I can't get my sample rounded corners code to work

I can't get my sample rounded corners code to work

Can someone please tell me what I am missing in my code? It's susposed to display rounded rectangle but only displays the text.

Thanks...

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
  <TITLE> New Document </TITLE>
<script type="text/javascript" src="jquery-1.2.6.js"></script>
<script type="text/javascript" src="jquery.corner.js"></script>

<script type="text/javascript">
$(document).ready(function(){

$("div.box").corner();

});
</script>

</HEAD>

<BODY>

<div id="box1" class="box">
this would be the content
</div>

</BODY>
</HTML>