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 APIThe definition of 'currentTime' in that specification. | Working Draft | Initial definition. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
currentTime
|
Chrome Full support 10 Full support 10 Prefixed' Implemented with the vendor prefix: webkit |
Edge
Full support ≤18 |
Firefox Full support 53 Full support 53 Notes' Originally implemented on |
IE
No support No |
Opera Full support 22 Full support 22 Full support 15 Prefixed' Implemented with the vendor prefix: webkit |
Safari Full support 6 Full support 6 Prefixed' Implemented with the vendor prefix: webkit |
WebView Android
Full support Yes |
Chrome Android
Full support 33 |
Firefox Android Full support 53 Full support 53 Notes' Originally implemented on |
Opera Android Full support 22 Full support 22 Full support 14 Prefixed' Implemented with the vendor prefix: webkit |
Safari iOS Full support 6 Full support 6 Prefixed' Implemented with the vendor prefix: webkit |
Samsung Internet Android
Full support 2.0 |
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.'
- See implementation notes.
- Requires a vendor prefix or different name for use.'
- Requires a vendor prefix or different name for use.
See also:
BaseAudioContext.currentTime by Mozilla Contributors is licensed under CC-BY-SA 2.5.