用户注册时不用填邮箱都可以注册的修改方法

vgo168

if(!is_email($email)) exit('2');
        if($do->email_exists($email)) exit('3');
        if(!$do->is_email($email)) exit('4');
        $emailcode = random(6, '0123456789');
        $_SESSION['email'] = $email;
        $_SESSION['email_code'] = md5($email.'|'.$emailcode);
        $title = $L['register_msg_emailcode'];
        $content = ob_template('emailcode', 'mail');
        send_mail($email, $title, stripslashes($content));
        exit('1');
}


请帮忙改一下