The start() method on AudioScheduledSourceNode schedules a sound to begin playback at the specified time. If no time is specified, then the sound begins playing immediately.


AudioScheduledSourceNode.start([when [, offset [, duration]]]);


when Optional
The time, in seconds, at which the sound should begin to play. This value is specified in the same time coordinate system as the AudioContext is using for its currentTime attribute. A value of 0 (or omitting the when parameter entirely) causes the sound to start playback immediately.
offset Optional
A floating-point number indicating the offset, in seconds, into the audio buffer where playback should begin. If 0 is passed then the playback will start from the beginning.
duration Optional
A floating-point number indicating the duration, in seconds, to be played. If no value is passed then the duration will be equal to the length of the audio buffer minus the offset value

Return value



The value specified for when is negative.




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

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 56.0[1] ? 53 (53)  No support 43[1] ?
Feature Android Webview Edge Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support 56.0[1] ? 53.0 (53) ? ? 43[1] ? 56.0[1]

[1] Chrome and Opera implement this method on the ConstantSourceNode interface.

See also

Document Tags and Contributors

 Contributors to this page: nbriz, jpmedley, Sheppy
 Last updated by: nbriz,