Convert the facebook time to GMT format?

In my website I am using facebook application.And if user loged in with facebook then facebook provide the timezone information like 5.5 for (GMT+05:30) Chennai, Kolkata, Mumbai, New Delhi.So I need to convert for all timezones.I开发者_开发知识库s there any simple coding for that otherwise I need all timezone information in facebook format with GMT format?

looks to me like you might need to build an array linking the facebook time values with the supported time zones from php... because no class in php does what you want.

Maybe you should post your issue on the facebook developers forums, they might be able to help you with that!