how to know user time zone from script include.

Hi, 

I have the date field in my catalog item and auto populate default date something, i have done that, but the issue is, it is showing different because of user based on user time zone. 

so, for that i need to write script to validate whether the user time zone is universal if not how to check the user time zone.

example ; i am in universal time zone but my colleague in japan i need to add utc + 9hrs how to write the script please suggest.

thanks

venkatesh t