title: How to validate non-english (UTF-8) encoded email address in Javascript and PHP?
body: <p>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 domains are possible (so is email).
  My backend is utf-8 encoded MySQL where I am expecting any users (with differnt locales) should be able to enter their email but don't know how to validate this kind of email address.</p>
  
  <p>Currently I am testing out jquery tools and it validates the english email address correctly but fails to validate non ascii email. Also I need to do same at server side with php. Is there a regular expression that can validate this kind of email address?</p>
  
  <p>I have tried this but it fails in jquery tools (this is just example for demo, I don't understand this too)</p>
  
  <p>闪闪发光@闪闪发光.com</p>
  
  <p>Also what will happen when they type their English email address (jonesmith@somemail.com) with their own IME. Can this be validated with current regular expression we have for English mail validation. Currently I don't have to worry if that email exist for not. </p>
  
  <p>Thanks</p>