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) {
		logo_over = newImage("gfx/logo-over.jpg");
		but_anf_over = newImage("gfx/but-anf-over.jpg");
		but_kon_over = newImage("gfx/but-kon-over.jpg");
		but_hp_over = newImage("gfx/but-hp-over.jpg");
		but_minus_over = newImage("gfx/but-minus-over.jpg");
		but_rel_over = newImage("gfx/but-rel-over.jpg");
		but_plus_over = newImage("gfx/but-plus-over.jpg");
		but_pfeil_re = newImage("gfx/pfeil-re-on.jpg");
		font_minus = newImage("gfx/font-minus.jpg");
		font_norm = newImage("gfx/font-norm.jpg");
		font_plus = newImage("gfx/font-plus.jpg");
		preloadFlag = true;
	}
}