if (document.images) {

  abouton = new Image();
  abouton.src = "nav/about_on.gif";
  aboutoff = new Image();
  aboutoff.src = "nav/about_off.gif";

  hostingon = new Image();
  hostingon.src = "nav/hosting_on.gif";
  hostingoff = new Image();
  hostingoff.src = "nav/hosting_off.gif";

  supporton = new Image();
  supporton.src = "nav/support_on.gif";
  supportoff = new Image();
  supportoff.src = "nav/support_off.gif";

  contacton = new Image();
  contacton.src = "nav/contact_on.gif";
  contactoff = new Image();
  contactoff.src = "nav/contact_off.gif";

  homeon = new Image();
  homeon.src = "nav/home_on.gif";
  homeoff = new Image();
  homeoff.src = "nav/home_off.gif";
}

function turnOn(imageName) {
  if (document.images) {
    document[imageName].src =
      eval(imageName + 'on.src');
  }
}

function turnOff(imageName) {
  if (document.images) {
    document[imageName].src =
      eval(imageName + 'off.src');
  }
}