function hidemenu(elmnt)
{
   var temstr = elmnt;
   if (document.getElementById(temstr))
      document.getElementById(temstr).style.display="none";
}
function showmenu(elmnt)
{
   var temstr = elmnt;
   var oldstr = document.getElementById('campo').value;
   if (document.getElementById(temstr)){
        document.getElementById(temstr).style.display="block";
   	document.getElementById('campo').value = temstr;
   }
   if ((temstr != oldstr) && (oldstr != ''))
      hidemenu(oldstr);
}