if (document.images) {
  image1on = new Image();
  image1on.src = "images/michael_02.jpg";

  image2on = new Image();
  image2on.src = "images/media_02.jpg";

  image3on = new Image();
  image3on.src = "images/forum_02.jpg";

  image4on = new Image();
  image4on.src = "images/gallery_02.jpg";

  image5on = new Image();
  image5on.src = "images/site_02.jpg";

  image6on = new Image();
  image6on.src = "images/online_02.jpg";



  image1off = new Image();
  image1off.src = "images/michael_01.jpg";

  image2off = new Image();
  image2off.src = "images/media_01.jpg";

  image3off = new Image();
  image3off.src = "images/forum_01.jpg";

  image4off = new Image();
  image4off.src = "images/gallery_01.jpg";

  image5off = new Image();
  image5off.src = "images/site_01.jpg";

  image6off = new Image();
  image6off.src = "images/online_01.jpg";


}

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");
  }
}