if (document.images) {

  home0     = new Image;
  home0.src = "../images/menu-home-0.gif"
  home1     = new Image;
  home1.src = "../images/menu-home-1.gif"

  intro0     = new Image;
  intro0.src = "../images/menu-intro-0.gif"
  intro1     = new Image;
  intro1.src = "../images/menu-intro-1.gif"

  depth0     = new Image;
  depth0.src = "../images/menu-depth-0.gif"
  depth1     = new Image;
  depth1.src = "../images/menu-depth-1.gif"

  demos0     = new Image;
  demos0.src = "../images/menu-demos-0.gif"
  demos1     = new Image;
  demos1.src = "../images/menu-demos-1.gif"

  links0     = new Image;
  links0.src = "../images/menu-links-0.gif"
  links1     = new Image;
  links1.src = "../images/menu-links-1.gif"

  sources0     = new Image;
  sources0.src = "../images/menu-sources-0.gif"
  sources1     = new Image;
  sources1.src = "../images/menu-sources-1.gif"

  glossary0     = new Image;
  glossary0.src = "../images/menu-glossary-0.gif"
  glossary1     = new Image;
  glossary1.src = "../images/menu-glossary-1.gif"

  mail0     = new Image;
  mail0.src = "../images/menu-mail-0.gif"
  mail1     = new Image;
  mail1.src = "../images/menu-mail-1.gif"

}

function on(img, txt) {
  if (document.images)
    document.images[img].src = eval(img + "1.src");
  window.status = txt;
}

function off(img) {
  if (document.images)
    document.images[img].src = eval(img + "0.src");
  window.status = ' ';
}