Hi Waghmare,
I have created sample code which fulfill your requirement.
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript">
function setUrl(url, target) {
clearTimeout(window.ht);
window.ht = setTimeout(function () {
var div = document.getElementById(target);
div.innerHTML = '<iframe style="width:100%;height:100%;" frameborder="1" src="' + url + '" />';
}, 50);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="#" onclick="setUrl('http://www.aspforums.net','div1')">Aspforums</a>
<br />
<a href="#" onclick="setUrl('http://www.aspsnippets.com','div1')">AspSnippets</a>
<br />
<br />
<br />
<div>
<div id="div1" style="width: 500px; height: 300px; border: 1px solid #ddd;">
</div>
</div>
</div>
</form>
</body>
</html>
Demo
