Alessandro Lacava

on Designing and Developing Software. In love with Functional Programming.

How to Compute the Timestamp In JavaScript

Many sources use the term timestamp to refer specifically to Unix time, the number of seconds since 00:00:00 UTC on January 1, 1970. In JavaScript you can use the built-in object Date to compute this timestamp. Here follows an example:

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var ts = Date.UTC('2007', '09', '28') / 1000;
alert(ts);

The previous code displays an alert with the number of seconds between 00:00:00 UTC on January 1, 1970 and 00:00:00 UTC on October 28, 2007.

How it works:

UTC is a static method of the Date object. The complete signature of this method is the following:

UTC(year, month, [day], [hours], [minutes], [seconds], [milliseconds])

Note that the parameters between square brackets are optional. The UTC method returns the number of milliseconds using UTC (Universal Time Coordinated). Hence the following code:

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Date.UTC('2007', '09', '28') / 1000;

computes the number of seconds between 00:00:00 UTC on January 1, 1970 and 00:00:00 UTC on October 28, 2007. Note that the month parameter ranges from 0 (Jan) to 11 (Dec).

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