This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.

The error read-only property of the SpeechRecognitionError interface returns the type of error raised.


var myError = event.error;


A DOMString naming the type of error. The possible error types are:

No speech was detected.
Speech input was aborted in some manner, perhaps by some user-agent-specific behavior like a button the user can press to cancel speech input.
Audio capture failed.
Network communication required for completing the recognition failed.
The user agent disallowed any speech input from occurring for reasons of security, privacy or user preference.
The user agent disallowed the requested speech recognition service, either because the user agent doesn't support it or because of reasons of security, privacy or user preference. In this case it would allow another more suitable speech recognition service to be used instead.
There was an error in the speech recognition grammar or semantic tags, or the chosen grammar format or semantic tag format was unsupported.
The language was not supported.


var recognition = new SpeechRecognition();

recognition.onerror = function(event) {
  console.log('Speech recognition error detected: ' + event.error);
  console.log('Additional information: ' + event.message);


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

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 33 [1] 44 (44) [2] Not supported Not supported Not supported
Feature Android Chrome Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support ? (Yes)[1] ? 2.5 Not supported Not supported Not supported
  • [1] Speech recognition interfaces are currently prefixed on Chrome, so you'll need to prefix interface names appropriately, e.g. webkitSpeechRecognition; You'll also need to serve your code through a web server for recognition to work.
  • [2] Can be enabled via the media.webspeech.recognition.enable flag in about:config, although note that currently speech recognition won't work on Desktop Firefox — it will be properly exposed soon, once the required internal permissions are sorted out.

Firefox OS permissions

To use speech recognition in an app, you need to specify the following permissions in your manifest:

"permissions": {
  "audio-capture" : {
    "description" : "Audio capture"
  "speech-recognition" : {
    "description" : "Speech recognition"

You also need a privileged app, so you need to include this as well:

"type": "privileged"

See also


© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.

API Error Experimental Property recognition Reference speech SpeechRecognitionError Web Speech API