var timeout    = 500;
var closetimer = 0;
var ddmenuitem = 0;

function mopen(id) {   
  mcancelclosetime();
  if (ddmenuitem) ddmenuitem.style.visibility = 'hidden';
  ddmenuitem = document.getElementById(id);
  ddmenuitem.style.visibility = 'visible';
}
function mclose() {
  if (ddmenuitem) ddmenuitem.style.visibility = 'hidden';
}
function mclosetime() {
  closetimer = window.setTimeout(mclose,timeout);
}
function mcancelclosetime() {
  if (closetimer) {
    window.clearTimeout(closetimer);
    closetimer = null;
  }
}
//document.onclick = mclose;