The getTime()
method returns the number of milliseconds* since the Unix Epoch.
* JavaScript uses milliseconds as the unit of measurement, whereas Unix Time is in seconds.
getTime() always uses UTC for time representation. For example, a client browser in one timezone, getTime() will be the same as a client browser in any other timezone.
You can use this method to help assign a date and time to another Date
object. This method is functionally equivalent to the valueOf()
method.
The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.
Syntax
dateObj.getTime()
Return value
A number representing the milliseconds elapsed between 1 January 1970 00:00:00 UTC and the given date.
Reduced time precision
To offer protection against timing attacks and fingerprinting, the precision of new Date().getTime()
might get rounded depending on browser settings. In Firefox, the privacy.reduceTimerPrecision
preference is enabled by default and defaults to 20ยตs in Firefox 59; in 60 it will be 2ms.
// reduced time precision (2ms) in Firefox 60 new Date().getTime(); // 1519211809934 // 1519211810362 // 1519211811670 // ... // reduced time precision with `privacy.resistFingerprinting` enabled new Date().getTime(); // 1519129853500 // 1519129858900 // 1519129864400 // ...
In Firefox, you can also enable privacy.resistFingerprinting
, the precision will be 100ms or the value of privacy.resistFingerprinting.reduceTimerPrecision.microseconds
, whichever is larger.
Examples
Using getTime()
for copying dates
Constructing a date object with the identical time value.
// Since month is zero based, birthday will be January 10, 1995 var birthday = new Date(1994, 12, 10); var copy = new Date(); copy.setTime(birthday.getTime());
Measuring execution time
Subtracting two subsequent getTime()
calls on newly generated Date
objects, give the time span between these two calls. This can be used to calculate the executing time of some operations. See also Date.now()
to prevent instantiating unnecessary Date
objects.
var end, start; start = new Date(); for (var i = 0; i < 1000; i++) { Math.sqrt(i); } end = new Date(); console.log('Operation took ' + (end.getTime() - start.getTime()) + ' msec');
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Date.prototype.getTime' in that specification. |
Browser compatibility
The compatibility table in 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.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
getTime | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 4 | Opera Full support 3 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 10.1 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 | nodejs Full support 0.1.100 |
Legend
- Full support
- Full support