Web/API/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 [[../../../../../../../mdn.github.io/violent-theremin/index|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 APIThe definition of 'start' in that specification.	Working Draft

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`start`	Chrome Full support 14	Edge Full support 12	Firefox Full support 25 Notes' Full support 25 Notes' Notes' Before Firefox 30, the `when` parameter was not optional.	IE No support No	Opera Full support 15	Safari Full support 6	WebView Android Full support Yes	Chrome Android Full support 18	Firefox Android Full support 26 Notes' Full support 26 Notes' Notes' Before Firefox 30, the `when` parameter was not optional.	Opera Android Full support 14	Safari iOS ?	Samsung Internet Android Full support 1.0

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown
See implementation notes.': See implementation notes.