if (document.images) {

          img1on = new Image(220,44);
          img1on.src = "gif/armyon.gif";

          img2on = new Image(220,44);
          img2on.src = "gif/navyon.gif";

          img3on = new Image(220,44);
          img3on.src = "gif/airforceon.gif";

          img4on = new Image(220,44);
          img4on.src = "gif/marineon.gif";

          img5on = new Image(220,44);
          img5on.src = "gif/coaston.gif";

          img6on = new Image(220,44);
          img6on.src = "gif/newon.gif";

          img7on = new Image(102,44);
          img7on.src = "gif/unon.gif";

          img1off = new Image(220,44);
          img1off.src = "gif/armyoff.gif";

          img2off = new Image(220,44);
          img2off.src = "gif/navyoff.gif";

          img3off = new Image(220,44);
          img3off.src = "gif/airforceoff.gif";

          img4off = new Image(220,44);
          img4off.src = "gif/marineoff.gif";

          img5off = new Image(220,44);
          img5off.src = "gif/coastoff.gif";

          img6off = new Image(220,44);
          img6off.src = "gif/newoff.gif";

          img7off = new Image(102,44);
          img7off.src = "gif/unoff.gif";

     }

     function imgOn(imgName) {
          if (document.images) {
          document[imgName].src = eval(imgName + "on.src");
     }
}

     function imgOff(imgName) {
          if (document.images) {
               document[imgName].src = eval(imgName + "off.src");
     }
}