menuOver = function() {
  var itensMenu = document.getElementById("boxMenu").getElementsByTagName("li");

  for (var i = 0; i < itensMenu.length; i++) {
    itensMenu[i].onmouseover = function() {
      this.className += " over";
    }
    itensMenu[i].onmouseout = function() {
      this.className = this.className.replace(new RegExp(" over\\b"), "");
    }
  }
}
if (window.attachEvent) window.attachEvent("onload", menuOver);