var topNav = new Array('Home','Products','Services','About','Contact');

function getSubMenu(topLevelMenu) {
   return document.getElementById(topLevelMenu+'SubMenu');
}

function navigateMenu(topLevelMenu) {
    for(var i=0; i < topNav.length; i++) {
        if(topLevelMenu == topNav[i]) {
            makeActive(topLevelMenu, true, i==0); 
        }
        else {
            makeActive(topNav[i], false);
        }
    }
}

function makeActive(menuName, isActive, isFirst) {
   var menuElement = document.getElementById(menuName);
   if (menuElement) { 
        menuElement.className=isActive ? ("active" + (isFirst ? " first " : "")) : "";
        show(getSubMenu(menuName), isActive); 
   }
}


function clearSubMenuSelection (activeTopLevelMenu) {
    var subMenu = getSubMenu(activeTopLevelMenu);
    if (subMenu) {
        var liItems = subMenu.getElementsByTagName("li"); 
        if (liItems) {
            for(var j=0; j < liItems.length; j++) {
                if (liItems[j]) liItems[j].className=""; 
            }
        }
    }
}

function show(element, isShow) {
    if (element)
       element.style.display = (isShow) ? "block" : "none";
}