From http://www.w3schools.com (Copyright Refsnes Data)

JavaScript UTC() Method

Date Object Reference JavaScript Date Object

Definition and Usage

The UTC() method takes a date and returns the number of milliseconds since midnight of January 1, 1970 according to universal time.

Syntax

Date.UTC(year,month,day,hours,minutes,seconds,ms)

Parameter Description
year Required. A four digit number representing the year
month Required. An integer between 0 and 11 representing the month
day Required. An integer between 1 and 31 representing the date
hours Optional. An integer between 0 and 23 representing the hour
minutes Optional. An integer between 0 and 59 representing the minutes
seconds Optional. An integer between 0 and 59 representing the seconds
ms Optional. An integer between 0 and 999 representing the milliseconds

Examples

Example 1

Get how many milliseconds there are from 1970/01/01 to 2005/07/08 according to universal time:

<script type="text/javascript">

var d=Date.UTC(2005,7,8);
document.write(d);

</script>

The output of the code above will be:

1123459200000

Try it yourself »

Example 2

Convert the output from the example above into years:

<script type="text/javascript">

var minutes=1000*60;
var hours=minutes*60;
var days=hours*24;
var years=days*365;
var t=Date.UTC(2005,7,8);
var y=t/years;
document.write("It's been: " + y + " years from 1970/01/01");
document.write(" to 2005/07/08!");

</script>

The output of the code above will be:

It's been: 35.62465753424657 years from 1970/01/01 to 2005/07/08!

Try it yourself »

Date Object Reference JavaScript Date Object

From http://www.w3schools.com (Copyright Refsnes Data)