SpeechSynthesis.onvoiceschanged

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 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

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support33 Yes49 No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support3333 Yes

62

61 — 621

No No ?

1. 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.

See also

Document Tags and Contributors

Contributors to this page: lucian95, abbycar, tomayac, chrisdavidmills, dev.mnr.j
Last updated by: lucian95,