if(document.images){
	        ccovera = new Image;
                ccoverb = new Image;
		ccouta  = new Image;
                ccoutb  = new Image;
		ccovera.src = "img/kegelsymN.gif";
		ccouta.src  = "img/kegelsym.gif";
                ccoverb.src = "img/kegelbN.jpg";
		ccoutb.src  = "img/kegelb.jpg";
		}

	 function ccOna(img) {
	    if (document.images) document.images[img].src=ccovera.src;}	

	 function ccOffa(img) {
	    if (document.images) document.images[img].src=ccouta.src;}		
    

	 function ccOnb(img) {
	    if (document.images) document.images[img].src=ccoverb.src;}	

	 function ccOffb(img) {
	    if (document.images) document.images[img].src=ccoutb.src;}