function menuHover() {
  
    var listItems = document.getElementById("menu-list").getElementsByTagName('li');   
    for(var i = 0; i < listItems.length; i++) {   
        listItems[i].onmouseover = function() {   
            this.className += 'menuBackgroundOver';   
        }   
        listItems[i].onmouseout = function() {   
            this.className = this.className.replace('menuBackgroundOver', '');   
        }   
    }   
}