SpeechSynthesisEvent

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The SpeechSynthesisEvent interface of the Web Speech API contains information about the current state of SpeechSynthesisUtterance objects that have been processed in the speech service.

Properties

The SpeechSynthesisEvent interface also inherits properties from its parent interface, Event.

SpeechSynthesisEvent.charIndex Read only
Returns the index position of the character in the SpeechSynthesisUtterance.text that was being spoken when the event was triggered.
SpeechSynthesisEvent.elapsedTime Read only
Returns the elapsed time in milliseconds after the SpeechSynthesisUtterance.text started being spoken that the event was triggered at.
SpeechSynthesisEvent.name Read only
Returns the name associated with certain types of events occuring as the SpeechSynthesisUtterance.text is being spoken: the name of the SSML marker reached in the case of a mark event, or the type of boundary reached in the case of a boundary event.
SpeechSynthesisEvent.utterance Read only
Returns the SpeechSynthesisUtterance instance that the event was triggered on.

Methods

The SpeechSynthesisEvent interface also inherits methods from its parent interface, Event.

Examples

utterThis.onpause = function(event) {
  var char = event.utterance.text.charAt(event.charIndex);
  console.log('Speech paused at character ' + event.charIndex + ' of "' +
  event.utterance.text + '", which is "' + char + '".');
}

utterThis.onboundary = function(event) {
  console.log(event.name + ' boundary reached after ' + event.elapsedTime + ' milliseconds.');
}

Specifications

Specification Status Comment
Web Speech API
The definition of 'SpeechSynthesisEvent' in that specification.
Draft

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
SpeechSynthesisEvent
Experimental
Chrome Full support 33Edge Full support ≤18Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0
charIndex
Experimental
Chrome Full support 33Edge Full support 14Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0
elapsedTime
Experimental
Chrome Full support 33Edge Full support 14Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0
name
Experimental
Chrome Full support 33Edge Full support 14Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0
utterance
Experimental
Chrome Full support 33Edge Full support 14Firefox Full support 49IE No support NoOpera Full support 21Safari Full support 7WebView Android No support NoChrome Android Full support 33Firefox Android Full support 62
Full support 62
No support 61 — 62
Disabled
Disabled From version 61 until version 62 (exclusive): this feature is behind the media.webspeech.synth.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
Opera Android No support NoSafari iOS Full support 7Samsung Internet Android Full support 3.0

Legend

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.

See also