var dropdownmenuitem = 0;
var menuclosetimer = 0;
var timeout = 500;

function menuopen(id) {
  menucancelclosetime();
  //close old Menu Item
  if (dropdownmenuitem) dropdownmenuitem.style.visibility = 'hidden';
  //make the new Menu Item visible
  dropdownmenuitem = document.getElementById(id);
  dropdownmenuitem.style.visibility = 'visible';
}

function menuclose() {
  if (dropdownmenuitem) dropdownmenuitem.style.visibility = 'hidden';
}

function menuclosetime() {
  menuclosetimer = window.setTimeout(menuclose, timeout);
}

function menucancelclosetime() {
  if (menuclosetimer) {
    window.clearTimeout(menuclosetimer);
    menuclosetimer = null;
  }
}

document.onclick = menuclose;