TimohaP,
<!DOCTYPE html>
<html>
<head>
<title></title>
<script type="text/javascript">
function get(a) {
var d = document,
b = d.body,
e = d.documentElement,
c = "client" + a;
a = "scroll" + a;
return d.compatMode === "CSS1Compat" ? Math.max(e[c], e[a]) : Math.max(b[c], b[a])
};
window.onload = function() {
alert([get('Width'),get('Height')]);
}
</script>
</head>
<body>
</body>
</html>