I faced this same problem and this is what I found that worked for me.
A frame is basically a window object. All the rules about windows apply to frames. A div belongs to a document which is held inside a window. Since the document can't leave its window, the div can't leave its window. You're asking for control at the level of the browser, but all you are permitted is control at the level of the document.
However, you may do a DIV over an iframe but not a frameset.
UPDATE:
Take this example my friend, It took some time for me to solve it, but really , StackOverflow has helped me a lot, so I feel that I must put this example here to help others.
This the html of page-container, it contains an iframe that will request the page-frameset that you are wanting to overlay.
<head>
<style type="text/css">
html, body#mybcontainer_body{margin:0px;padding:0px;border:none;height:100%;width:100%;}
#mybcontainer_div{position:absolute;top:0px;bottom:0px;left:0px;right:0px;}
#mybcontainer_iframe{position:absolute;top:0%;left:0%;height:100%;width:100%;}
</style>
</head>
<body id="mybcontainer_body" >
<div id="mybcontainer_dialog" style="display:none;">Some Text Here</div>
<div id="mybcontainer_div"><iframe id="mybcontainer_iframe" border="0" frameborder="0" scrolling="no" noresize="noresize" src="page-two-contain-frameset"></iframe></div>
</body>
My Regards