function imgOn(imgName) {
   if (document.images) {
       document[imgName].src = eval(imgName + "on.src");
        }
}

function imgOff(imgName) {
        if (document.images) {
            document[imgName].src = eval(imgName + "off.src");
        }
}


img1on = new Image();
img1on.src = "img/kast.gif";
img2on = new Image();
img2on.src = "img/produkte.gif";
img3on = new Image();
img3on.src = "img/laden.gif";
img4on = new Image();
img4on.src = "img/zahlung.gif";
img5on = new Image();
img5on.src = "img/impressum.gif";


img1off = new Image();
img1off.src = "img/kast2.gif";
img2off = new Image();
img2off.src = "img/produkte2.gif";
img3off = new Image();
img3off.src = "img/laden2.gif";
img4off = new Image();
img4off.src = "img/zahlung2.gif";
img5off = new Image();
img5off.src = "img/impressum2.gif";