAndExtent method
• Ship CSS mask-image property (repeated intent)
• Ship Network Information API
• Implement “Store IndexedDB databases for the lifetime of private browsing sessions”
• Implement OpenType variable fonts
• Ship Presentation API (on Android)

November 2016

• Implement Web2Native Bridge
• Implement CSS background-repeat-x/background-repeat-y and mask-repeat-x/mask-repeat-y properties
• Implement Payment Request API
• Ship CSS Grid Layout
• Implement and ship Web Authentication API
• Ship requestIdleCallback function

October 2016

• Implement and ship transitionrun, transitionstart, and transitioncancel events
• Ship TLS 1.3 (draft 16)
• Implement CSS shape-outside property
• Ship Selection API events (selectionstart, selectionchange)
• Ship CSS touch-action property (only Level 1 values)

September 2016

• Implement CSS initial-letter property
• Implement and ship global isSecureContext property in workers
• Ship Storage API estimate method
• Implement Canvas 2d context getTransform/setTransform methods

August 2016

• Ship Canvas 2D context imageSmoothingEnabled property
• Implement transitionstart event
• Implement and ship HTML minlength attribute and tooShort validity state
• Implement and ship dataset API on SVG elements

July 2016

• Implement and ship forEach method on NodeList and DOMTokenList
• Ship Blink’s Entries API (webkitGetAsEntry method) incl. file input webkitdirectory attribute
• Ship (unprefixed) CSS :any-link pseudo-class
• Implement MediaDevices devicechange event
• Implement and ship MediaStreamTrack getConstraints and getSettings methods
• Implement CSS Properties and Values API
• Implement and ship once option for addEventListener method
• Implement and ship __Secure-/__Host- cookie prefixes
• Ship CSS touch-action property
• Implement and ship “Force flattening of transform-style: preserve-3d when opacity is applied”

June 2016

• Implement and ship Service Worker WindowClient.navigate method
• Ship CSS mask-image property

May 2016

• Ship filters in 2D canvas
• Ship unprefixed CSS text-align-last property
• Implement and ship HTMLMediaElement seekToNextFrame method (non-standard)
• Ship PerformanceObserver API
• Unship HTML microdata API
• Implement and ship space/round values for CSS background-repeat property
• Ship unprefixed CSS :dir pseudo-class
• Implement and ship 8 and 4-digit hex color notation (#RRGGBBAA and #RGBA)
• Implement and ship “sandbox propagates to auxiliary browsing contexts” flag (allow-popups-to-escape-sandbox keyword)
• Implement and ship “sandboxed modals” flag (allow-modals keyword)
• Implement and ship passive event listeners (passive option)
• Implement and ship DOMTokenList.prototype.supports property

April 2016

• Ship Speech Synthesis API
• Implement and ship "noopener" link relation
• Ship “Restrict geolocation.watchPosition to secure contexts”
• Ship basic shapes (polygon et al) for CSS clip-path property
• Implement requestIdleCallback function
• Ship Element.animate method
• Ship ParentNode prepend, append, before, after, replaceWith methods
• Ship document.scrollingElement property
• Ship “Treat cookies set over non-secure HTTP as session cookies”
• Ship HTML <details> and <summary> elements
• Implement and ship CSS -webkit-text-stroke property

March 2016

• Implement CSS -webkit-background-clip: text
• Implement and ship CSS text-combine-upright: all
• Ship navigator.hardwareConcurrency
• Implement Credential Management API
• Ship CSS color-adjust property
• Implement Push API in Firefox for Android

February 2016

• Implement and ship IDBKeyRange.includes()
• Implement and ship fetch() referrer and Referrer Policy API

January 2016

• Implement and ship document.elementsFromPoint method

December 2015

• Implement and ship Support for a subset of -webkit- prefixed CSS properties and features
• Implement One-off Background Sync API
• Ship referrerpolicy attribute
• Implement and ship FIDO U2F API

November 2015

• Ship Service Workers with FetchEvent
• Implement HTML <details> and <summary> elements
• Implement and ship Performance.translateTime method
• Ship CSS unicode-range descriptor
• Implement and ship CSS Emphasis Marks (text-emphasis property)
• Ship CSS Mask Image properties
• Ship Web Speech API - Synthesis

October 2015

• Ship WebVR
• Implement and ship window.orientation and 'orientationchange' event
• Implement and ship ::backdrop pseudo-element for Fullscreen API