<?php
// Regex by Geert De Deckere <geert@kohanaphp.com>
function valid_email($email)
{
return (bool) preg_match('/^[-_a-z0-9\'+*$^&%=~!?{}]++(?:\.[-_a-z0-9\'+*$^&%=~!?{}]+)*+@(?:(?![-.])[-a-z0-9.]+(?<![-.])\.[a-z]{2,6}|\d{1,3}(?:\.\d{1,3}){3})(?::\d++)?$/iD', $email);
}