// preload images

   imageAn = new Image();
   imageAn.src = "/components/images/nav1A_on.gif";

   imageBn = new Image();
   imageBn.src = "/components/images/nav1B_on.gif";

   imageCn = new Image();
   imageCn.src = "/components/images/nav1C_on.gif";

   imageDn = new Image();
   imageDn.src = "/components/images/nav1D_on.gif";

   imageEn = new Image();
   imageEn.src = "/components/images/nav1E_on.gif";

   imageFn = new Image();
   imageFn.src = "/components/images/nav1F_on.gif";

   imageGn = new Image();
   imageGn.src = "/components/images/nav1G_on.gif";

   imageHn = new Image();
   imageHn.src = "/components/images/nav1H_on.gif";