SpeechSynthesisEvent

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2018.

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.

Event SpeechSynthesisEvent

Constructor

SpeechSynthesisEvent()

Creates a new SpeechSynthesisEvent.

Instance 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.charLength Read only

Returns the number of characters left to be spoken after the charIndex position, if the speaking engine supports it. Returns 0 if the speaking engine can't provide the information.

SpeechSynthesisEvent.elapsedTime Read only

Returns the elapsed time in seconds 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 occurring 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.

Instance methods

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

Examples

js
utterThis.onpause = (event) => {
  const char = event.utterance.text.charAt(event.charIndex);
  console.log(
    `Speech paused at character ${event.charIndex} of "${event.utterance.text}", which is "${char}".`,
  );
};

utterThis.onboundary = (event) => {
  console.log(
    `${event.name} boundary reached after ${event.elapsedTime} seconds.`,
  );
};

Specifications

Specification
Web Speech API
# speechsynthesisevent

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
SpeechSynthesisEvent
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – Full support
Safari 7 (Release date: 2013-10-22)
footnote Full support
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 7 (Release date: 2013-09-18)
footnote Full support
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote
footnote See bug 40417848
WebView on iOS – Full support
WebView on iOS 7 (Release date: 2013-09-18)
footnote Full support
SpeechSynthesisEvent() constructor
Chrome – Full support
Chrome 71 (Release date: 2018-12-04)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 58 (Release date: 2019-01-23)
footnote Full support
Safari – Full support
Safari 16 (Release date: 2022-09-12)
footnote Full support
Chrome Android – Full support
Chrome Android 71 (Release date: 2018-12-04)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 16 (Release date: 2022-09-12)
footnote Full support
Samsung Internet – Full support
Samsung Internet 10 (Release date: 2019-08-22)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 16 (Release date: 2022-09-12)
footnote Full support
charIndex
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – Full support
Safari 7 (Release date: 2013-10-22)
footnote Full support
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 7 (Release date: 2013-09-18)
footnote Full support
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 7 (Release date: 2013-09-18)
footnote Full support
charLength
Chrome – Full support
Chrome 77 (Release date: 2019-09-10)
footnote Full support
Edge – Full support
Edge 15 (Release date: 2017-04-05)
footnote Full support
Firefox – Full support
Firefox 53 (Release date: 2017-04-19)
footnote Full support
Opera – Full support
Opera 64 (Release date: 2019-10-07)
footnote Full support
Safari – Full support
Safari 16 (Release date: 2022-09-12)
footnote Full support
Chrome Android – Full support
Chrome Android 77 (Release date: 2019-09-10)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 16 (Release date: 2022-09-12)
footnote Full support
Samsung Internet – Full support
Samsung Internet 12 (Release date: 2020-06-19)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 16 (Release date: 2022-09-12)
footnote Full support
elapsedTime
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – Full support
Safari 7 (Release date: 2013-10-22)
footnote Full support
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 7 (Release date: 2013-09-18)
footnote Full support
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 7 (Release date: 2013-09-18)
footnote Full support
elapsedTime in milliseconds
Deprecated Non-standard
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Partial support
Firefox 49 – 94 (Release date: 2016-09-20)
footnote Removed in 95 and later
footnote Partial support
footnote Windows and macOS only.
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – No support
Safari 7 – 14 (Release date: 2013-10-22)
footnote Removed in 14.1 and later
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – No support
Safari on iOS 7 – 14 (Release date: 2013-09-18)
footnote Removed in 14.5 and later
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – No support
WebView on iOS 7 – 14 (Release date: 2013-09-18)
footnote Removed in 14.5 and later
name
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – Full support
Safari 7 (Release date: 2013-10-22)
footnote Full support
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 7 (Release date: 2013-09-18)
footnote Full support
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 7 (Release date: 2013-09-18)
footnote Full support
utterance
Chrome – Full support
Chrome 33 (Release date: 2014-02-20)
footnote Full support
Edge – Full support
Edge 14 (Release date: 2016-08-02)
footnote Full support
Firefox – Full support
Firefox 49 (Release date: 2016-09-20)
footnote Full support
Opera – Full support
Opera 21 (Release date: 2014-05-06)
footnote Full support
Safari – Full support
Safari 16 (Release date: 2022-09-12)
footnote Full support
Chrome Android – Full support
Chrome Android 33 (Release date: 2014-02-26)
footnote Full support
Firefox for Android – Full support
Firefox for Android 62 (Release date: 2018-09-05)
footnote Full support
Opera Android – No support
Opera Android
footnote No support
Safari on iOS – Full support
Safari on iOS 16 (Release date: 2022-09-12)
footnote Full support
Samsung Internet – Full support
Samsung Internet 3 (Release date: 2015-04-10)
footnote Full support
WebView Android – No support
WebView Android
footnote No support
WebView on iOS – Full support
WebView on iOS 16 (Release date: 2022-09-12)
footnote Full support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
Partial support
Partial support
No support
No support
Non-standard. Check cross-browser support before using.
Deprecated. Not for use in new websites.
See implementation notes.

See also