OscillatorNode.start()

The start method of the OscillatorNode interface specifies the exact time to start playing the tone. Its parameter is optional and default to 0.

Syntax

oscillator.start(when); // start playing oscillator at the point in time specified by when

Parameters

when Optional
An optional double representing the time (in seconds) when the oscillator should start, in the same coordinate system as AudioContext's currentTime attribute. If a value is not included or is less than currentTime, the oscillator starts playing immediately.

Example

The following example shows basic usage of an AudioContext to create an oscillator node. For an applied example, check out our Violent Theremin demo (see app.js for relevant code).

// create web audio api context
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();

// create Oscillator node
var oscillator = audioCtx.createOscillator();

oscillator.type = 'square';
oscillator.frequency.setValueAtTime(3000, audioCtx.currentTime); // value in hertz
oscillator.start();

Specifications

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support1412251 No156
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support1418 Yes26115 ? Yes

1. Before Firefox 30, the when parameter was not optional.

See also

Document Tags and Contributors

Last updated by: tszynalski,