function newImage(arg) {
 if (document.images) {
  rslt = new Image();
  rslt.src = arg;
  return rslt;
 }
}
function changeImages() {
 if (document.images && (preloadFlag == true)) {
  for (var i=0; i<changeImages.arguments.length; i+=2) {
   document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
  }
 }
}
var preloadFlag = false;

function  preloadImages() {
 if (document.images) {
  topp1_over = newImage("/images/topp1-over.jpg");
  topp2_over = newImage("/images/topp2-over.jpg");
  topp3_over = newImage("/images/topp3-over.jpg");
  topp4_over = newImage("/images/topp4-over.jpg");
  topp5_over = newImage("/images/topp5-over.jpg");
  topp6_over = newImage("/images/topp6-over.jpg");
  preloadFlag = true;
 }
}