Hi,
check this code once
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script src="Scripts/jquery-1.4.1.js" type="text/javascript"></script>
<script src="Scripts/jquery-1.4.1-vsdoc.js" type="text/javascript"></script>
<script language ="javascript" >
$(document).ready(function (evt) {
$("#popupdiv").hide();
});
function showdiv(tid,asd) {
$("#popupcontent").html("Your message is :" + asd)
$("#popupdiv").css("position", "fixed");
$("#popupdiv").css("left", "150px");
$("#popupdiv").css("top", "150px");
$("#popupdiv").show();
}
function closepopup() {
$("#popupdiv").hide();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<a href="#" onclick="showdiv(this,'frst')">this is first</a><br />
<a href="#" onclick="showdiv(this,'second')">this is second</a><br /><br /><br /><br /><br /><br />
<a href="#" onclick="showdiv(this,'third')">this is thrid</a><br /><br /><br /><br /><br /><br /><br /><br />
<a href="#" onclick="showdiv(this,'fourth')">this is fourth</a><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br />
</div>
<div id="popupdiv" style=" width :200px; height :200px; background-color :Red ;">
<div id="popupcontent"></div>
this is popup div<br />
<a href="#" onclick="closepopup()">close</a>
</div>
</form>
</body>
</html>
All the Best