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The currentTime read-only property of the BaseAudioContext interface returns a double representing an ever-increasing hardware timestamp in seconds that can be used for scheduling audio playback, visualizing timelines, etc. It starts at 0.


var curTime = baseAudioContext.currentTime;


var AudioContext = window.AudioContext || window.webkitAudioContext;
var audioCtx = new AudioContext();
// Older webkit/blink browsers require a prefix



Reduced time precision

To offer protection against timing attacks and fingerprinting, the precision of audioCtx.currentTime might get rounded depending on browser settings.
In Firefox, the privacy.reduceTimerPrecision  preference is enabled by default and defaults to 20us in Firefox 59; in 60 it will be 2ms.

// reduced time precision (2ms) in Firefox 60
// 23.404
// 24.192
// 25.514
// ...

// reduced time precision with `privacy.resistFingerprinting` enabled
// 49.8
// 50.6
// 51.7
// ...

In Firefox, you can also enabled privacy.resistFingerprinting, the precision will be 100ms or the value of privacy.resistFingerprinting.reduceTimerPrecision.microseconds, whichever is larger.


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

Browser compatibility:

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 10.0webkit (Yes) 25.0 (25.0)  No support 15.0webkit
22 (unprefixed)
Feature Android Edge Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support ? (Yes) 26.0 1.2 ? ? ? 33.0


See also:

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Last updated by: fscholz,