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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

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support14 ?25 No15 ?
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support1414 ?25 No15 ?

See also

Document Tags and Contributors

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