The length property of the AudioBuffer interface returns an integer representing the length, in sample-frames, of the PCM data stored in the buffer.

AudioBuffer 的length属性接口返回整数,该整数代表采样帧中,存贮在缓冲区中的PCM数据的长度


var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);



// Stereo
var channels = 2;

// Create an empty two second stereo buffer at the
// sample rate of the AudioContext
var frameCount = audioCtx.sampleRate * 2.0;
var myArrayBuffer = audioCtx.createBuffer(2, frameCount, audioCtx.sampleRate);

button.onclick = function() {
  // Fill the buffer with white noise;
  // just random values between -1.0 and 1.0
  for (var channel = 0; channel < channels; channel++) {
    // This gives us the actual ArrayBuffer that contains the data
    var nowBuffering = myArrayBuffer.getChannelData(channel);
    for (var i = 0; i < frameCount; i++) {
      // Math.random() is in [0; 1.0]
      // audio needs to be in [-1.0; 1.0]
      nowBuffering[i] = Math.random() * 2 - 1;



Specification Status Comment
Web Audio API
Working Draft  


We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)
Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 14 webkit (en-US) (Yes) 23 未实现 15 webkit (en-US)
22 (unprefixed)
6 webkit (en-US)
Feature Android Chrome Edge Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 未实现 28 webkit (en-US) (Yes) 25 1.2 未实现 未实现 webkit (en-US)

See also