How do I set a countdown's target time to be in a set time zone?

Question

I'm working on a countdown webpage for a huge update on a game that will be a big thing and whatnot. That countdown is working currently with this code getting the times of the computer, the target end time and the time difference:

var christmas = new Date("December 25, 2014 00:01:00");
var now = new Date();
var timeDiff = christmas.getTime() - now.getTime();

I need a way to get the christmas target time to be in the same timezone no matter what your computer's timezone is set to.

Answer 1

Use UTC:

var xmas = new Date('2014-12-25T00:00:01.0000000'); 
var utc = new Date(
              xmas.getUTCFullYear(),
              xmas.getUTCMonth(),
              xmas.getUTCDate(),
              xmas.getUTCHours(),
              xmas.getUTCMinutes(),
              xmas.getUTCSeconds()
          );

alert('local diff: ' + (xmas.getTime() - new Date().getTime()));
alert('utc diff: ' + (utc.getTime() - new Date().getTime()));