JavaScript now() Method

Return the number of milliseconds since 1970/01/01:

var n = Date.now();

More "Try it Yourself" examples below.

Definition and Usage

The Date.now() method returns the number of milliseconds since January 1, 1970 00:00:00 UTC.

Method
Date.now()	Yes	9	Yes	Yes	Yes

Date.now()

None

Return Value:	A Number, representing the number of milliseconds since midnight January 1, 1970
JavaScript Version:	ECMAScript 5 (2009)

Calculate the number of years since 1970/01/01:

var minutes = 1000 * 60;
var hours = minutes * 60;
var days = hours * 24;
var years = days * 365;
var t = Date.now();

var y = Math.round(t / years);

JavaScript Tutorial: JavaScript Dates