SpeechRecognitionResult.length

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

The length read-only property of the SpeechRecognitionResult interface returns the length of the "array" — the number of SpeechRecognitionAlternative objects contained in the result (also referred to as "n-best alternatives".)

The number of alternatives contained in the result depends on what the SpeechRecognition.maxAlternatives property was set to when the speech recognition was first initiated.

Syntax

var myLength = speechRecognitionResultInstance.length;

Returns

A number.

Examples

This code is excerpted from our Speech color changer example.

recognition.onresult = function(event) {
  // The SpeechRecognitionEvent results property returns a SpeechRecognitionResultList object
  // The SpeechRecognitionResultList object contains SpeechRecognitionResult objects.
  // It has a getter so it can be accessed like an array
  // The first [0] returns the SpeechRecognitionResult at position 0.
  // Each SpeechRecognitionResult object contains SpeechRecognitionAlternative objects that contain individual results.
  // These also have getters so they can be accessed like arrays.
  // The second [0] returns the SpeechRecognitionAlternative at position 0.
  // We then return the transcript property of the SpeechRecognitionAlternative object
  var color = event.results[0][0].transcript;
  diagnostic.textContent = 'Result received: ' + color + '.';
  bg.style.backgroundColor = color;

  console.log(event.results[0].length);
}

Specifications

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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
length
Experimental
Chrome Full support 33
Prefixed Notes
Full support 33
Prefixed Notes
Prefixed Implemented with the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Edge Full support ≤79
Prefixed Notes
Full support ≤79
Prefixed Notes
Prefixed Implemented with the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Firefox No support NoIE No support NoOpera No support NoSafari No support NoWebView Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Implemented with the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Chrome Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Implemented with the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.
Firefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android Full support Yes
Prefixed Notes
Full support Yes
Prefixed Notes
Prefixed Implemented with the vendor prefix: webkit
Notes You'll need to serve your code through a web server for recognition to work.

Legend

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also