@ammaryameen,
There are many different ways you can do this. You can use ajax to fetch content, or you can just use javascript to modify the css of a hidden element. Here's a simple example with a hidden element and a link that will show it.
Code:<a onclick="document.getElementById('elementId').style.display = '';" style="cursor:pointer;">show</a>
<div id="elementId" style="display:none;">
hidden content
</div>
If you need it to toggle (show
and hide) then you can set it back to "display:none".
You may also find javascript libraries like YUI, jquery, and mootools useful for this kind of thing if you end up doing more of it on your site.