if (document.images) {
image1on = new Image();
image1on.src = "images/top-1r.gif";
image1off = new Image();
image1off.src = "images/top-1b.gif";
} 
if (document.images) {
image2on = new Image();
image2on.src = "images/top-2r.gif";
image2off = new Image();
image2off.src = "images/top-2b.gif";
} 
if (document.images) {
image3on = new Image();
image3on.src = "images/top-3r.gif";
image3off = new Image();
image3off.src = "images/top-3b.gif";
} 
if (document.images) {
image4on = new Image();
image4on.src = "images/top-4r.gif";
image4off = new Image();
image4off.src = "images/top-4b.gif";
} 

function changeImages() {
if (document.images) {
for (var i=0; i<changeImages.arguments.length; i+=2) {
document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
}}}