if (document.images) {

  image1on = new Image();
  image1on.src = "images/menu1-on.gif";
  image2on = new Image();
  image2on.src = "images/menu2-on.gif";
  image3on = new Image();
  image3on.src = "images/menu3-on.gif";
  image4on = new Image();
  image4on.src = "images/menu4-on.gif";
  image5on = new Image();
  image5on.src = "images/menu5-on.gif";
  image6on = new Image();	
  image6on.src = "images/menu6-on.gif";
  image7on = new Image();
  image7on.src = "images/menu7-on.gif";
  image8on = new Image();
  image8on.src = "images/menu8-on.gif";
  image9on = new Image();
  image9on.src = "images/menu9-on.gif";

  image1off = new Image();
  image1off.src = "images/menu1.gif";
  image2off = new Image();
  image2off.src = "images/menu2.gif";
  image3off = new Image();
  image3off.src = "images/menu3-in.gif";
  image4off = new Image();
  image4off.src = "images/menu4.gif"; 
  image5off = new Image();
  image5off.src = "images/menu5.gif";
  image6off = new Image();	
  image6off.src = "images/menu6.gif";
  image7off = new Image();
  image7off.src = "images/menu7.gif";
  image8off = new Image();
  image8off.src = "images/menu8.gif"; 
  image9off = new Image();
  image9off.src = "images/menu9.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");
  }
}