// Zum Testen im onLoad
//alert('getheightofdoc=' + getheightofdoc() + ' getheightofdisplay=' + getheightofdisplay());

function needtoshowbacktop() {	
	if (self.screen.availHeight < getheightofdoc ()) {
		if ( getheightofdisplay() <= getheightofdoc () ) {
			document.getElementById("backToTopBox").style.display = "";
		}
	}
}