Ok, so in Javascript (not jQuery or anything):
<html>
<head>
<script type="text/javascript">
<!--
var sWidth;
var sHeight;
if (typeof window.innerWidth != 'undefined')
{
sWidth = window.innerWidth,
sHeight = window.innerHeight
} else if (typeof document.documentElement != 'undefined'
&& typeof document.documentElement.clientWidth !=
'undefined' && document.documentElement.clientWidth != 0)
{
sWidth = document.documentElement.clientWidth,
sHeight = document.documentElement.clientHeight
} else
{
sWidth = document.getElementsByTagName('body')[0].clientWidth,
sHeight = document.getElementsByTagName('body')[0].clientHeight
}
//VARIABLES STORED IN sWidth AND sHeight
document.write('<div style="height: '+sHeight+'; width: '+sWidth+';">CONTENT</div>');
//-->
</script>
</head>
<body>
</body>
</html>
Obviously you could write the div out seperately ^_^