<?php $email = $_POST['email']; if(<a href="http://www.php.net/preg_match">preg_match</a>("~([a-zA-Z0-9!#$%&\'*+-/=?^_`{|}\~])@([a-zA-Z0-9-]).([a-zA-Z0-9]{2,4})~", $email)){ <a href="http://www.php.net/echo">echo</a> 'Верно'; }else{ <a href="http://www.php.net/echo">echo</a> 'Неверно'; } ?>