function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		unternehmen_over = newImage("images/unternehmen-over.gif");
		maschinen_over = newImage("images/maschinen-over.gif");
		dienstleistungen_over = newImage("images/dienstleistungen-over.gif");
		projekte_over = newImage("images/projekte-over.gif");
		karriere_over = newImage("images/karriere-over.gif");
		kontakt_over = newImage("images/kontakt-over.gif");	
		preloadFlag = true;
	}
}