Well...it's isn't independant of the server time. And yet...it is, sort of.
What you do is store all values in the server relative to a specific time zone (which can be the time zone the server normally lives in but that can be a bad idea) - and the best zone to pick is UCT:
Universal Coordinated Time[
^] which isn't a time zone at all! :laugh:
UTC is referenced to a single geographic line of longitude and is never affected by "summer time" or "winter time", and is the base for all world time zones. If you store your values in UTC, then you can convert them on the fly to the local time for the correct user anywhere in the world - and the local time will take care of plus or minus x hours, summer time, and so forth. So what your user ends up with is the time specific to their current location, regardless of where in the world they log in from.