login form validation problem

Hi I am trying to display a javascript alert if a user either doesnt fill the login form or enters the wrong data but for some reason when ever I try to add the varible to the alert function it doesnt work. heres the code

 <?php if ($this->getBuffer('message')) : ?>
                    <?php $message = strip_tags($this->getBuffer('message')); ?>
                    <script>alert("$message")</script>
                <?php endif; ?>

PHP:

If any one can help or even better now of a good plugin for the login form which has good validation.