var uCurrentMenuItemId = 0;

function onMenuLoad (Id)
{
    document.getElementById (Id).className = "menu_item";
}

function onMenuHover (Id, State)
{
    var e = document.getElementById (Id);

    if (Id == uCurrentMenuItemId)
    {
        e.className = "menu_item2";
    }
    else
    {
        if (State == 0)
        {
            e.className = "menu_item";
        }
        else
        {
            e.className = "menu_item_hover";
        }
    }
}

function GetPageName (Id)
{
    switch (Id)
    {
        case 1:
            return "index";
        case 2:
            return "screens";
        case 3:
            return "download";
        case 4:
            return "faq";
        case 5:
            return "support";
    }

    return null;
}

function UpdateMenuItem(Id)
{
    if (uCurrentMenuItemId == Id)
    {
        return;
    }

    if (uCurrentMenuItemId != 0)
    {
        document.getElementById (uCurrentMenuItemId).className = "menu_item";
    }

    document.getElementById (Id).className = "menu_item2";

    uCurrentMenuItemId = Id;
}

function onMenuItem (Id)
{
    window.location.assign (GetPageName (Id) + ".html");
}

function GetArgs ()
{
    if (document.location.href.indexOf ("?") == -1)
    {
        return null;
    }

    return document.location.search.substr (1).split ("&");
}

function GetArg (ArgName)
{
    var args = GetArgs ();
    if (args == null) return null;

    for (var i in args)
    {
        var a = args [i].split ("=");
        if (a.length != 2) continue;

        if (a [0] == ArgName)
        {
            return a [1];
        }
    }

    return null;
}

function onLoad (Id)
{
    for (var i = 1; i <= 5; i++)
    {
        if (Id != i)
        {
            onMenuLoad (i);
        }
    }

    UpdateMenuItem (Id);
}