function disorhide(id){
   path = "http://nuhs.swiiit.url3.net/wbn/slot/u388/";
   elem = document.getElementById(id);
   img = document.getElementById(id+'_img');
   if(elem.style.display==""||elem.style.display=="block"){
      elem.style.display="none";
      img.src=path+"plus.gif";
      }
   else if(elem.style.display=="none"){
      elem.style.display="block";
      img.src=path+"minus.gif";
      }
}