SpeechSynthesis.onvoiceschanged

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

The onvoiceschanged property of the SpeechSynthesis interface represents an event handler that will run when the list of SpeechSynthesisVoice objects that would be returned by the SpeechSynthesis.getVoices() method has changed (when the voiceschanged event fires.)

This may occur when speech synthesis is being done on the server-side and the voices list is being determined asynchronously, or when client-side voices are installed/uninstalled while a speech synthesis application is running.

Syntax

speechSynthesisInstance.onvoiceschanged = function() { ... };

Examples

This could be used to populate a list of voices that the user can choose between when the event fires (see our Speak easy synthesis demo.) Note that Firefox doesn't support it at present, and will just return a list of voices when SpeechSynthesis.getVoices() is fired. With Chrome however, you have to wait for the event to fire before populating the list, hence the bottom if statement seen below.

var synth = window.speechSynthesis;
var voices = [];

function populateVoiceList() {
  voices = synth.getVoices();

  for(i = 0; i < voices.length ; i++) {
    var option = document.createElement('option');
    option.textContent = voices[i].name + ' (' + voices[i].lang + ')';

    if(voices[i].default) {
      option.textContent += ' -- DEFAULT';
    }

    option.setAttribute('data-lang', voices[i].lang);
    option.setAttribute('data-name', voices[i].name);
    voiceSelect.appendChild(option);
  }
}

populateVoiceList();
if (speechSynthesis.onvoiceschanged !== undefined) {
  speechSynthesis.onvoiceschanged = populateVoiceList;
}

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
onvoiceschanged
33
14
49
No
No
No
No
33
62
No
No
3.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/SpeechSynthesis/onvoiceschanged