var menu = document.getElementById("Navigation").getElementsByTagName("ul");
  for (i=0;i<menu.length;i++) {
    menu[i].setAttribute("id","Navigation"+i)
    if (menu[i].parentNode.nodeName == "LI") {
      menu[i].parentNode.onmouseover = function () {
        this.lastChild.style.display = "block";
      }
      menu[i].parentNode.onmouseout = function () {
        this.lastChild.style.display = "none";
      }
    }
  }