Untitled

$email_regex = "[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?";

if (!isset($fields['email_address']) || !preg_match($email_regex,$fields['email_address'])) $errors.='Email address not set or not valid.<br />';