SpeechRecognitionEvent.resultIndex

The resultIndex read-only property of the SpeechRecognitionEvent interface returns the lowest index value result in the SpeechRecognitionResultList "array" that has actually changed.

The SpeechRecognitionResultList object is not an array, but it has a getter that allows it to be accessed by array syntax.

Syntax

var myResultIndex = event.resultIndex;

Value

A number.

Examples

recognition.onresult = function(event) {
  var color = event.results[0][0].transcript;
  diagnostic.textContent = 'Result received: ' + color + '.';
  bg.style.backgroundColor = color;
  console.log(event.resultIndex); // returns 0 if there is only one result
}

Specifications

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

Browser compatibility

• [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

• Web Speech API