Hi Friend,
Here's a simple solution using jQuery.
<!--
<script type="text/javascript" src="js/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
$("#nav li a").click(function(){
var link = "includes/" + $(this).text().toLowerCase() + ".php";
$("#container").load(link);
return false;
});
});
</script>
The above code will surely solve the problem. Just in case, it may need debugging 'cause I didn't test it right now.
Hope that it helps :)
With Regards
Tushar Srivastava