Experimental

For a given set of browsers what APIs are still considred experimental, and how long have they been experimental?

Browsers
Features

Summary

Experimental APIs

Below is a list of features that are marked as "Experimental" in Firefox and Safari

Raw Data

Quick Links:

DOM API Data

API First Browser Date Last Browser Date Days in experimentation
api.AudioSession 📋Safari3/27/2023 402
api.AudioSession.type 📋Safari3/27/2023 402
api.BufferedChangeEvent 📋Safari9/18/2023 227
api.BufferedChangeEvent.BufferedChangeEvent 📋Safari9/18/2023 227
api.BufferedChangeEvent.addedRanges 📋Safari9/18/2023 227
api.BufferedChangeEvent.removedRanges 📋Safari9/18/2023 227
api.CSSPseudoElement 📋Firefox4/7/2020 1486
api.CSSPseudoElement.element 📋Firefox4/7/2020 1486
api.CSSPseudoElement.type 📋Firefox4/7/2020 1486
api.CaretPosition 📋Firefox4/2/2013 4048
api.CaretPosition.getClientRect 📋Firefox8/6/2013 3922
api.CaretPosition.offset 📋Firefox4/2/2013 4048
api.CaretPosition.offsetNode 📋Firefox4/2/2013 4048
api.ContentVisibilityAutoStateChangeEvent 📋Firefox2/14/2023 443
api.Credential.isConditionalMediationAvailable_static 📋Safari9/12/2022 598
api.CustomStateSet 📋Firefox12/19/2023 135
api.CustomStateSet.@@iterator 📋Firefox12/19/2023 135
api.CustomStateSet.add 📋Firefox12/19/2023 135
api.CustomStateSet.clear 📋Firefox12/19/2023 135
api.CustomStateSet.delete 📋Firefox12/19/2023 135
api.CustomStateSet.entries 📋Firefox12/19/2023 135
api.CustomStateSet.forEach 📋Firefox12/19/2023 135
api.CustomStateSet.has 📋Firefox12/19/2023 135
api.CustomStateSet.keys 📋Firefox12/19/2023 135
api.CustomStateSet.size 📋Firefox12/19/2023 135
api.CustomStateSet.values 📋Firefox12/19/2023 135
api.DataCue 📋Safari9/19/2017 2417
api.DataCue.DataCue 📋Safari9/19/2017 2417
api.DataCue.type 📋Safari9/19/2017 2417
api.DataCue.value 📋Safari9/19/2017 2417
api.DataTransfer.addElement Firefox6/30/2009 5420
api.DataTransfer.mozCursor Firefox6/30/2009 5420
api.DataTransfer.mozSourceNode Firefox3/22/2011 4790
api.DataTransfer.mozUserCancelled Firefox6/30/2009 5420
api.Directory Firefox1/7/2020 1577
api.Directory.getFiles Firefox1/7/2020 1577
api.Directory.getFilesAndDirectories Firefox1/7/2020 1577
api.Directory.name Firefox1/7/2020 1577
api.Directory.path Firefox1/7/2020 1577
api.Document.featurePolicy Firefox9/3/2019 1703
api.Document.getBoxQuads 📋Firefox7/22/2014 3572
api.Element.animate.options_iterationComposite_parameter 📋Firefox8/25/2020 1346
api.Element.ariaActiveDescendantElement 📋Safari3/27/2023 402
api.Element.ariaColIndexText 📋Firefox10/24/2023 191
api.Element.ariaControlsElements 📋Safari3/27/2023 402
api.Element.ariaDescribedByElements 📋Safari3/27/2023 402
api.Element.ariaDetailsElements 📋Safari3/27/2023 402
api.Element.ariaErrorMessageElements 📋Safari3/27/2023 402
api.Element.ariaFlowToElements 📋Safari3/27/2023 402
api.Element.ariaLabelledByElements 📋Safari3/27/2023 402
api.Element.ariaOwnsElements 📋Safari3/27/2023 402
api.Element.ariaRowIndexText 📋Firefox10/24/2023 191
api.Element.contentvisibilityautostatechange_event 📋Firefox2/14/2023 443
api.Element.getBoxQuads 📋Firefox7/22/2014 3572
api.Element.setHTML 📋Firefox11/2/2021 912
api.ElementInternals.ariaActiveDescendantElement 📋Safari3/27/2023 402
api.ElementInternals.ariaColIndexText 📋Firefox10/24/2023 191
api.ElementInternals.ariaControlsElements 📋Safari3/27/2023 402
api.ElementInternals.ariaDescribedByElements 📋Safari3/27/2023 402
api.ElementInternals.ariaDetailsElements 📋Safari3/27/2023 402
api.ElementInternals.ariaErrorMessageElements 📋Safari3/27/2023 402
api.ElementInternals.ariaFlowToElements 📋Safari3/27/2023 402
api.ElementInternals.ariaLabelledByElements 📋Safari3/27/2023 402
api.ElementInternals.ariaOwnsElements 📋Safari3/27/2023 402
api.ElementInternals.ariaRowIndexText 📋Firefox10/24/2023 191
api.ElementInternals.states 📋Firefox12/19/2023 135
api.FeaturePolicy Firefox1/29/2019 1920
api.FeaturePolicy.allowedFeatures Firefox1/29/2019 1920
api.FeaturePolicy.allowsFeature Firefox1/29/2019 1920
api.FeaturePolicy.features Firefox10/22/2019 1654
api.FeaturePolicy.getAllowlistForFeature Firefox1/29/2019 1920
api.FetchEvent.respondWith.resource_url Firefox3/13/2018 2242
api.FontFace.variationSettings 📋Firefox9/5/2018 2066
api.Gamepad.hand 📋Firefox8/8/2017 2459
api.Gamepad.hapticActuators 📋Firefox8/8/2017 2459
api.Gamepad.pose 📋Firefox8/8/2017 2459
api.Gamepad.secure_context_required Firefox8/10/2021 996
api.GamepadButton.secure_context_required Firefox8/10/2021 996
api.GamepadEvent.secure_context_required Firefox8/10/2021 996
api.GamepadHapticActuator.canPlayEffectType 📋Safari3/27/2023 402
api.GamepadPose 📋Firefox8/8/2017 2459
api.GamepadPose.angularAcceleration 📋Firefox8/8/2017 2459
api.GamepadPose.angularVelocity 📋Firefox8/8/2017 2459
api.GamepadPose.hasOrientation 📋Firefox8/8/2017 2459
api.GamepadPose.hasPosition 📋Firefox8/8/2017 2459
api.GamepadPose.linearAcceleration 📋Firefox8/8/2017 2459
api.GamepadPose.linearVelocity 📋Firefox8/8/2017 2459
api.GamepadPose.orientation 📋Firefox8/8/2017 2459
api.GamepadPose.position 📋Firefox8/8/2017 2459
api.GamepadPose.secure_context_required Firefox8/10/2021 996
api.HTMLAnchorElement.attributionSourceId 📋Safari3/14/2022 780
api.HTMLElement.focus.options_focusVisible_parameter Firefox8/23/2022 618
api.HTMLIFrameElement.featurePolicy Firefox9/3/2019 1703
api.HTMLInputElement.selectionchange_event 📋Firefox9/7/2021 968
api.HTMLOutputElement.HTMLOutputElement 📋Safari9/20/2021 955
api.HTMLTextAreaElement.selectionchange_event 📋Firefox9/7/2021 968
api.ImageCapture 📋Firefox1/13/2015 3397
api.ImageCapture.ImageCapture 📋Firefox1/13/2015 3397
api.ImageCapture.takePhoto 📋Firefox1/13/2015 3397
api.ImageCapture.track 📋Firefox1/13/2015 3397
api.InputEvent.inputType.insertFromPasteAsQuotation Firefox5/21/2019 1808
api.IntersectionObserverEntry.IntersectionObserverEntry Safari3/25/2019 1865
api.ManagedMediaSource 📋Safari9/18/2023 227
api.ManagedMediaSource.ManagedMediaSource 📋Safari9/18/2023 227
api.ManagedMediaSource.endstreaming_event 📋Safari9/18/2023 227
api.ManagedMediaSource.startstreaming_event 📋Safari9/18/2023 227
api.ManagedMediaSource.streaming 📋Safari9/18/2023 227
api.ManagedSourceBuffer 📋Safari9/18/2023 227
api.ManagedSourceBuffer.bufferedchange_event 📋Safari9/18/2023 227
api.MediaDevices.selectAudioOutput 📋Firefox8/1/2023 275
api.Navigator.audioSession 📋Safari3/27/2023 402
api.Navigator.getAutoplayPolicy 📋Firefox4/11/2023 387
api.Navigator.getGamepads.secure_context_required Firefox8/10/2021 996
api.Navigator.globalPrivacyControl Firefox11/21/2023 163
api.Navigator.registerProtocolHandler.scheme_parameter_ftp Firefox3/8/2022 786
api.Navigator.registerProtocolHandler.scheme_parameter_ftps Firefox3/8/2022 786
api.Navigator.registerProtocolHandler.scheme_parameter_sftp Firefox3/8/2022 786
api.PublicKeyCredential.parseCreationOptionsFromJSON_static 📋Firefox10/24/2023 191
api.PublicKeyCredential.parseRequestOptionsFromJSON_static 📋Firefox10/24/2023 191
api.PublicKeyCredential.toJSON 📋Firefox10/24/2023 191
api.PushSubscriptionChangeEvent.PushSubscriptionChangeEvent 📋Safari10/24/2022 556
api.RTCDataChannel.priority 📋Safari9/20/2021 955
api.RTCIdentityAssertion 📋Firefox8/11/2015 3187
api.RTCIdentityAssertion.idp 📋Firefox8/11/2015 3187
api.RTCIdentityAssertion.name 📋Firefox8/11/2015 3187
api.RTCStatsReport.type_remote-inbound-rtp.packetsReceived 📋Firefox1/7/2020 1577
api.ReadableStream.@@asyncIterator 📋Firefox2/14/2023 443
api.ReadableStream.from_static 📋Firefox8/29/2023 247
api.ReadableStream.values 📋Firefox2/14/2023 443
api.ReadableStreamBYOBReader.releaseLock.reject_pending_read_request Firefox6/28/2022 674
api.ReadableStreamDefaultReader.releaseLock.reject_pending_read_request Firefox6/28/2022 674
api.Request.cache.only-if-cached Firefox11/15/2016 2725
api.SVGScriptElement.async Firefox8/29/2023 247
api.SVGScriptElement.defer Firefox8/29/2023 247
api.Sanitizer 📋Firefox11/17/2020 1262
api.Sanitizer.Sanitizer 📋Firefox11/17/2020 1262
api.Sanitizer.sanitize 📋Firefox11/17/2020 1262
api.Selection.direction 📋Safari9/18/2023 227
api.Selection.getComposedRanges 📋Safari9/18/2023 227
api.SourceBuffer.appendBufferAsync Firefox9/5/2018 2066
api.SourceBuffer.removeAsync Firefox9/5/2018 2066
api.SourceBuffer.textTracks 📋Safari10/16/2014 3486
api.SpeechGrammar 📋Firefox1/26/2016 3019
api.SpeechGrammar.SpeechGrammar Firefox1/26/2016 3019
api.SpeechGrammar.src 📋Firefox1/26/2016 3019
api.SpeechGrammar.weight 📋Firefox1/26/2016 3019
api.SpeechRecognitionErrorEvent.SpeechRecognitionErrorEvent 📋Safari4/26/2021 1102
api.SpeechRecognitionEvent.SpeechRecognitionEvent 📋Safari4/26/2021 1102
api.Text.getBoxQuads 📋Firefox7/22/2014 3572
api.WebGLActiveInfo.worker_support Firefox9/20/2022 590
api.WebGLBuffer.worker_support Firefox9/20/2022 590
api.WebGLContextEvent.worker_support Firefox9/20/2022 590
api.WebGLFramebuffer.worker_support Firefox9/20/2022 590
api.WebGLProgram.worker_support Firefox9/20/2022 590
api.WebGLRenderbuffer.worker_support Firefox9/20/2022 590
api.WebGLRenderingContext.worker_support Firefox9/20/2022 590
api.WebGLShader.worker_support Firefox9/20/2022 590
api.WebGLShaderPrecisionFormat.worker_support Firefox9/20/2022 590
api.WebGLTexture.worker_support Firefox9/20/2022 590
api.WebGLUniformLocation.worker_support Firefox9/20/2022 590
api.WebTransport.WebTransport.options_allowPooling_parameter 📋Firefox6/6/2023 331
api.WebTransport.WebTransport.options_congestionControl_parameter 📋Firefox6/6/2023 331
api.WebTransport.WebTransport.options_requireUnreliable_parameter 📋Firefox6/6/2023 331
api.WebTransport.congestionControl 📋Firefox6/6/2023 331
api.WebTransport.createBidirectionalStream.options_sendOrder_parameter 📋Firefox10/24/2023 191
api.WebTransport.createUnidirectionalStream.options_sendOrder_parameter 📋Firefox10/24/2023 191
api.WebTransport.getStats 📋Firefox6/6/2023 331
api.WebTransport.reliability 📋Firefox6/6/2023 331
api.WebTransportBidirectionalStream.readable.returns_WebTransportReceiveStream 📋Firefox6/6/2023 331
api.WebTransportBidirectionalStream.writable.returns_WebTransportSendStream 📋Firefox6/6/2023 331
api.WebTransportReceiveStream 📋Firefox6/6/2023 331
api.WebTransportReceiveStream.getStats 📋Firefox6/6/2023 331
api.WebTransportSendStream 📋Firefox6/6/2023 331
api.WebTransportSendStream.getStats 📋Firefox6/6/2023 331
api.WebTransportSendStream.sendOrder 📋Firefox12/19/2023 135
api.WindowClient.ancestorOrigins 📋Safari9/12/2022 598
api.WorkerNavigator.globalPrivacyControl Firefox11/21/2023 163

CSS Data

API First Browser Date Last Browser Date Days in experimentation
css.at-rules.media.prefers-reduced-transparency 📋Firefox5/9/2023 359
css.properties.-webkit-column-axis Safari3/24/2020 1500
css.properties.-webkit-column-progression Safari3/24/2020 1500
css.properties.-webkit-cursor-visibility Safari3/24/2020 1500
css.properties.-webkit-hyphenate-limit-after Safari3/24/2020 1500
css.properties.-webkit-hyphenate-limit-before Safari3/24/2020 1500
css.properties.-webkit-hyphenate-limit-lines Safari3/24/2020 1500
css.properties.-webkit-initial-letter Safari3/24/2020 1500
css.properties.-webkit-line-align Safari3/24/2020 1500
css.properties.-webkit-line-box-contain Safari3/24/2020 1500
css.properties.-webkit-line-clamp.none Firefox7/9/2019 1759
css.properties.-webkit-line-grid Safari3/24/2020 1500
css.properties.-webkit-line-snap Safari3/24/2020 1500
css.properties.-webkit-mask-source-type Safari3/24/2020 1500
css.properties.-webkit-nbsp-mode Safari3/24/2020 1500
css.properties.-webkit-text-decoration-skip Safari3/24/2020 1500
css.properties.-webkit-text-zoom Safari3/24/2020 1500
css.properties.align-tracks 📋Firefox6/2/2020 1430
css.properties.animation-timeline 📋Firefox2/14/2023 443
css.properties.animation-timeline.scroll 📋Firefox2/14/2023 443
css.properties.animation-timeline.view 📋Firefox6/6/2023 331
css.properties.background-image.element 📋Firefox3/22/2011 4790
css.properties.block-size.fit-content_function Firefox8/10/2021 996
css.properties.break-after.always Firefox1/7/2020 1577
css.properties.break-before.always Firefox1/7/2020 1577
css.properties.content.none_applies_to_elements Firefox8/10/2021 996
css.properties.counter-reset.reset_does_not_affect_siblings Firefox10/20/2020 1290
css.properties.counter-reset.reversed 📋Firefox1/11/2022 842
css.properties.grid-template-columns.masonry 📋Firefox6/2/2020 1430
css.properties.grid-template-rows.masonry 📋Firefox6/2/2020 1430
css.properties.height.fit-content_function Firefox8/10/2021 996
css.properties.image-rendering.smooth Firefox10/5/2021 940
css.properties.initial-letter 📋Safari9/30/2015 3137
css.properties.inline-size.fit-content_function Firefox8/10/2021 996
css.properties.justify-tracks 📋Firefox6/2/2020 1430
css.properties.margin-trim 📋Safari3/27/2023 402
css.properties.max-block-size.fit-content_function Firefox8/10/2021 996
css.properties.max-height.fit-content_function Firefox8/10/2021 996
css.properties.max-inline-size.fit-content_function Firefox8/10/2021 996
css.properties.max-width.fit-content_function Firefox8/10/2021 996
css.properties.min-block-size.fit-content_function Firefox8/10/2021 996
css.properties.min-height.fit-content_function Firefox8/10/2021 996
css.properties.min-height.stretch Safari9/30/2015 3137
css.properties.min-inline-size.fit-content_function Firefox8/10/2021 996
css.properties.min-width.fit-content_function Firefox8/10/2021 996
css.properties.ruby-align 📋Firefox5/12/2015 3278
css.properties.ruby-position.alternate Firefox4/19/2021 1109
css.properties.scroll-timeline 📋Firefox3/14/2023 415
css.properties.scroll-timeline-axis 📋Firefox3/14/2023 415
css.properties.scroll-timeline-name 📋Firefox3/14/2023 415
css.properties.speak-as 📋Safari4/12/2018 2212
css.properties.stroke-color 📋Safari3/24/2020 1500
css.properties.text-decoration-skip 📋Safari3/25/2019 1865
css.properties.text-wrap.stable 📋Firefox12/19/2023 135
css.properties.view-timeline 📋Firefox6/6/2023 331
css.properties.view-timeline-axis 📋Firefox6/6/2023 331
css.properties.view-timeline-name 📋Firefox3/14/2023 415
css.properties.width.fit-content_function Firefox8/10/2021 996
css.properties.width.stretch Firefox6/17/2008 Safari10/22/20131953
css.selectors.-moz-first-node Firefox1/7/2020 1577
css.selectors.-moz-focus-inner Firefox1/7/2020 1577
css.selectors.-moz-last-node Firefox1/7/2020 1577
css.selectors.-moz-list-bullet Firefox1/7/2020 1577
css.selectors.-moz-list-number Firefox1/7/2020 1577
css.selectors.-moz-progress-bar Firefox1/7/2020 1577
css.selectors.state 📋Firefox12/19/2023 135
css.types.attr.fallback Firefox10/24/2023 191
css.types.color.color-contrast 📋Safari9/20/2021 955
css.types.color.system-color.mark_marktext_buttonborder 📋Firefox1/17/2023 471
css.types.global_keywords.revert-layer 📋Firefox2/8/2022 814
css.types.image.element 📋Firefox11/14/2017 2361
css.types.ratio.number_value Firefox10/22/2019 1654

JS Data

API First Browser Date Last Browser Date Days in experimentation
javascript.builtins.AggregateError.serializable_object Firefox7/26/2022 646
javascript.builtins.Intl.DurationFormat 📋Safari3/27/2023 402
javascript.builtins.Intl.DurationFormat.DurationFormat 📋Safari3/27/2023 402
javascript.builtins.Intl.DurationFormat.format 📋Safari3/27/2023 402
javascript.builtins.Intl.DurationFormat.formatToParts 📋Safari3/27/2023 402
javascript.builtins.Intl.DurationFormat.resolvedOptions 📋Safari3/27/2023 402
javascript.builtins.Intl.DurationFormat.supportedLocalesOf 📋Safari3/27/2023 402
javascript.builtins.Intl.PluralRules.PluralRules.options_roundingIncrement_parameter Firefox8/1/2023 275
javascript.builtins.Intl.PluralRules.PluralRules.options_roundingMode_parameter Firefox8/1/2023 275
javascript.builtins.Intl.PluralRules.PluralRules.options_roundingPriority_parameter Firefox8/1/2023 275
javascript.builtins.Intl.PluralRules.PluralRules.options_trailingZeroDisplay_parameter Firefox8/1/2023 275