function img(imgName,gbr1,gbr2)
{
  if (document.images)
   {
 	 nameon = imgName;
     nameon= new Image();
     nameon.src=gbr1;
	 
	 nameoff = imgName;
     nameoff= new Image();
     nameoff.src=gbr2;
   }
}

function lightup(imgName,g1,g2)
 {
   if (document.images)
    {
	  img(imgName,g1,g2);
      //imgOn=eval(imgName + "on.src");
      document[imgName].src= nameon.src;
    }
 }

function turnoff(imgName,g1,g2)
 {
   if (document.images)
    {
	  img(imgName,g1,g2);
      //imgOff=eval(imgName + "off.src");
      document[imgName].src= nameoff.src;
    }
 }