Handling dates (formatting and timezones) in javascript

The use case is that I am getting the date in millis (from epoch) through an ajax call, which now needs to be interpreted in the javascript. This corresponded to some point of time in UTC.

Now I need to display this 开发者_运维问答date in PST, as that is the only relevant time zone for the users irrespective of where they are opening the page from. Also, I need to show it in a different format like 'yyyy-mm-dd HH:mm' rather than the default Locale string.

Can someone please tell me, how I can do that.

Create a new date using the UNIX milliseconds value plus the offset to PST, then create your formatted string using getUTC series of calls.

Moment.js is a pretty nice library for this type of thing.

I believe the timezones are determined by the user's timezone setting when you use the new Date() function.

var myDateTime = 1312312732923; 
var myDate = new Date(myDateTime); 

var myFormattedDate = myDate.getFullYear() + "-" + (myDate.getMonth()+1) + "-" + myDate.getDay();

http://www.w3schools.com/jsref/jsref_obj_date.asp

JavaScript has now way to set the timezone that you want to display something in. I've used Flot for a library for charting and their suggested solution is to use the getUTC methods when displaying the dates. That means that your server code can't send the standard millis from epoch (since that would display GMT time), but a small adjustment on the server will make your dates display correctly on the client.

To read about the problem, see http://flot.googlecode.com/svn/trunk/API.txt, and look for the heading "Time series data"

Use the Date object: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Date

Javascript's Date object works with milliseconds rather than seconds, so you'll have to multiply a UNIX timestamp by 1000:

var myDate = new Date(unix_timestamp * 1000);

Then, you can use the local-specific Date object to do whatever you'd like:

var output = myDate .getHours() + ':';
output += myDate .getMinutes() + ':';
output += myDate .getSeconds();
alert(output);

EDIT Ah, missed the part about using PST always, regardless of locale. unix_timesamp again is the epoch/UNIX timestamp you're getting from the server:

Try it here: http://jsfiddle.net/46PYZ/

  // set to the UTC offset for the target timezone, PST = UTC - 8
    var target_offset = -8;

    // create a Date object
    var myDate = new Date();

    // add local time zone offset to get UTC time in msec
    var utc_milliseconds = (unix_timesamp * 1000) + (myDate .getTimezoneOffset() * 60000);

    // set the time using the calculated UTC timestamp
    myDate.setTime(utc_milliseconds + (3600000 * target_offset));

    // now build the yyyy-mm-dd HH:mm format
    var output = myDate.getFullYear() + '-';
    var month = myDate.getMonth() + 1;
    output += (month < 10 ? '0' + month : month) + '-';
    output += myDate.getDate() + ' ';
    var hours = myDate.getHours() + 1;
    output += (hours < 10 ? '0' + hours : hours) + ':';
    var minutes= myDate.getMinutes() + 1;
    output += (minutes< 10 ? '0' + minutes : minutes);