var currTimeout = new Array();
currTimeout["mnu_home"] = null;
currTimeout["mnu_office"] = null;
currTimeout["mnu_contact"] = null;

function showMenu(mnu) {
  if(currTimeout[mnu] != null)
    stopHide(mnu);
  var obj = document.getElementById(mnu);
  obj.style.visibility = "visible";
}

function hideMenu(mnu) {
  if(currTimeout[mnu] == null) {
    currTimeout[mnu] = window.setTimeout("realhideMenu('" + mnu + "');", 500);
  }
}

function realhideMenu(mnu) {
  var obj = document.getElementById(mnu);
  obj.style.visibility = "hidden";
  window.clearTimeout(currTimeout[mnu]);
  currTimeout[mnu] = null;
}

function stopHide(mnu) {
  window.clearTimeout(currTimeout[mnu]);
  currTimeout[mnu] = null;
}