function PreloadImages(length, path, type) {
for (var i = 1; i <= length; i++) {
this[i] = new Image();
this[i].src = path + i + type;
}
return this;
}

over = new PreloadImages(8,'images/over','.gif');
norm = new PreloadImages(8,'images/norm','.gif');

function rollOn(num){
if (document.images)
eval('document.images["norm' + num + '"].src=' + 'over[num].src');
}
function rolloff(num){
if (document.images)
eval('document.images["norm' + num + '"].src=' + 'norm[num].src');
}