OscillatorNode.start() - Web APIs 编辑

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

Browser compatibility

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See also

• Using the Web Audio API