Something

<html>
<head>
<script language="Javascript">
function checkRes(){
	sWidth = screen.width
	if (sWidth == 1280){
		styleZoom = '128%'
	}
	if (sWidth == 1024){
		styleZoom = '100%'
	}
	if (sWidth <= 640){
		styleZoom = '72%'
	}
	alert('Zooming to "'+styleZoom+'" because screen width is "'+sWidth+'"')	// debug
	// Only Internet Explorer supports document.body.style.zoom
	document.body.style.zoom = styleZoom
	return true
}
</script>
</head>

<body onLoad="checkRes(); return true;">

<p>m00 de c0w!</p>

</body>
</html>