TIMEZONE help

[miniz98]

hey im writing a page that does the timezones for 5:00 around the world and i found this template the only thing is it didnt include the timezone.php file the js is loading this new Ajax('timezone.php?tz='+String(timezone),{onComplete:tzCLB, method: 'get'}).request();

 

what it does is retrieves a list of countries from that file i think. How and what would i need to do to make a timezone.php that would get the countries. Thanks