index.html

---
title: SpeechRecognitionResult.length
slug: Web/API/SpeechRecognitionResult/length
tags:
- API
- Experimental
- Property
- Reference
- SpeechRecognitionResult
- Web Speech API
- length
- recognition
- speech
browser-compat: api.SpeechRecognitionResult.length
---
<p>{{APIRef("Web Speech API")}}{{ SeeCompatTable() }}</p>

<p>The <code><strong>length</strong></code> read-only property of the
  {{domxref("SpeechRecognitionResult")}} interface returns the length of the "array"
    — the number of {{domxref("SpeechRecognitionAlternative")}} objects contained
  in the result (also referred to as "n-best alternatives".)</p>

<p>The number of alternatives contained in the result depends on what the
  {{domxref("SpeechRecognition.maxAlternatives")}} property was set to when the speech
  recognition was first initiated.</p>

<h2 id="Syntax">Syntax</h2>

<pre
  class="brush: js">var myLength = speechRecognitionResultInstance.length;</pre>

<h3 id="Returns">Returns</h3>

<p>A number.</p>

<h2 id="Examples">Examples</h2>

<p>This code is excerpted from our <a
    href="https://github.com/mdn/web-speech-api/blob/master/speech-color-changer/script.js">Speech
    color changer</a> example.</p>

<pre class="brush: js">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);
}</pre>

<h2 id="Specifications">Specifications</h2>

{{Specifications}}

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{Compat}}</p>

<h3 id="Firefox_OS_permissions">Firefox OS permissions</h3>

<p>To use speech recognition in an app, you need to specify the following permissions in
  your <a href="/en-US/docs/Web/Apps/Build/Manifest">manifest</a>:</p>

<pre class="brush: json">"permissions": {
  "audio-capture" : {
    "description" : "Audio capture"
  },
  "speech-recognition" : {
    "description" : "Speech recognition"
  }
}</pre>

<p>You also need a privileged app, so you need to include this as well:</p>

<pre class="brush: json">  "type": "privileged"</pre>

<h2 id="See_also">See also</h2>

<ul>
  <li><a href="/en-US/docs/Web/API/Web_Speech_API">Web Speech API</a></li>
</ul>