Greybox Popup!

[liamloveslearning]

Hi all, I have a form, on submit i want it to open a lightbox/popup. My script is as follows

 

  <script type="text/javascript" src="http://jquery.com/src/latest/"></script>
    <script type="text/javascript" src="greybox/greybox.js"></script>
    <link href="greybox/greybox.css" rel="stylesheet" type="text/css" media="all" />
    <script type="text/javascript">
      var GB_ANIMATION = true;
      $(document).ready(function(){
        $("a.greybox").click(function(){
          var t = this.title || $(this).text() || this.href;
          GB_show(t,this.href,470,600);
          return false;
        });
      });
    </script>

 

and my form button is...

 

<input type="image" src="images/buynow_bt.jpg" border="0" name="submit" width="100" height="25" alt="purchase">

 

I can see in my script (It's been taken from elsewhere) that It has links (a, href) and isnt written for a form button, Can anybody advise me on how to make this work with a form?