if (document.images) {            
      
      img1on = new Image();	img1on.src = "imgs/led1on.gif";
      img1off = new Image();	img1off.src = "imgs/led1off.gif"; 

      img2on = new Image();	img2on.src = "imgs/led2on.gif";
      img2off = new Image();	img2off.src = "imgs/led2off.gif";

      img3on = new Image();	img3on.src = img2on.src;
      img3off = new Image();	img3off.src = img2off.src;

      img4on = new Image();	img4on.src = img3on.src;
      img4off = new Image();	img4off.src = img3off.src

      img5on = new Image();	img5on.src = img3on.src;
      img5off = new Image();	img5off.src = img3off.src
      
      img6on = new Image();	img6on.src = img3on.src;
      img6off = new Image();	img6off.src = img3off.src

      img7on = new Image();	img7on.src = img3on.src;
      img7off = new Image();	img7off.src = img3off.src

      img8on = new Image();	img8on.src = img3on.src;
      img8off = new Image();	img8off.src = img3off.src

      img9on = new Image();	img9on.src = img3on.src;
      img9off = new Image();	img9off.src = img3off.src

      img10on = new Image();	img10on.src = img3on.src;
      img10off = new Image();	img10off.src = img3off.src
      
      img11on = new Image();	img11on.src = img3on.src;
      img11off = new Image();	img11off.src = img3off.src
   }

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");
   }
}