HTML & Media
- <meta name=theme-color>
- <fencedframe>
- <portal>
- iframe credentialless
- focusgroup
- contenteditable=plaintext-only attribute
- URL Fragment Text Directives
- JPEG XL images
- SVG favicons
- AV1 videos
- <model>
- interactive-widget
- is attribute
- <input type=checkbox switch>
- <script blocking>
- stylable <select>
- <meta name=app-title>
- <link rel=expect>
- writingsuggestions attribute
- shadowrootclonable attribute
- shadowrootdelegatesfocus attribute
- shadowrootserializable attribute
- <meta name=theme-color>
CSS
- mask-border
- print-color-adjust
- user-select
- text-size-adjust
- box-decoration-break
- text-decoration
- -webkit-text-fill-color
- -webkit-text-stroke
- -webkit-text-security
- cross-fade()
- line-clamp
- element()
- -webkit-box-reflect
- {inline, block}-size: stretch
- initial-letter
- hyphenate-limit-lines
- line-grid
- line-snap
- mask-position-{x, y}
- -webkit-canvas()
- margin-trim
- :host-context()
- view transitions
- @view-transition
- :active-view-transition
- :active-view-transition-type()
- view-transition-class
- filter()
- currentColor in relative color syntax
- transition-behavior
- @page
- masonry layout
- anchor positioning
- gradient color spaces
- overflow-{block, inline}
- overflow-clip-margin
- @container style()
- scroll progress timelines
- view progress timelines
- hanging-punctuation
- sign-related functions (abs(), sign())
- clip-path: external SVGs
- COLRv1 fonts
- forced-color-adjust
- font-family: ui-{serif, sans-serif, monospace, rounded}
- d: path()
- text-indent: {hanging, each-line}
- object-view-box
- scrollbar-color
- scrollbar-width
- ::-webkit-scrollbar
- ::-webkit-slider-runnable-track
- ::-webkit-slider-thumb
- ::-moz-range-track
- ::-moz-range-thumb
- ::-moz-range-progress
- math-shift
- math-depth
- orphans, widows
- overlay
- scrollbar-gutter
- text-justify
- toggle
- {rex, rch, cap, rcap, ric} units
- ::spelling-error, ::grammar-error
- @scope
- field-sizing
- {align, justify}-{content, self, items}: safe/unsafe
- text-wrap-mode
- text-wrap-style
- text-wrap: pretty
- text-wrap: stable
- interpolate-size
- calc-size()
- new highlight inheritance
- line-grid
- @page margin boxes
- page-based counters
- column combinator
- :nth-col(), :nth-last-col()
- @custom-media
- toggle()
- cascade control
- linked parameters
- @extend
- content-size
- @filter
- ::slotted()
- scroll-start-target
- :snapped
- sign-related functions in calc()
- src()
- @when, @else
- :local-link
- :target-within
- :current, :past, :future
- :playing, :paused, :seeking
- :buffering, :stalled
- :muted, :volume-locked
- @supports at-rule()
- CSS extensions
- variable units
- focus-group
- caret-shape
- copy-into
- exclusions (wrap-flow & wrap-through)
- regions (flow-into & flow-from)
- rhythmic sizing
- mask-border
JavaScript APIs
- speech recognition
- File and Directory Entries API
- HTMLSelectElement.prototype.showPicker()
- custom highlight
- canvas color spaces
- CSS typed object model
- file system access
- FileSystemObserver
- file handling
- navigator.userAgentData
- WebGPU
- Navigation
- URLPattern
- local font access
- EyeDropper
- HID
- USB
- Serial
- Bluetooth
- background fetch
- handwriting recognition
- background sync
- periodic background sync
- WebTransport
- WebXR
- document.caretPositionFromPoint
- document.caretRangeFromPoint (non-standard)
- barcode detection
- face detection
- text detection
- requestIdleCallback
- MIDI
- custom protocol handling
- beforeinstallprompt event
- navigator.share()
- navigator.share(): files
- share target
- background blur
- ScrollTimeline
- animation worklet
- Painting API
- Layout API
- document.fragmentDirective
- document.fragmentDirective.createSelectorDirective()
- EditContext API
- Web Neural Network API
- Model Loader API
- contentvisibilityautostatechange event
- scrollend event
- navigator.vibrate()
- ambient light sensor
- badging
- deviceorientationabsolute event
- clipboard web custom formats
- compute pressure
- contact picker
- Content Index
- WebCodecs: video
- WebCodecs: audio
- CookieStore
- battery status
- Idle Detection
- is input pending
- JS Self-Profiling
- measure memory
- documentPicutreInPicuture
- Preferences API
- CloseWatcher
- Document.parseHTMLUnsafe, {Element, ShadowRoot}.prototype.setHTMLUnsafe
- Observable
- custom element disabledFeatures
- pagereveal event
- service worker: InstallEvent.prototype.addRoutes()
- Element.prototype.currentCSSZoom
- {Request, Response}.prototype.bytes()
- Blob.prototype.bytes()
- Sanitizer
- navigator.storage.estimate(): usageDetails
- WebXR WebGPU binding
- folder handling
- PDF generation
- requestPostAnimationFrame()
- Color
- CSS.customMedia()
- spatial navigation
- {snapchanged, snapchanging} event
- layout transition primitives
- CSS Parser API
- Font Metrics API
- Box Tree API
- speech recognition
ECMAScript
WebAssembly
Web features
This site provides an overview of many web features that are not yet fully supported (unprefixed) in all three major browser engines. These range from features already implemented in two browser engines up to unofficial drafts and even just proposals. The three major browser engines are:
| Logo | Browser engine | Associated browser | Company |
 | Blink | Chrome/ | |
 | WebKit | Safari | Apple |
 | Gecko | Firefox | Mozilla |
Legend
| Icon | Description |
| The feature is supported in the current stable version of the associated browser. | |
| The feature is experimentally supported in a developer preview version of the associated browser. A special flag might need to be enabled. | |
| The feature uses a non-standard, vendor-prefixed name. | |
| The feature has limited support (e.g. not available on all platforms) |