Esto resuelve eso que mencionás:
Código PHP:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title></title>
<script>
function getWindowData(n,i){
var ifr=document.getElementById(i).contentWindow.document || document.getElementById(i).contentDocument;
var widthViewport,heightViewport,xScroll,yScroll,widthTotal,heightTotal;
if (typeof window.frames[n].innerWidth != 'undefined'){
widthViewport= window.frames[n].innerWidth;
heightViewport= window.frames[n].innerHeight;
}else if(typeof ifr.documentElement != 'undefined' && typeof ifr.documentElement.clientWidth !='undefined' && ifr.documentElement.clientWidth != 0){
widthViewport=ifr.documentElement.clientWidth;
heightViewport=ifr.documentElement.clientHeight;
}else{
widthViewport= ifr.getElementsByTagName('body')[0].clientWidth;
heightViewport=ifr.getElementsByTagName('body')[0].clientHeight;
}
xScroll=window.frames[n].pageXOffset || (ifr.documentElement.scrollLeft+ifr.body.scrollLeft);
yScroll=window.frames[n].pageYOffset || (ifr.documentElement.scrollTop+ifr.body.scrollTop);
widthTotal=Math.max(ifr.documentElement.scrollWidth,ifr.body.scrollWidth,widthViewport);
heightTotal=Math.max(ifr.documentElement.scrollHeight,ifr.body.scrollHeight,heightViewport);
return [widthViewport,heightViewport,xScroll,yScroll,widthTotal,heightTotal];
}
function resizeIframe(ID,NOMBRE){
document.getElementById(ID).height=null;
document.getElementById(ID).width=null;
var m=getWindowData(NOMBRE,ID);
document.getElementById(ID).height=m[5];
document.getElementById(ID).width=m[4]+22;
}
</script>
</head>
<body>
<iframe name="menu" id="menu" src="test2.php" frameborder="1" scrolling="no" onload="resizeIframe('menu','menu');"></iframe></body>
</html>