在此页

• 句法
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

这是 实验性技术
检查 浏览器兼容性表格 要小心谨慎在生产中使用这之前。

length 只读特性在 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.

句法

var myLength = speechRecognitionResultInstance.length;
					

返回

A number.

范例

This code is excerpted from our Speech color changer 范例。

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);
}
					

规范

规范	状态	注释
Web 语音 API The definition of 'length' in that specification.	草案

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
length	Chrome 33 Prefixed 33 Prefixed Prefixed Implemented with the vendor prefix: webkit You'll need to serve your code through a web server for recognition to work.	Edge ≤79 Prefixed ≤79 Prefixed Prefixed Implemented with the vendor prefix: webkit You'll need to serve your code through a web server for recognition to work.	Firefox No	IE No	Opera No	Safari No	WebView Android Yes Prefixed Yes Prefixed Prefixed Implemented with the vendor prefix: webkit You'll need to serve your code through a web server for recognition to work.	Chrome Android Yes Prefixed Yes Prefixed Prefixed Implemented with the vendor prefix: webkit You'll need to serve your code through a web server for recognition to work.	Firefox Android No	Opera Android No	Safari iOS No	Samsung Internet Android Yes Prefixed Yes Prefixed Prefixed Implemented with the vendor prefix: webkit You'll need to serve your code through a web server for recognition to work.

图例

完整支持

完整支持

不支持

不支持

实验。期望将来行为有所改变。

实验。期望将来行为有所改变。

见实现注意事项。

要求使用供应商前缀或不同名称。

要求使用供应商前缀或不同名称。

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"
										

另请参阅

• Web 语音 API

元数据

• 最后修改： 2020 年 1 月 22 日

相关话题

1. SpeechRecognitionResult
2. 特性

   1. isFinal
   2. length
3. 方法

   1. item()
4. Related pages for Web Speech API

   1. SpeechGrammar
   2. SpeechGrammarList
   3. SpeechRecognition
   4. SpeechRecognitionAlternative
   5. SpeechRecognitionError
   6. SpeechRecognitionEvent
   7. SpeechRecognitionResultList
   8. SpeechSynthesis
   9. SpeechSynthesisErrorEvent
   10. SpeechSynthesisEvent
   11. SpeechSynthesisUtterance
   12. SpeechSynthesisVoice