Validate email. Javascript and PHP

Javascript

function validateEmail(email) { 
    var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    return re.test(email);}

PHP

function validEmail($email ) {
         $regexp = '/^[\w\-\.]+@[\w\-]+(\.[\w\-]+)*(\.[a-z]{2,})$/';
         if ( preg_match($regexp , $email ) ){
             //list ($user,$domain) = explode('@', $email, 2);                       
             return true;
         }
         return false;
     }