var dftmenuid='';
var lastmenuid='';
var menutimerid='';

function setmenutimer() {menutimerid=setTimeout('hidemenu()',500);}
function zapmenutimer() {if(menutimerid) clearTimeout(menutimerid);}

function setvis(menuid,vis) {
  if(menuid) {
    var v = document.getElementById(menuid + '2');
    if(v) v.style.visibility = vis;
    var vo = document.getElementById(menuid + 'o');
    if(vo) vo.className=(vis=='visible'?'navo_active':'navo');
  }
}

function showmenu(menuid) {
  zapmenutimer();
  setvis(lastmenuid,'hidden');
  setvis(menuid,'visible');
  lastmenuid=menuid;
}

function hidemenu() {showmenu(dftmenuid);}