function preload_images()
{
  image1on = new Image();
  image1on.src = "/images/left_on.gif";

  image2on = new Image();
  image2on.src = "/images/right_on.gif";

  image3on = new Image();
  image3on.src = "/images/news_on.gif";

  image4on = new Image();
  image4on.src = "/images/links_on.gif";

  image5on = new Image();
  image5on.src = "/images/gallery_on.gif";

  image6on = new Image();
  image6on.src = "/images/articles_on.gif";

  image7on = new Image();
  image7on.src = "/images/about_on.gif";

  image8on = new Image();
  image8on.src = "/images/blank_on.gif";
  
  image1off = new Image();
  image1off.src = "/images/left_off.gif";

  image2off = new Image();
  image2off.src = "/images/right_off.gif";

  image3off = new Image();
  image3off.src = "/images/news_off.gif";

  image4off = new Image();
  image4off.src = "/images/links_off.gif";

  image5off = new Image();
  image5off.src = "/images/gallery_off.gif";

  image6off = new Image();
  image6off.src = "/images/articles_off.gif";

  image7off = new Image();
  image7off.src = "/images/about_off.gif";

  image8off = new Image();
  image8off.src = "/images/blank_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");
  }
}