if (document.images) {
  
  image1on = new Image();
  image1on.src = "nav1on.gif";
  image1 = new Image();
  image1.src = "nav1.gif";
  
  image2on = new Image();
  image2on.src = "nav2on.gif";
  image2 = new Image();
  image2.src = "nav2.gif";
  
  image3on = new Image();
  image3on.src = "nav3on.gif";
  image3 = new Image();
  image3.src = "nav3.gif";
  
  image4on = new Image();
  image4on.src = "nav4on.gif";
  image4 = new Image();
  image4.src = "nav4.gif";
  
  image5on = new Image();
  image5on.src = "nav5on.gif";
  image5 = new Image();
  image5.src = "nav5.gif";
  
  image6on = new Image();
  image6on.src = "nav6on.gif";
  image6 = new Image();
  image6.src = "nav6.gif";
  
  image7on = new Image();
  image7on.src = "nav7on.gif";
  image7 = new Image();
  image7.src = "nav7.gif";
  
  image8on = new Image();
  image8on.src = "nav8on.gif";
  image8 = new Image();
  image8.src = "nav8.gif";
}

function changeImages() {
  if (document.images) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = eval(changeImages.arguments[i+1] + ".src");
    }
  }
}