Features missing only in Safari
The following features are implemented in all other browser engines, but not in Safari.
-
Asynchronously iterable streams
Limited availabilityAsynchronous iteration of a stream allows you to use
for await … ofloops to iterate through a stream's incoming data.- Chrome 124 Released on 2024-04-16
- Chrome Android 124 Released on 2024-04-16
- Edge 124 Released on 2024-04-18
- Firefox 110 Released on 2023-02-14
- Firefox for Android 110 Released on 2023-02-14
- Safari Not supported Position: support
- Safari on iOS Not supported Position: support
Baseline availability blocked since April 2024 by Safari (27 months)
-
autocapitalize
Limited availabilityThe
autocapitalizeglobal HTML attribute sets the virtual keyboard capitalization behavior for user input on an element, such as the first letter of sentences or all words.- Chrome 66 Released on 2018-04-17
- Chrome Android 66 Released on 2018-04-17
- Edge 79 Released on 2020-01-15
- Firefox 111 Released on 2023-03-14
- Firefox for Android 111 Released on 2023-03-14
- Safari Not supported
- Safari on iOS 10.3 Released on 2017-03-27
Baseline availability blocked since March 2023 by Safari (40 months)
-
background-attachment
Limited availabilityThe
background-attachmentCSS property sets whether an element's background image or gradient moves as the element scrolls.- Chrome 1 Released on 2008-12-11
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 25 Released on 2013-10-29
- Firefox for Android 25 Released on 2013-10-29
- Safari 15.4 Released on 2022-03-14
- Safari on iOS Not supported
Baseline availability blocked since March 2022 by Safari (52 months)
-
baseline-source
Limited availabilityThe
baseline-sourceCSS property controls how inline-level boxes with multiple lines of text are aligned with the surrounding text. By default, which typographic baseline is used depends on thedisplayproperty value.- Chrome 111 Released on 2023-03-07
- Chrome Android 111 Released on 2023-03-07
- Edge 111 Released on 2023-03-13
- Firefox 115 Released on 2023-07-04
- Firefox for Android 115 Released on 2023-07-04
- Safari Not supported Position
- Safari on iOS Not supported Position
Baseline availability blocked since July 2023 by Safari (36 months)
-
beforeunload
Limited availabilityThe
beforeunloadevent is fired when the current window is about to be unloaded. Typically this is used to display a dialog to confirm if users really want to leave the page when there is unsaved data that would be lost.- Chrome 1 Released on 2008-12-11
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 1 Released on 2004-11-09
- Firefox for Android 4 Released on 2011-03-29
- Safari 3 Released on 2007-10-26
- Safari on iOS Not supported
Baseline availability blocked since July 2015 by Safari (132 months)
-
box-decoration-break
Limited availabilityThe
box-decoration-breakCSS property sets whether box decorations, such as borders or backgrounds, of an element divided across a page, column, or region wraps each fragment or splits across the break.- Chrome 130 Released on 2024-10-15
- Chrome Android 130 Released on 2024-10-15
- Edge 130 Released on 2024-10-17
- Firefox 32 Released on 2014-09-02
- Firefox for Android 32 Released on 2014-09-02
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since October 2024 by Safari (21 months)
-
2D canvas opacity
Limited availabilityThe optional
alphaparameter of a 2D canvas'sgetContext()method sets whether the canvas has an alpha transparency channel. If set tofalse, then this permits the browser to optimize compositing for an opaque canvas.- Chrome 32 Released on 2014-01-14
- Chrome Android 32 Released on 2014-01-15
- Edge 79 Released on 2020-01-15
- Firefox 30 Released on 2014-06-10
- Firefox for Android 30 Released on 2014-06-10
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2020 by Safari (78 months)
-
contextlost and contextrestored
Limited availabilityThe
contextlostevent for<canvas>fires when the canvas backing storage is lost, while thecontextrestoredevent fires when it is recreated.- Chrome 99 Released on 2022-03-01
- Chrome Android 99 Released on 2022-03-01
- Edge 99 Released on 2022-03-03
- Firefox 125 Released on 2024-04-16
- Firefox for Android 125 Released on 2024-04-16
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2024 by Safari (27 months)
-
captureStream() for <audio> and <video>
Limited availabilityThe
captureStream()method for<audio>and<video>elements returns aMediaStreamfor the media element's content. You can use this to record media or send it elsewhere, such as a canvas or WebRTC connection.- Chrome 62 Released on 2017-10-17
- Chrome Android 62 Released on 2017-10-24
- Edge 79 Released on 2020-01-15
- Firefox 149 Released on 2026-03-24
- Firefox for Android 149 Released on 2026-03-24
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since March 2026 by Safari (4 months)
-
CloseWatcher
Limited availabilityThe
CloseWatcherAPI listens and responds to close requests on in-page components, such as modals, popovers, and sidebars.- Chrome 126 Released on 2024-06-11
- Chrome Android 126 Released on 2024-06-11
- Edge 126 Released on 2024-06-13
- Firefox 149 Released on 2026-03-24
- Firefox for Android 149 Released on 2026-03-24
- Safari Not supported Position: neutral
- Safari on iOS Not supported Position: neutral
Baseline availability blocked since March 2026 by Safari (4 months)
-
COLRv1
Limited availabilityCOLRv1 is a font format that supports multi-color glyphs. COLRv1 extends COLRv0 to support gradients, transforms, and blending modes.
- Chrome 98 Released on 2022-02-01
- Chrome Android 98 Released on 2022-02-01
- Edge 98 Released on 2022-02-03
- Firefox 107 Released on 2022-11-15
- Firefox for Android 107 Released on 2022-11-15
- Safari Not supported Position
- Safari on iOS Not supported Position
Baseline availability blocked since November 2022 by Safari (44 months)
-
context-fill and context-stroke
Limited availabilityThe
context-fillandcontext-strokeCSS values are used withfillandstrokein SVG<marker>or<use>elements to match a color from where they appear.- Chrome 124 Released on 2024-04-16
- Chrome Android 124 Released on 2024-04-16
- Edge 124 Released on 2024-04-18
- Firefox 111 Released on 2023-03-14
- Firefox for Android 111 Released on 2023-03-14
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2024 by Safari (27 months)
-
CSS import attributes
Limited availabilityModule
import … with { type: "css" }statements load CSS modules as constructable stylesheets. Also known as CSS module scripts.- Chrome 123 Released on 2024-03-19
- Chrome Android 123 Released on 2024-03-19
- Edge 123 Released on 2024-03-22
- Firefox 147 Released on 2026-01-13
- Firefox for Android 147 Released on 2026-01-13
- Safari Not supported Position: support
- Safari on iOS Not supported Position: support
Baseline availability blocked since January 2026 by Safari (6 months)
-
Cursor styles
Limited availabilityThe
cursorCSS property styles the pointer, allowing you to provide hints to the user on how to interact with the hovered element.- Chrome 68 Released on 2018-07-24
- Chrome Android 68 Released on 2018-07-24
- Edge 79 Released on 2020-01-15
- Firefox 27 Released on 2014-02-04
- Firefox for Android 95 Released on 2021-12-07
- Safari 11 Released on 2017-09-19
- Safari on iOS Not supported
Baseline availability blocked since December 2021 by Safari (55 months)
-
Customized built-in elements
Limited availabilityCustomized built-in elements are HTML elements that extend built-in elements using the
isattribute, to add new behaviors that you define.- Chrome 67 Released on 2018-05-29
- Chrome Android 67 Released on 2018-05-31
- Edge 79 Released on 2020-01-15
- Firefox 63 Released on 2018-10-23
- Firefox for Android 63 Released on 2018-10-23
- Safari Not supported Position: oppose
- Safari on iOS Not supported Position: oppose
Baseline availability blocked since January 2020 by Safari (78 months)
-
devicePixelRatio
Limited availabilityThe
window.devicePixelRatioproperty is the ratio of the size of one CSS pixel to the vertical size of one physical pixel on the current display device.- Chrome 1 Released on 2008-12-11
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 18 Released on 2013-01-08
- Firefox for Android 18 Released on 2013-01-08
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2015 by Safari (132 months)
-
<dialog closedby>
Limited availabilityThe
closedbyHTML attribute for<dialog>sets which user actions close a dialog. For example,closedby="any"allows the dialog to be closed by clicking outside of it.- Chrome 134 Released on 2025-03-04
- Chrome Android 134 Released on 2025-03-04
- Edge 134 Released on 2025-03-06
- Firefox 141 Released on 2025-07-22
- Firefox for Android 141 Released on 2025-07-22
- Safari Not supported Position: support
- Safari on iOS Not supported Position: support
Baseline availability blocked since July 2025 by Safari (12 months)
-
Explicit resource management
Limited availabilityThe
usingandawait usingdeclarations and thedisposeandasyncDisposesymbols manage the lifecycle of resources such as file handles and streams. TheDisposableStackandAsyncDisposableStackobjects can group, dispose, and coordinate dependencies between multiple disposable resources.- Chrome 134 Released on 2025-03-04
- Chrome Android 134 Released on 2025-03-04
- Edge 134 Released on 2025-03-06
- Firefox 141 Released on 2025-07-22
- Firefox for Android 141 Released on 2025-07-22
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2025 by Safari (12 months)
-
EXT_float_blend WebGL extension
Limited availabilityThe
EXT_float_blendextension for WebGL 1.0 and 2.0 contexts adds 32-bit floating-point components to blending and draw buffers.- Chrome 75 Released on 2019-06-04
- Chrome Android 75 Released on 2019-06-04
- Edge 79 Released on 2020-01-15
- Firefox 67 Released on 2019-05-21
- Firefox for Android 67 Released on 2019-05-21
- Safari 14.1 Released on 2021-04-26
- Safari on iOS Not supported
Baseline availability blocked since April 2021 by Safari (63 months)
-
The
window.external.AddSearchProvider()andwindow.external.IsSearchProviderInstalled()do nothing. Historically, they added external search providers to the browser.- Chrome 9 Released on 2011-02-03
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 2 Released on 2006-10-24
- Firefox for Android 4 Released on 2011-03-29
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2015 by Safari (132 months)
-
Fetch metadata request headers
Limited availabilityThe
Sec-Fetch-Dest,Sec-Fetch-Mode,Sec-Fetch-Site, andSec-Fetch-UserHTTP headers provide extra information about the way a request was made, to help servers reject certain kinds of malicious requests.- Chrome 80 Released on 2020-02-04
- Chrome Android 80 Released on 2020-02-04
- Edge 80 Released on 2020-02-07
- Firefox 90 Released on 2021-07-13
- Firefox for Android 90 Released on 2021-07-13
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2021 by Safari (60 months)
-
font-language-override
Limited availabilityThe
font-language-overrideCSS property sets which language-specific glyphs are displayed.- Chrome 143 Released on 2025-12-02
- Chrome Android 143 Released on 2025-12-02
- Edge 143 Released on 2025-12-05
- Firefox 34 Released on 2014-12-01
- Firefox for Android 34 Released on 2014-12-01
- Safari Not supported Position
- Safari on iOS Not supported Position
Baseline availability blocked since December 2025 by Safari (7 months)
-
Font metric overrides
Limited availabilityThe
ascent-override,descent-override, andline-gap-overridedescriptors adjust the display of a font declared in an@font-facestatement. This can help make fallback fonts look the same size.- Chrome 87 Released on 2020-11-17
- Chrome Android 87 Released on 2020-11-17
- Edge 87 Released on 2020-11-19
- Firefox 89 Released on 2021-06-01
- Firefox for Android 89 Released on 2021-06-01
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since June 2021 by Safari (61 months)
-
font-variant-emoji
Limited availabilityThe
font-variant-emojiCSS property sets the default presentation for emoji characters.- Chrome 131 Released on 2024-11-12
- Chrome Android 131 Released on 2024-11-12
- Edge 131 Released on 2024-11-14
- Firefox 141 Released on 2025-07-22
- Firefox for Android 141 Released on 2025-07-22
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2025 by Safari (12 months)
-
Fullscreen API
Limited availabilityThe fullscreen API makes a specific element fill the whole screen and hides most browser UI.
- Chrome 71 Released on 2018-12-04
- Chrome Android 71 Released on 2018-12-04
- Edge 79 Released on 2020-01-15
- Firefox 64 Released on 2018-12-11
- Firefox for Android 64 Released on 2018-12-11
- Safari 16.4 Released on 2023-03-27
- Safari on iOS Not supported
Baseline availability blocked since March 2023 by Safari (40 months)
-
Gamepad touch buttons
Limited availabilityThe
touchedproperty of aGamepadButtonobject indicates whether a button capable of detecting touch is currently touched.- Chrome 73 Released on 2019-03-12
- Chrome Android 73 Released on 2019-03-12
- Edge 15 Released on 2017-04-05
- Firefox 55 Released on 2017-08-08
- Firefox for Android 55 Released on 2017-08-08
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since March 2019 by Safari (88 months)
-
Custom highlights from point
Limited availabilityThe
CSS.highlights.highlightsFromPoint()method returns an array ofHighlightobjects at a specified point.- Chrome 140 Released on 2025-09-02
- Chrome Android 140 Released on 2025-09-02
- Edge 140 Released on 2025-09-05
- Firefox 150 Released on 2026-04-21
- Firefox for Android 150 Released on 2026-04-21
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2026 by Safari (3 months)
-
Hyphenate limit chars
Limited availabilityThe
hyphenate-limit-charsCSS property sets the number of characters in a word before it is hyphenated and the minimum number of characters on either side of the hyphen.- Chrome 109 Released on 2023-01-10
- Chrome Android 109 Released on 2023-01-10
- Edge 109 Released on 2023-01-12
- Firefox 137 Released on 2025-04-01
- Firefox for Android 137 Released on 2025-04-01
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2025 by Safari (15 months)
-
Error.isError()
Limited availabilityThe
Error.isError()static method checks whether a value is anErrorobject.- Chrome 134 Released on 2025-03-04
- Chrome Android 134 Released on 2025-03-04
- Edge 134 Released on 2025-03-06
- Firefox 138 Released on 2025-04-29
- Firefox for Android 138 Released on 2025-04-29
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2025 by Safari (15 months)
-
<link rel="prefetch">
Limited availabilityThe
rel="prefetch"attribute for the<link>HTML element is a hint to the browser that the user is likely to navigate to a resource, so the browser should preemptively fetch and cache the resource.- Chrome 8 Released on 2010-12-02
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 2 Released on 2006-10-24
- Firefox for Android 4 Released on 2011-03-29
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2015 by Safari (132 months)
-
::marker
Limited availabilityThe
::markerCSS pseudo-element selects list item markers for styling numbers or bullets.- Chrome 86 Released on 2020-10-20
- Chrome Android 86 Released on 2020-10-20
- Edge 86 Released on 2020-10-09
- Firefox 80 Released on 2020-08-25
- Firefox for Android 80 Released on 2020-08-31
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since October 2020 by Safari (69 months)
-
Media source
Limited availabilityThe
MediaSourceAPI is a custom data source for media elements commonly used for adaptive streaming. Also known as Media Source Extensions (MSE).- Chrome 31 Released on 2013-11-12
- Chrome Android 31 Released on 2013-11-14
- Edge 12 Released on 2015-07-29
- Firefox 42 Released on 2015-11-03
- Firefox for Android 41 Released on 2015-09-22
- Safari 8 Released on 2014-10-16
- Safari on iOS Not supported
Baseline availability blocked since November 2015 by Safari (128 months)
-
moveBefore()
Limited availabilityThe
moveBefore()DOM method relocates a node while preserving its state. For example, you can move the active element without losing focus, move an animated element without resetting the animation, or move an iframe without reloading its content.- Chrome 133 Released on 2025-02-04
- Chrome Android 133 Released on 2025-02-04
- Edge 133 Released on 2025-02-06
- Firefox 144 Released on 2025-10-14
- Firefox for Android 144 Released on 2025-10-14
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since October 2025 by Safari (9 months)
-
overflow-anchor
Limited availabilityThe
overflow-anchorCSS property sets an element as a possible scroll anchor, reducing unintended scrolling when document changes occur above the current scrollport. This is enabled by default where supported.- Chrome 56 Released on 2017-01-25
- Chrome Android 56 Released on 2017-02-01
- Edge 79 Released on 2020-01-15
- Firefox 66 Released on 2019-03-19
- Firefox for Android 66 Released on 2019-03-19
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2020 by Safari (78 months)
-
overscroll-behavior
Limited availabilityThe
overscroll-behaviorCSS property disables default scrolling behaviors when the edges of a scrolling area are reached.- Chrome 144 Released on 2026-01-13
- Chrome Android 144 Released on 2026-01-13
- Edge 144 Released on 2026-01-21
- Firefox 150 Released on 2026-04-21
- Firefox for Android 150 Released on 2026-04-21
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2026 by Safari (3 months)
-
page-orientation
Limited availabilityThe
page-orientationCSS property sets the rotation of a page after pagination. This allows pages with the samesizedeclaration to display with different orientations.- Chrome 85 Released on 2020-08-25
- Chrome Android 85 Released on 2020-08-25
- Edge 85 Released on 2020-08-27
- Firefox 122 Released on 2024-01-23
- Firefox for Android 122 Released on 2024-01-23
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2024 by Safari (30 months)
-
popover="hint"
Limited availabilityThe
popover="hint"global HTML attribute creates a popover that is subordinate to popovers with apopover="auto"attribute. You can use this to create tooltips that don't dismissautopopovers.- Chrome 133 Released on 2025-02-04
- Chrome Android 133 Released on 2025-02-04
- Edge 133 Released on 2025-02-06
- Firefox 149 Released on 2026-03-24
- Firefox for Android 149 Released on 2026-03-24
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since March 2026 by Safari (4 months)
-
Crash reporting
Limited availabilityCrash reporting sends a report to a URL nominated by the
Reporting-Endpointsheader when a user is unable to continue using the page because the browser or tab crashed.- Chrome 96 Released on 2021-11-15
- Chrome Android 96 Released on 2021-11-15
- Edge 96 Released on 2021-11-19
- Firefox 149 Released on 2026-03-24
- Firefox for Android 149 Released on 2026-03-24
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since March 2026 by Safari (4 months)
-
requestIdleCallback()
Limited availabilityThe
requestIdleCallback()API queues a function that runs in idle browser time, either at the end of a frame or when the user is inactive. Also known as the background tasks API.- Chrome 47 Released on 2015-12-01
- Chrome Android 47 Released on 2015-12-02
- Edge 79 Released on 2020-01-15
- Firefox 55 Released on 2017-08-08
- Firefox for Android 55 Released on 2017-08-08
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2020 by Safari (78 months)
-
Scheduler API
Limited availabilityThe
schedulerAPI provides a way to prioritize all tasks belonging to an application.- Chrome 129 Released on 2024-09-17
- Chrome Android 129 Released on 2024-09-17
- Edge 129 Released on 2024-09-19
- Firefox 142 Released on 2025-08-19
- Firefox for Android 142 Released on 2025-08-19
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since August 2025 by Safari (11 months)
-
::selection
Limited availabilityThe
::selectionCSS pseudo-element selects text a user has highlighted.- Chrome 1 Released on 2008-12-11
- Chrome Android 18 Released on 2012-06-27
- Edge 12 Released on 2015-07-29
- Firefox 62 Released on 2018-09-05
- Firefox for Android 62 Released on 2018-09-05
- Safari 1.1 Released on 2003-10-24
- Safari on iOS Not supported
Baseline availability blocked since September 2018 by Safari (94 months)
-
Serializable errors
Limited availabilityThe
DOMException,Error,EvalError,RangeError,ReferenceError,SyntaxError,TypeError, andURIErrorobjects are serializable. You can callstructuredClone()on an error object or pass it to a worker usingpostMessage().- Chrome 77 Released on 2019-09-10
- Chrome Android 77 Released on 2019-09-10
- Edge 79 Released on 2020-01-15
- Firefox 103 Released on 2022-07-26
- Firefox for Android 103 Released on 2022-07-26
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2022 by Safari (48 months)
-
showPicker() for <input>
Limited availabilityThe
showPicker()method for<input>elements shows the user interface for picking a value. For example, for<input type="date">it shows the interface for picking a date.- Chrome 99 Released on 2022-03-01
- Chrome Android 99 Released on 2022-03-01
- Edge 99 Released on 2022-03-03
- Firefox 101 Released on 2022-05-31
- Firefox for Android 101 Released on 2022-05-31
- Safari 17.4 Released on 2024-03-05
- Safari on iOS Not supported
Baseline availability blocked since March 2024 by Safari (28 months)
-
showPicker() for <select>
Limited availabilityThe
showPicker()method for<select>elements shows the dropdown menu or other user interface for picking one of the options.- Chrome 121 Released on 2024-01-23
- Chrome Android 121 Released on 2024-01-23
- Edge 121 Released on 2024-01-25
- Firefox 122 Released on 2024-01-23
- Firefox for Android 122 Released on 2024-01-23
- Safari Not supported Position: support
- Safari on iOS Not supported Position: support
Baseline availability blocked since January 2024 by Safari (30 months)
-
<img sizes="auto" loading="lazy">
Limited availabilityThe
sizes="auto"attribute for the<img>HTML element sets the layout size for the image based on the computed layout size when choosing a source from thesrcset. This attribute only applies to images with theloading="lazy"attribute.- Chrome 126 Released on 2024-06-11
- Chrome Android 126 Released on 2024-06-11
- Edge 126 Released on 2024-06-13
- Firefox 150 Released on 2026-04-21
- Firefox for Android 150 Released on 2026-04-21
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2026 by Safari (3 months)
-
Temporal
Limited availabilityThe
TemporalAPI allows you to work with dates, times, time zones, and durations. It is more powerful than theDateAPI.- Chrome 144 Released on 2026-01-13
- Chrome Android 144 Released on 2026-01-13
- Edge 144 Released on 2026-01-21
- Firefox 139 Released on 2025-05-27
- Firefox for Android 139 Released on 2025-05-27
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2026 by Safari (6 months)
-
text-justify
Limited availabilityThe
text-justifyCSS property sets the justification method of text whentext-align: justifyis set.- Chrome 145 Released on 2026-02-10
- Chrome Android 145 Released on 2026-02-10
- Edge 145 Released on 2026-02-14
- Firefox 55 Released on 2017-08-08
- Firefox for Android 55 Released on 2017-08-08
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since February 2026 by Safari (5 months)
-
Top-level await
Limited availabilityThe
awaitkeyword, when used at the top level of a module (outside of an async function), delays parent module execution until after a promise fulfills.- Chrome 89 Released on 2021-03-02
- Chrome Android 89 Released on 2021-03-02
- Edge 89 Released on 2021-03-04
- Firefox 89 Released on 2021-06-01
- Firefox for Android 89 Released on 2021-06-01
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since June 2021 by Safari (61 months)
-
Touch events
Limited availabilityTouch events
touchstart,touchmove,touchend, andtouchcancelfire when users interact with a touch-sensitive surface, such as a screen or drawing tablet. These events are similar to mouse events.- Chrome 22 Released on 2012-09-25
- Chrome Android 25 Released on 2013-02-27
- Edge 12 Released on 2015-07-29
- Firefox 52 Released on 2017-03-07
- Firefox for Android 6 Released on 2011-08-16
- Safari Not supported
- Safari on iOS ≤3 Released before 2009-06-17
Baseline availability blocked since March 2017 by Safari (112 months)
-
Transferable streams
Limited availabilityStreams are transferable objects, which can be moved between contexts such as windows and workers.
- Chrome 87 Released on 2020-11-17
- Chrome Android 87 Released on 2020-11-17
- Edge 87 Released on 2020-11-19
- Firefox 103 Released on 2022-07-26
- Firefox for Android 103 Released on 2022-07-26
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2022 by Safari (48 months)
-
user-select
Limited availabilityThe
user-selectCSS property controls which elements can be selected by the user.- Chrome 54 Released on 2016-10-12
- Chrome Android 54 Released on 2016-10-19
- Edge 79 Released on 2020-01-15
- Firefox 69 Released on 2019-09-03
- Firefox for Android 79 Released on 2020-07-28
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2020 by Safari (72 months)
-
Memory64 (WebAssembly)
Limited availabilityInstructions accept 64-bit memory indexes.
- Chrome 133 Released on 2025-02-04
- Chrome Android 133 Released on 2025-02-04
- Edge 133 Released on 2025-02-06
- Firefox 134 Released on 2025-01-07
- Firefox for Android 134 Released on 2025-01-07
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since February 2025 by Safari (17 months)
-
Multi-memory (WebAssembly)
Limited availabilityA single module in WebAssembly can have multiple memories.
- Chrome 120 Released on 2023-12-05
- Chrome Android 120 Released on 2023-12-05
- Edge 120 Released on 2023-12-07
- Firefox 125 Released on 2024-04-16
- Firefox for Android 125 Released on 2024-04-16
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since April 2024 by Safari (27 months)
-
Relaxed-width SIMD (WebAssembly)
Limited availabilityRelaxed SIMD (Single Instruction Multiple Data) introduces local non-determinism, where the results of the instructions may vary based on hardware support.
- Chrome 114 Released on 2023-05-30
- Chrome Android 114 Released on 2023-05-30
- Edge 114 Released on 2023-06-02
- Firefox 146 Released on 2025-12-09
- Firefox for Android 146 Released on 2025-12-09
- Safari Not supported Position: neutral
- Safari on iOS Not supported Position: neutral
Baseline availability blocked since December 2025 by Safari (7 months)
-
String builtins (WebAssembly)
Limited availabilityThe WebAssembly builtin string functions mirror a subset of the JavaScript
StringAPI and adapt it to be efficiently callable without JavaScript glue code.- Chrome 130 Released on 2024-10-15
- Chrome Android 130 Released on 2024-10-15
- Edge 130 Released on 2024-10-17
- Firefox 134 Released on 2025-01-07
- Firefox for Android 134 Released on 2025-01-07
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since January 2025 by Safari (18 months)
-
WebDriver BiDi
Limited availabilityWebDriver BiDi is a bidirectional protocol that allows a WebDriver client and a browser to communicate with each other.
- Chrome 106 Released on 2022-09-27
- Chrome Android 106 Released on 2022-09-27
- Edge 106 Released on 2022-10-03
- Firefox 102 Released on 2022-06-28
- Firefox for Android 102 Released on 2022-06-28
- Safari Not supported Position: support
- Safari on iOS Not supported Position: support
Baseline availability blocked since October 2022 by Safari (45 months)
-
SharedArrayBuffer in WebGL
Limited availabilitySharedArrayBufferobjects can be used in WebGL APIs that previously only worked withArrayBufferobjects.- Chrome 60 Released on 2017-07-25
- Chrome Android 60 Released on 2017-08-01
- Edge 79 Released on 2020-01-15
- Firefox 79 Released on 2020-07-28
- Firefox for Android 79 Released on 2020-07-28
- Safari Not supported
- Safari on iOS Not supported
Baseline availability blocked since July 2020 by Safari (72 months)
-
Wheel events
Limited availabilityThe
wheelevent fires when the user moves a mouse wheel or similar spatially rotating input device.- Chrome 31 Released on 2013-11-12
- Chrome Android 31 Released on 2013-11-14
- Edge 12 Released on 2015-07-29
- Firefox 17 Released on 2012-11-20
- Firefox for Android 17 Released on 2012-11-20
- Safari 7 Released on 2013-10-22
- Safari on iOS Not supported
Baseline availability blocked since July 2015 by Safari (132 months)