var imgs = new Object();
  imgs.act = new Image();
  imgs.act.src = 'images/menu_act.gif';
  imgs.dis = new Image();
  imgs.dis.src = 'images/menu_dis.gif';

  function changeImage(id,img) {
   if (img == 0) post = 'dis'; else post = 'act';
   // document.images['login'].src=imgs.dis.src;
   // document.images['password'].src=imgs.dis.src;
   eval("document.images['" + id + "'].src=imgs." + post + ".src;");
  }