Javascript – Display date/time in user’s locale format and time offset

datetimejavascripttimezone

I want the server to always serve dates in UTC in the HTML, and have JavaScript on the client site convert it to the user's local timezone.

Bonus if I can output in the user's locale date format.

Best Solution

Seems the most foolproof way to start with a UTC date is to create a new Date object and use the setUTC… methods to set it to the date/time you want.

Then the various toLocale…String methods will provide localized output.

Example:

// This would come from the server.
// Also, this whole block could probably be made into an mktime function.
// All very bare here for quick grasping.
d = new Date();
d.setUTCFullYear(2004);
d.setUTCMonth(1);
d.setUTCDate(29);
d.setUTCHours(2);
d.setUTCMinutes(45);
d.setUTCSeconds(26);

console.log(d);                        // -> Sat Feb 28 2004 23:45:26 GMT-0300 (BRT)
console.log(d.toLocaleString());       // -> Sat Feb 28 23:45:26 2004
console.log(d.toLocaleDateString());   // -> 02/28/2004
console.log(d.toLocaleTimeString());   // -> 23:45:26

Some references: