var objCount = 0;
var pics = new Array();

function preload(name, first, second) { 
    pics[objCount] = new Array(3);
    pics[objCount][0] = new Image();
    pics[objCount][0].src = first;
    pics[objCount][1] = new Image();
    pics[objCount][1].src = second;
    pics[objCount][2] = name;
    objCount++;
}

function on(name){
     for (i = 0; i < objCount; i++) {
      if (document.images[pics[i][2]] != null)
        if (name != pics[i][2]) {
          document.images[pics[i][2]].src = pics[i][0].src;
        } else {
          document.images[pics[i][2]].src = pics[i][1].src;
        }
    }
}

function off(){
     for (i = 0; i < objCount; i++) {
      if (document.images[pics[i][2]] != null)
        document.images[pics[i][2]].src = pics[i][0].src;
    }
}

preload("L1", "source/b01.gif", "source/b11.gif");
preload("L2", "source/b02.gif", "source/b12.gif");
preload("L3", "source/b03.gif", "source/b13.gif");
preload("L4", "source/b04.gif", "source/b14.gif");
preload("L5", "source/b05.gif", "source/b15.gif");
preload("L6", "source/b06.gif", "source/b16.gif");
preload("L7", "source/b07.gif", "source/b17.gif");
preload("L8", "source/b08.gif", "source/b18.gif");
preload("L9", "source/b09.gif", "source/b19.gif");
preload("L9g", "source/b09g.gif", "source/b19g.gif");