Try this example:
http://forums.asp.net/t/1291323.aspx
<script language=”javascript”>
function showDiv()
{
var div = document.getElementById(‘myDiv’);
div.style.position = “absolute”;
div.style.visibility = “visible”;
div.style.display = “block”;
div.top = “50″;
div.left = “50″;
}
function closeDiv()
{
var div = document.getElementById(‘myDiv’);
div.style.visibility = “hidden”;
div.style.display = “none”;
}
</script>
<div id=”myDiv” style=”display:none;Visibility:hidden; width:100px; height:150px” >
any text here
<input type=”button” value=”Close” onclick=”closeDiv()” />
</div>
<span style=”color:blue; cursor:pointer” onclick=”showDiv()” ><u>Click</u></span>
Good Luck