SpeechRecognition.maxAlternatives

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

The maxAlternatives property of the SpeechRecognition interface sets the maximum number of SpeechRecognitionAlternatives provided per SpeechRecognitionResult.

The default value is 1.

Syntax

var myMaxAlternativeNumber = mySpeechRecognition.maxAlternatives;
mySpeechRecognition.maxAlternatives = 2;

Value

A number representing the maximum returned alternatives for each result.

Examples

This code is excerpted from our Speech color changer example.

var grammar = '#JSGF V1.0; grammar colors; public <color> = aqua | azure | beige | bisque | black | blue | brown | chocolate | coral | crimson | cyan | fuchsia | ghostwhite | gold | goldenrod | gray | green | indigo | ivory | khaki | lavender | lime | linen | magenta | maroon | moccasin | navy | olive | orange | orchid | peru | pink | plum | purple | red | salmon | sienna | silver | snow | tan | teal | thistle | tomato | turquoise | violet | white | yellow ;'
var recognition = new SpeechRecognition();
var speechRecognitionList = new SpeechGrammarList();
speechRecognitionList.addFromString(grammar, 1);
recognition.grammars = speechRecognitionList;
//recognition.continuous = false;
recognition.lang = 'en-US';
recognition.interimResults = false;
recognition.maxAlternatives = 1;

...

Specifications

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support33 webkit 1 ? No No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes webkit 1 Yes webkit 1 ? No No No ?

1. You'll need to serve your code through a web server for recognition to work.

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

Document Tags and Contributors

Contributors to this page: lucian95, chrisdavidmills
Last updated by: lucian95,