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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 compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 14 12 25
25
Before Firefox 30, the when parameter was not optional.
No 15 6
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support Yes 18 Yes 26
26
Before Firefox 30, the when parameter was not optional.
15 ? Yes

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/OscillatorNode/start