The loopEnd property of the AudioBufferSourceNode interface specifies is a floating point number specifying, in seconds, at what offset into playing the AudioBuffer playback should loop back to the time indicated by the loopStart property. This is only used if the loop property is true.


AudioBufferSourceNode.loopEnd = endOffsetInSeconds;

var endOffsetInSeconds = AudioBufferSourceNode.loopEnd;


A floating-point number indicating the offset, in seconds, into the audio buffer at which each loop will loop return to the beginning of the loop (that is, the current play time gets reset to AudioBufferSourceNode.loopStart). This property is only used if the loop property is true.

The default value is 0.


In this example, the AudioContext.decodeAudioData() function is used to decode an audio track and put it into an AudioBufferSourceNode. Buttons are provided to play and stop the audio playback, and slider controls are used to change the playbackRate, loopStart and loopEnd properties on the fly.

When the audio is played to the end, it loops, but you can control how long the loops last by altering loopStart and loopEnd. For example, if you set their values to 20 and 25, respectively, then begin playback, the sound will play normally until it reaches the 25 second mark. Then the current play position will loop back to the 20 second mark and continue playing until the 25 second mark, ad infinitum (or at least until stop() is called).

For a full working example, see this code running live, or view the source.

function getData() {
  source = audioCtx.createBufferSource();
  request = new XMLHttpRequest();'GET', 'viper.ogg', true);

  request.responseType = 'arraybuffer';

  request.onload = function() {
    var audioData = request.response;

    audioCtx.decodeAudioData(audioData, function(buffer) {
        myBuffer = buffer;
        songLength = buffer.duration;
        source.buffer = myBuffer;
        source.playbackRate.value = playbackControl.value;
        source.loop = true;

        loopstartControl.setAttribute('max', Math.floor(songLength));
        loopendControl.setAttribute('max', Math.floor(songLength));

      function(e){"Error with decoding audio data" + e.err});




loopstartControl.oninput = function() {
  source.loopStart = loopstartControl.value;
  loopstartValue.innerHTML = loopstartControl.value;

loopendControl.oninput = function() {
  source.loopEnd = loopendControl.value;
  loopendValue.innerHTML = loopendControl.value;


Specification Status Comment
Web Audio API
The definition of 'loopEnd' in that specification.
Working Draft  

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
loopEndChrome Full support 24Edge Full support 12Firefox Full support 25IE No support NoOpera Full support 15Safari Full support 6WebView Android Full support ≤37Chrome Android Full support 25Firefox Android Full support 26Opera Android Full support 14Safari iOS Full support 6Samsung Internet Android Full support 1.5


Full support  
Full support
No support  
No support

See also