for(i = 4; i <= 18; i++) {
	val = i > 9 ? i : "0"+i;
	pr[i] = new Image();
	pr[i].src = "/images/preisrechner/"+val+".gif";
	upr[i] = new Image();
	upr[i].src = "/images/preisrechner/u"+val+".gif";
}

function prech(val) {
	for(i = 4; i <= 18; i++) {
		x = i > 9 ? i : "0"+i;
		if(i <= val) {
			document.getElementById("a"+i).src = "/images/preisrechner/"+x+".gif";
			document.getElementById("b"+i).src = "/images/preisrechner/"+x+".gif";
			document.getElementById("c"+i).src = "/images/preisrechner/"+x+".gif";
			document.getElementById("d"+i).src = "/images/preisrechner/"+x+".gif";
			document.getElementById("e"+i).src = "/images/preisrechner/"+x+".gif";
			document.getElementById("u"+i).src = "/images/preisrechner/u"+x+".gif";
		}
		else {
			document.getElementById("a"+i).src = "/images/preisrechner/g"+x+".gif";				
			document.getElementById("b"+i).src = "/images/preisrechner/g"+x+".gif";				
			document.getElementById("c"+i).src = "/images/preisrechner/g"+x+".gif";				
			document.getElementById("d"+i).src = "/images/preisrechner/g"+x+".gif";				
			document.getElementById("e"+i).src = "/images/preisrechner/g"+x+".gif";				
			document.getElementById("u"+i).src = "/images/preisrechner/gu"+x+".gif";				
		}
	}
}