var first_off = "1off.jpg";
   var first_on = "1on.jpg";
   var second_off = "2off.jpg";
   var second_on = "2on.jpg";
   var third_off = "3off.jpg";
   var third_on = "3on.jpg";
   var fourth_off = "4off.jpg";
   var fourth_on = "4on.jpg";
   var fifth_off = "5off.jpg";
   var fifth_on = "5on.jpg";
   var sixth_off = "6off.jpg";
   var sixth_on = "6on.jpg";
   var seventh_off = "7off.jpg";
   var seventh_on = "7on.jpg";
   var eight_off = "8off.jpg";
   var eight_on = "8on.jpg";

   function activate(imgName) {
      document.images[imgName].src = eval(imgName + "_on");
   }

   function deactivate(imgName) {
      document.images[imgName].src = eval(imgName + "_off");
   }
   function loadstuff() {
       images = new Array(8)
	   for (var i = 1; i <= 8; i++) {
	   	  images[i] = new Image();
		  images[i].src = i + "on.jpg";
	   }
   }