Event.timeStamp

Baseline Widely available

This feature is well established and works across many devices and browser versions. Itâs been available across browsers since Ð¸ÑÐ»Ñ 2015 Ð³..

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event.timeStamp

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In newer implementations, the value is a DOMHighResTimeStamp accurate to 5 microseconds (0.005 ms). In older implementations, the value is a DOMTimeStamp, accurate to a millisecond.

Example

HTML content

html

<p>
  Focus this iframe and press any key to get the current timestamp for the
  keypress event.
</p>
<p>timeStamp: <span id="time">-</span></p>

JavaScript content

function getTime(event) {
  var time = document.getElementById("time");
  time.firstChild.nodeValue = event.timeStamp;
}
document.body.addEventListener("keypress", getTime);

To offer protection against timing attacks and fingerprinting, the precision of event.timeStamp 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
event.timeStamp;
// 1519211809934
// 1519211810362
// 1519211811670
// ...

// reduced time precision with `privacy.resistFingerprinting` enabled
event.timeStamp;
// 1519129853500
// 1519129858900
// 1519129864400
// ...

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