Change the browser's Date/time value using chrome extension

Question

I'm looking for a way to change the value returned from javascript's new Date() function.
In general - I'm looking for a way to write an extension that will give the user the ability to set his timezone (or diff from the time of his system's clock) without changing time/timezone on his computer.

I checked the chrome extension api but found nothing there. Will appreciate it if someone can point me at the right direction.

Answer 1

I have seen some solutions involving overriding javascript's getTime() method:

Date.prototype.getTime = function() { return [DATE + OFFSET] };

usage:

(new Date).getTime();

(source)

Apparently the time does not come from the browser but rather the operating system. So my suggestion would be to inject this javascript using a content script, and in your overriding function, you can offset the date/time by however much you would like.