Using PHP's listidentifiers (part of the DateTimeZone class ), we can create a dropdown menu of all available global timezone identifiers. It's handy for inclusion in forms if you're after a general region rather than just country.
The first function retrieves timezone values and returns an array:
The second function retrieves the timezone array and manufactures the select menu.
Usage is as follows:
/* Usage */ echo beliefmedia_timezones();
The results is as follows:
Note: I've included raw HTML to show the list so timezone values may not be correct.