The Date.now()
method returns the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC.
Syntax
var timeInMs = Date.now();
Return value
A Number
representing the milliseconds elapsed since the UNIX epoch.
Description
Because now()
is a static method of Date
, you always use it as Date.now()
.
Polyfill
This method was standardized in ECMA-262 5th edition. Engines which have not been updated to support this method can work around the absence of this method using the following shim:
if (!Date.now) { Date.now = function now() { return new Date().getTime(); }; }
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 5.1 (ECMA-262) The definition of 'Date.now' in that specification. |
Standard | Initial definition. Implemented in JavaScript 1.5. |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Date.now' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Date.now' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 5 | 3.0 (1.9) | 9 | 10.50 | 4 |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
See also
Performance.now()
— provides timestamps with sub-millisecond resolution for use in measuring web page performanceconsole.time()
/console.timeEnd()
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