BaseAudioContext.currentTime

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.

Syntax

var curTime = baseAudioContext.currentTime;

Example

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

...

console.log(audioCtx.currentTime);

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
audioCtx.currentTime;
// 23.404
// 24.192
// 25.514
// ...


// reduced time precision with `privacy.resistFingerprinting` enabled
audioCtx.currentTime;
// 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.

Specifications

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
currentTimeChrome Full support 10
Prefixed
Full support 10
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Edge Full support YesFirefox Full support 25IE No support NoOpera Full support 22
Full support 22
Full support 15
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari Full support 6
Prefixed
Full support 6
Prefixed
Prefixed Implemented with the vendor prefix: webkit
WebView Android Full support YesChrome Android Full support 33Firefox Android Full support 26Opera Android Full support 22
Full support 22
Full support 14
Prefixed
Prefixed Implemented with the vendor prefix: webkit
Safari iOS No support NoSamsung Internet Android Full support Yes

Legend

Full support  
Full support
No support  
No support
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also: