How to validate non-english (UTF-8) encoded email address in Javascript and PHP?

Question

Part of a website I am currently working on contains registration process where users have to provide their email address. Just recently I became aware that non-ascii based

Answer 1

what is about something this:

mb_internal_encoding("UTF-8");
mb_regex_encoding("UTF-8");
mb_ereg('[\w]+@[\w]+\.com',$mail,'UTF-8');