Originariamente inviato da Zero
Mmmm.. potresti provare con una soluzione javascript:

codice:
<html>
<head>
<title>Test</title>
<script>
function test(){
var s_width ='';
var s_height ='';
s_width=screen.width
s_height=screen.height

if (s_width == "640"){
 document.getElementById("tuodiv").style.display="none";
}

if (s_width == "800"){
 document.getElementById("tuodiv").style.display="none";
}

if (s_width == "1024"){
document.getElementById("tuodiv").style.display="block";
}

if (s_width == "1280"){
 document.getElementById("tuodiv").style.display="block";
} 
}
</script>
</head>

<body onload="test();">
<div id="tuodiv" style="width:200px;height:200px;border:1px solid #000;display:none;"></div>
</body>
</html>
forse cosi' potrebbe andare, ma il div scende insieme alla pagina quando scrollo.
Ho gia' il codice, come lo incorporo?
codice:
<script language="JavaScript" type="text/javascript">
<!--
function setVariables(){
	px="+'px'";
	if (navigator.appName == "Netscape") {
		if (parseInt(navigator.appVersion) >= 5){
			v=".top=";
			h=".left=";
			dS="document.getElementById(\"";
			sD="\").style";
			y="window.pageYOffset";
			x="window.pageXOffset";
		}
		else {
			v=".top=";
			h=".left=";
			dS="document.";
			sD="";
			y="window.pageYOffset";
			x="window.pageXOffset";
			px="";
		}
	}
	else {
		var validDoc=(document.compatMode && document.compatMode != "BackCompat")?1:0;
		h=".left=";
		v=".top=";
		dS="";
		sD=".style";
		y=(validDoc)?"document.documentElement.scrollTop":"document.body.scrollTop";
		x=(validDoc)?"document.documentElement.scrollLeft":"document.body.scrollLeft";
	}
	checkLocationA()
}

 movex=0,movey=0,xdiff=0,ydiff=0,ystart=0
,xstart=0

function checkLocation(){
	object="object1";
	yy=eval(y);
	xx=eval(x);
	ydiff=ystart-yy;
	xdiff=xstart-xx;
	if ((ydiff<(-1))||(ydiff>(1))) movey=Math.round(ydiff/10),ystart-=movey
	if ((xdiff<(-1))||(xdiff>(1))) movex=Math.round(xdiff/10),xstart-=movex
	if (ystart>=83){
		eval(dS+object+sD+v+(ystart+10)+px);
	} else {
		eval(dS+object+sD+v+83+px);
	}

	eval(dS+object+sD+h+xstart+px);
	setTimeout("checkLocation()",10);
}

function checkLocationA(){
	ystart=eval(y);
	xstart=eval(x);
}

//-->
</script>