var selectedTab = null;
var currentTab = null;
var currentMenu = null;
var timeoutId = 0;

function showDropdown( tabId, menuId )
{
    clearTimeout( timeoutId );
    if ( !selectedTab && typeof( selectedTabId ) != "undefined" ) selectedTab = document.getElementById( selectedTabId );
    var tab = document.getElementById( tabId );
    var menu = document.getElementById( menuId );
    if ( tab != currentTab ) {
        if ( currentTab && currentTab != selectedTab ) currentTab.className = "nav-dropdown-tab";
        currentTab = tab;
        currentTab.className = "nav-dropdown-tab-selected";
        if ( currentMenu ) currentMenu.style.visibility = "hidden";
        if ( menu ) {
            currentMenu = menu;
            currentMenu.style.visibility = "visible";
        } else {
            currentMenu = null; 
        }
    }
}

function hideDropdown( tabId, menuId )
{
    timeoutId = setTimeout( 'hideDropdownTimeout( "' + tabId + '","' + menuId + '" )', 500 );
}

function hideDropdownTimeout( tabId, menuId )
{
    if ( !selectedTab && typeof( selectedTabId ) != "undefined" ) selectedTab = document.getElementById( selectedTabId );
    var tab = document.getElementById( tabId );
    var menu = document.getElementById( menuId );
    if ( tab != selectedTab ) tab.className = "nav-dropdown-tab";
    if ( menu ) menu.style.visibility = "hidden";
    currentTab = null;
    currentMenu = null;
}

function showItemHighlight( menuItem )
{
    menuItem.className = "nav-dropdown-item-highlight";
}

function hideItemHighlight( menuItem )
{
    menuItem.className = "nav-dropdown-item";
}