Not yet stable

For a given set of browsers, what APIs are not yet in all of them.

Example Comparisons
Browsers
Features

Summary

A count of the number of APIs are in Browser X but not in Browser Y.
Not in EdgeNot in Firefox
In Edge 108
In Firefox 19

Unstable APIs

Below is a list of features that are not in all of Edge and Firefox

Raw Data

Quick Links:

HTML Data

API First Browser Date Days in Limbo Notes
html.elements.a.attributionsrc 📋Edge5/17/2024671
html.elements.a.coords 📋Edge1/15/20202255
Firefox: You can no longer nest an <a> element inside a <map> element to create a hotspot region - coords and shape attribute support removed.Firefox for Android: You can no longer nest an <a> element inside a <map> element to create a hotspot region - coords and shape attribute support removed.
html.elements.a.href.href_sms Firefox4/24/20125077
html.elements.a.interestfor Edge10/31/2025139
html.elements.a.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.a.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.a.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.a.shape 📋Edge1/15/20202255
Firefox: You can no longer nest an <a> element inside a <map> element to create a hotspot region - coords and shape attribute support removed.Firefox for Android: You can no longer nest an <a> element inside a <map> element to create a hotspot region - coords and shape attribute support removed.
html.elements.a.target.unfencedTop Edge6/13/2024644
html.elements.area.attributionsrc 📋Edge5/17/2024671
html.elements.area.interestfor Edge10/31/2025139
html.elements.area.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.area.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.area.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.audio.controlslist 📋Edge1/15/20202255
html.elements.audio.disableremoteplayback 📋Edge1/25/2024784
html.elements.button.interestfor Edge10/31/2025139
html.elements.canvas.moz-opaque Firefox6/30/20096106
html.elements.datalist.input_type_color 📋Edge8/2/20163516
html.elements.datalist.input_type_date 📋Edge7/29/20153886
html.elements.datalist.input_type_time 📋Edge7/29/20153886
html.elements.fencedframe 📋Edge6/13/2024644
html.elements.fencedframe.allow 📋Edge6/13/2024644
html.elements.fencedframe.height 📋Edge6/13/2024644
html.elements.fencedframe.width 📋Edge6/13/2024644
html.elements.form.autocomplete.new-password Firefox5/21/20192494
html.elements.geolocation 📋Edge1/21/202657
html.elements.geolocation.autolocate 📋Edge1/21/202657
html.elements.geolocation.watch 📋Edge1/21/202657
html.elements.h1.no_ua_styles_in_article_aside_nav_section 📋Firefox6/24/2025268
html.elements.iframe.allow.accelerometer 📋Edge1/15/20202255
html.elements.iframe.allow.ambient-light-sensor 📋Edge1/15/20202255
html.elements.iframe.allow.attribution-reporting 📋Edge9/15/2023916
html.elements.iframe.allow.bluetooth 📋Edge8/5/20221322
html.elements.iframe.allow.browsing-topics Edge7/21/2023972
html.elements.iframe.allow.compute-pressure 📋Edge5/17/2024671
html.elements.iframe.allow.cross-origin-isolated 📋Edge11/19/20201946
html.elements.iframe.allow.gamepad 📋Firefox8/10/20211682
Firefox: The default allowlist is * instead of self (as required by the specification).Firefox for Android: The default allowlist is * instead of self (as required by the specification).
html.elements.iframe.allow.gyroscope 📋Edge1/15/20202255
html.elements.iframe.allow.hid 📋Edge3/4/20211841
html.elements.iframe.allow.identity-credentials-get 📋Edge2/9/20231134
html.elements.iframe.allow.idle-detection 📋Edge9/24/20211637
html.elements.iframe.allow.local-fonts 📋Edge6/23/20221365
html.elements.iframe.allow.magnetometer 📋Edge1/15/20202255
html.elements.iframe.allow.otp-credentials 📋Edge9/2/20211659
html.elements.iframe.allow.picture-in-picture 📋Edge1/15/20202255
html.elements.iframe.allow.publickey-credentials-create 📋Firefox2/20/2024758
html.elements.iframe.allow.serial 📋Edge3/4/20211841
html.elements.iframe.allow.speaker-selection 📋Firefox8/1/2023961
Firefox for Android: Not available due to a limitation in Android (see bug 1473346).
html.elements.iframe.allow.storage-access 📋Edge5/5/20231049
html.elements.iframe.allow.usb 📋Edge1/15/20202255
html.elements.iframe.allow.wildcards Edge12/5/20221200
html.elements.iframe.allow.window-management 📋Edge4/1/20221448
html.elements.iframe.allow.xr-spatial-tracking 📋Edge1/15/20202255
html.elements.iframe.allowpaymentrequest Edge1/15/20202255
html.elements.iframe.browsingtopics Edge6/13/2024644
html.elements.iframe.credentialless 📋Edge2/9/20231134
html.elements.iframe.csp 📋Edge1/15/20202255
html.elements.iframe.privateToken 📋Edge9/15/2023916
html.elements.iframe.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.iframe.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.iframe.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.iframe.sandbox.allow-top-navigation-to-custom-protocols 📋Firefox5/31/20221388
html.elements.img.attributionsrc 📋Edge5/17/2024671
html.elements.img.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.img.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.img.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.img.sizes.auto 📋Edge6/13/2024644
html.elements.input.type_color.accepts_css_colors 📋Firefox9/16/2025184
html.elements.input.type_color.list 📋Edge8/2/20163516
html.elements.input.type_date.list 📋Edge7/29/20153886
html.elements.input.type_month 📋Edge7/29/20153886
Safari: The input type is recognized, but there is no month-specific control. See bug 200416.
html.elements.input.type_password.insecure_login_handling Firefox3/7/20173299
html.elements.input.type_time.list 📋Edge7/29/20153886
html.elements.input.type_week 📋Edge7/29/20153886
html.elements.link.blocking 📋Edge9/1/20221295
html.elements.link.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.link.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.link.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.link.rel.alternate_stylesheet 📋Firefox6/17/20086484
html.elements.link.rel.compression-dictionary 📋Edge10/17/2024518
html.elements.link.rel.expect 📋Edge4/18/2024700
html.elements.link.rel.manifest 📋Edge1/15/20202255
html.elements.link.rel.modulepreload.as-json 📋Edge4/9/2026-21
html.elements.link.rel.modulepreload.as-style 📋Edge4/9/2026-21
html.elements.link.rel.preload.as-track Edge1/15/20202255
html.elements.link.rel.prerender Edge1/15/20202255
Chrome: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.Chrome Android: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.Edge: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.Quest Browser: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.Opera: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.Opera Android: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.WebView Android: Does not trigger prerendering. Triggers NoState Prefetch instead. See blog post.
html.elements.meta.name.application-title Edge3/6/2025378
html.elements.meta.name.theme-color 📋Edge1/15/20202255
Chrome: Chrome uses the color only on installed progressive web apps.Chrome: Chrome reports support, but does not actually use the color anywhere.Chrome Android: Chrome for Android does not use the color on devices with native dark mode enabled unless it's an installed progressive web app or a trusted web activity.Edge: Edge uses the color only on installed progressive web apps.Quest Browser: Chrome for Android does not use the color on devices with native dark mode enabled unless it's an installed progressive web app or a trusted web activity.
html.elements.script.attributionsrc 📋Edge5/17/2024671
html.elements.script.blocking 📋Edge9/1/20221295
html.elements.script.referrerpolicy.no-referrer-when-downgrade Edge1/15/20202255
html.elements.script.referrerpolicy.origin-when-cross-origin Edge1/15/20202255
html.elements.script.referrerpolicy.unsafe-url Edge1/15/20202255
html.elements.script.type.importmap.multiple_import_maps 📋Edge2/6/2025406
html.elements.script.type.speculationrules 📋Edge1/12/20231162
Chrome: Initial support included same-origin prerendering only.Chrome Android: Initial support included same-origin prerendering only.Edge: Initial support included same-origin prerendering only.Quest Browser: Initial support included same-origin prerendering only.Opera: Initial support included same-origin prerendering only.Opera Android: Initial support included same-origin prerendering only.Samsung Internet: Initial support included same-origin prerendering only.WebView Android: Initial support included same-origin prerendering only.
html.elements.script.type.speculationrules.eagerness 📋Edge1/25/2024784
Safari: Only conservative is supported for document rules (though moderate automatically falls back to conservative). Only eager and immediate is supported for list rules.Safari on iOS: Only conservative is supported for document rules (though moderate automatically falls back to conservative). Only eager and immediate is supported for list rules.
html.elements.script.type.speculationrules.expects_no_vary_search 📋Edge7/25/2024602
Chrome: Supported for prefetch only.Chrome Android: Supported for prefetch only.Edge: Supported for prefetch only.Opera: Supported for prefetch only.Opera Android: Supported for prefetch only.Samsung Internet: Supported for prefetch only.WebView Android: Supported for prefetch only.
html.elements.script.type.speculationrules.prefetch 📋Edge2/9/20231134
html.elements.script.type.speculationrules.prerender 📋Edge9/1/20221295
html.elements.script.type.speculationrules.referrer_policy 📋Edge3/13/20231102
html.elements.script.type.speculationrules.relative_to 📋Edge1/25/2024784
html.elements.script.type.speculationrules.requires 📋Edge2/9/20231134
html.elements.script.type.speculationrules.source_optional 📋Edge2/23/2024755
html.elements.script.type.speculationrules.tag 📋Edge5/1/2025322
html.elements.script.type.speculationrules.target_hint 📋Edge6/26/2025266
Chrome: Only "_blank" and "_self" are supported and only for prefetch.Chrome Android: Only "_blank" and "_self" are supported and only for prefetch.Edge: Only "_blank" and "_self" are supported and only for prefetch.Opera: Only "_blank" and "_self" are supported and only for prefetch.Opera Android: Only "_blank" and "_self" are supported and only for prefetch.WebView Android: Only "_blank" and "_self" are supported and only for prefetch.
html.elements.script.type.speculationrules.urls 📋Edge1/12/20231162
html.elements.script.type.speculationrules.where 📋Edge1/25/2024784
html.elements.selectedcontent 📋Edge4/4/2025349
html.elements.style.blocking 📋Edge9/1/20221295
html.elements.tbody.charoff Firefox11/9/20047800
Chrome: Since Chrome 1, the attribute can be set, but has no effect.Chrome Android: Since Chrome Android 18, the attribute can be set, but has no effect.Edge: Since Edge 79, the attribute can be set, but has no effect.Quest Browser: Since Quest Browser 5.0, the attribute can be set, but has no effect.Opera: Since Opera 15, the attribute can be set, but has no effect.Opera Android: Since Opera Android 14, the attribute can be set, but has no effect.Safari: Since Safari 3, the attribute can be set, but has no effect.Safari on iOS: Since Safari on iOS 2, the attribute can be set, but has no effect.Samsung Internet: Since Samsung Internet 1.0, the attribute can be set, but has no effect.WebView Android: Since WebView Android 4.4, the attribute can be set, but has no effect.WebView on iOS: Since WebView on iOS 2, the attribute can be set, but has no effect.
html.elements.td.charoff Firefox11/9/20047800
Chrome: Since Chrome 1, the attribute can be set, but has no effect.Chrome Android: Since Chrome Android 18, the attribute can be set, but has no effect.Edge: Since Edge 79, the attribute can be set, but has no effect.Quest Browser: Since Quest Browser 5.0, the attribute can be set, but has no effect.Opera: Since Opera 15, the attribute can be set, but has no effect.Opera Android: Since Opera Android 14, the attribute can be set, but has no effect.Safari: Since Safari 3, the attribute can be set, but has no effect.Safari on iOS: Since Safari on iOS 2, the attribute can be set, but has no effect.Samsung Internet: Since Samsung Internet 1.0, the attribute can be set, but has no effect.WebView Android: Since WebView Android 4.4, the attribute can be set, but has no effect.WebView on iOS: Since WebView on iOS 2, the attribute can be set, but has no effect.
html.elements.template.shadowrootserializable 📋Edge5/17/2024671
html.elements.textarea.autocomplete.new-password Firefox5/21/20192494
html.elements.textarea.autocomplete.webauthn 📋Edge12/5/20221200
html.elements.textarea.wrap.hard Edge7/29/20153886
html.elements.tfoot.charoff Firefox11/9/20047800
Chrome: Since Chrome 1, the attribute can be set, but has no effect.Chrome Android: Since Chrome Android 18, the attribute can be set, but has no effect.Edge: Since Edge 79, the attribute can be set, but has no effect.Quest Browser: Since Quest Browser 5.0, the attribute can be set, but has no effect.Opera: Since Opera 15, the attribute can be set, but has no effect.Opera Android: Since Opera Android 14, the attribute can be set, but has no effect.Safari: Since Safari 3, the attribute can be set, but has no effect.Safari on iOS: Since Safari on iOS 2, the attribute can be set, but has no effect.Samsung Internet: Since Samsung Internet 1.0, the attribute can be set, but has no effect.WebView Android: Since WebView Android 4.4, the attribute can be set, but has no effect.WebView on iOS: Since WebView on iOS 2, the attribute can be set, but has no effect.
html.elements.th.charoff Firefox11/9/20047800
Chrome: Since Chrome 1, the attribute can be set, but has no effect.Chrome Android: Since Chrome Android 18, the attribute can be set, but has no effect.Edge: Since Edge 79, the attribute can be set, but has no effect.Quest Browser: Since Quest Browser 5.0, the attribute can be set, but has no effect.Opera: Since Opera 15, the attribute can be set, but has no effect.Opera Android: Since Opera Android 14, the attribute can be set, but has no effect.Safari: Since Safari 3, the attribute can be set, but has no effect.Safari on iOS: Since Safari on iOS 2, the attribute can be set, but has no effect.Samsung Internet: Since Samsung Internet 1.0, the attribute can be set, but has no effect.WebView Android: Since WebView Android 4.4, the attribute can be set, but has no effect.WebView on iOS: Since WebView on iOS 2, the attribute can be set, but has no effect.
html.elements.th.rowspan.rowspan_zero Firefox8/8/20173145
html.elements.thead.charoff Firefox11/9/20047800
Chrome: Since Chrome 1, the attribute can be set, but has no effect.Chrome Android: Since Chrome Android 18, the attribute can be set, but has no effect.Edge: Since Edge 79, the attribute can be set, but has no effect.Quest Browser: Since Quest Browser 5.0, the attribute can be set, but has no effect.Opera: Since Opera 15, the attribute can be set, but has no effect.Opera Android: Since Opera Android 14, the attribute can be set, but has no effect.Safari: Since Safari 3, the attribute can be set, but has no effect.Safari on iOS: Since Safari on iOS 2, the attribute can be set, but has no effect.Samsung Internet: Since Samsung Internet 1.0, the attribute can be set, but has no effect.WebView Android: Since WebView Android 4.4, the attribute can be set, but has no effect.WebView on iOS: Since WebView on iOS 2, the attribute can be set, but has no effect.
html.elements.video.controlslist 📋Edge1/15/20202255
html.elements.video.disableremoteplayback 📋Edge1/25/2024784
html.elements.video.playsinline 📋Edge1/15/20202255
html.global_attributes.autocorrect 📋Firefox3/4/2025380
html.global_attributes.popover.hint 📋Edge2/6/2025406
html.global_attributes.virtualkeyboardpolicy 📋Edge9/24/20211637
html.global_attributes.writingsuggestions 📋Edge4/18/2024700