<?php
function valid_email($adres){
    if (!eregi("^([a-z0-9_-]+)(\.[a-z0-9_-]+)*@([a-z0-9_-]*)+(\.[a-z0-9_-]+)*(\.[a-z]{2,})$", $adres)){
        return false;
    }else{
        return $adres;
    }
}
?>