function setScreenHeight () {
	var sh = "100%";
	if (document.body.clientHeight) {
		if (document.body.clientHeight <= 640) {
			sh = "640px";
		}
	} else {
		if (innerHeight <= 640) {
			sh = "640px";
		}
	}
	document.getElementById ("so").style.height = sh;
}

//document.getElementsByTagName ("body")[0].onload = setScreenHeight;
//document.getElementsByTagName ("body")[0].onresize = setScreenHeight;