| title | slug | page-type | browser-compat |
|---|---|---|---|
Date.prototype.getTime() |
Web/JavaScript/Reference/Global_Objects/Date/getTime |
javascript-instance-method |
javascript.builtins.Date.getTime |
{{JSRef}}
The getTime() method of {{jsxref("Date")}} instances returns the number of milliseconds for this date since the epoch, which is defined as the midnight at the beginning of January 1, 1970, UTC.
{{EmbedInteractiveExample("pages/js/date-gettime.html", "shorter")}}
getTime()
None.
A number representing the timestamp, in milliseconds, of this date. Returns NaN if the date is invalid.
Date objects are fundamentally represented by a timestamp, and this method allows you to retrieve the timestamp. You can use this method to help assign a date and time to another {{jsxref("Date")}} object. This method is functionally equivalent to the {{jsxref("Date/valueof", "valueOf()")}} method.
Constructing a date object with the identical time value.
// Since month is zero based, birthday will be January 10, 1995
const birthday = new Date(1994, 12, 10);
const copy = new Date();
copy.setTime(birthday.getTime());Subtracting two subsequent getTime() calls on newly generated {{jsxref("Date")}} objects, give the time span between these two calls. This can be used to calculate the executing time of some operations. See also {{jsxref("Date.now()")}} to prevent instantiating unnecessary {{jsxref("Date")}} objects.
let end, start;
start = new Date();
for (let i = 0; i < 1000; i++) {
Math.sqrt(i);
}
end = new Date();
console.log(`Operation took ${end.getTime() - start.getTime()} msec`);Note
In browsers that support the {{domxref("Performance API", "", "", "nocode")}}'s high-resolution time feature, {{domxref("Performance.now()")}} can provide more reliable and precise measurements of elapsed time than {{jsxref("Date.now()")}}.
{{Specifications}}
{{Compat}}
- {{jsxref("Date.prototype.setTime()")}}
- {{jsxref("Date.prototype.valueOf()")}}
- {{jsxref("Date.now()")}}