function hidedd(dd) {
 var menu = document.getElementById(dd);
 if (menu == null) return false;
 menu.style.visibility = 'hidden';
 menu.style.display = 'none';
 return true;
}

function showdd(dd) {
 var menu = document.getElementById(dd);
 if (menu == null) return false;
 menu.style.visibility = 'visible';
 menu.style.display = 'block';
 return true;
}