I used your demo.
The code use the page multiple-files-upload.aspx as a source for the iframe.
just add a web page test.aspx and copy paste to the body this code:
<html xmlns="
http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div><input type="button" value="hide" onclick="javacript:hide();" /></div>
<div id="div1" >
frame 1<br />
<iframe src="multiple-files-upload.aspx" height="300px" width="500px"></iframe>
</div>
<script type="text/javascript">
function hide()
{
var d1 = document.getElementById('div1');
if(d1.style.display == '')
{ d1.style.display = 'none';}
else
{d1.style.display = '';}
}
</script>
</form>
</body>
</html>
tirza