browserName = navigator.appName;
  browserVer = parseInt(navigator.appVersion);
  canWork = "TRUE"
  if (browserName == "Netscape" && browserVer >= 3)  canWork = "TRUE";
  if (browserName == "Microsoft" && browserVer >= 4)  canWork = "TRUE";

  if (canWork == "TRUE")  {
    bioOn = new Image();
    bioOn.src = "/home-images/nav_bio_b.gif";
    bioOff = new Image();
    bioOff.src = "/home-images/nav_bio.gif";
    classOn = new Image();
    classOn.src = "/home-images/nav_class_b.gif";
    classOff = new Image();
    classOff.src = "/home-images/nav_class.gif";
    contactOn = new Image();
    contactOn.src = "/home-images/nav_contact_b.gif";
    contactOff = new Image();
    contactOff.src = "/home-images/nav_contact.gif";
    galleryOn = new Image();
    galleryOn.src = "/home-images/nav_gallery_b.gif";
    galleryOff = new Image();
    galleryOff.src = "/home-images/nav_gallery.gif";
    homeOn = new Image();
    homeOn.src = "/home-images/nav_home_b.gif";
    homeOff = new Image();
    homeOff.src = "/home-images/nav_home.gif";
    productsOn = new Image();
    productsOn.src = "/home-images/nav_products_b.gif";
    productsOff = new Image();
    productsOff.src = "/home-images/nav_products.gif";
    shopOn = new Image();
    shopOn.src = "/home-images/nav_shop_b.gif";
    shopOff = new Image();
    shopOff.src = "/home-images/nav_shop.gif";
    ideasOn = new Image();
    ideasOn.src = "/home-images/nav_ideas_b.gif";
    ideasOff = new Image();
    ideasOff.src = "/home-images/nav_ideas.gif";
  }

  function imageOn(imgName) {
    if (canWork == "TRUE")  {
      newimg = eval(imgName + "On.src");
      document[imgName].src = newimg;
    }
  }
  
  function imageOff(imgName) {
    if (canWork == "TRUE")  {
      newimg = eval(imgName + "Off.src");
      document[imgName].src = newimg;
    }
  }