function doPreload()  {
   var the_images = new Array(
   "images/heights_floorplans2a-on.html", 
   "images/heights_floorplans2b1-on.html", 
   "images/heights_floorplans2c-on.html", 
   "images/heights_floorplans2b2-on.html", 
   "images/heights_floorplans2d-on.html",
   "images/heights_floorplans3-5a-on.html", 
   "images/heights_floorplans3-5b1-on.html", 
   "images/heights_floorplans3-5c-on.html", 
   "images/heights_floorplans3-5b3-5-on.html", 
   "images/heights_floorplans3-5d-on.html")
      
   preloadImages(the_images);
}

function preloadImages(theImages)  {
   for(i = 0; i < theImages.length; i++)  {
      var theImage = new Image();
      theImage.src = theImages[i];
   }
}