//Bilder vorladen
		var pfad="img/index/";
		var end=".gif";
			function preload() {
			var img1=new Image();
			img1.src= pfad+"1a"+end;
			var img2=new Image();
			img2.src= pfad+"1b"+end;
			var img3=new Image();
			img3.src= pfad+"2a"+end;
			var img4=new Image();
			img4.src= pfad+"2b"+end;
  			}
		
//Bilderwechsel
			la1 = new Image();
			la1.src = pfad+"1a"+end;
			la2 = new Image();
			la2.src = pfad+"1b"+end;
			la3 = new Image();
			la3.src = pfad+"2a"+end;
			la4 = new Image();
			la4.src = pfad+"2b"+end;
			
			function tausch(name,bild) {
					document.images[name].src = eval(bild+".src");
			}