function showNavigationHelp() {
    $('navigationHelp').appear({duration: 0.4});
    $('navigationAbout').hide();
}

function showNavigationAbout() {
    $('navigationAbout').appear({duration: 0.4});
    $('navigationHelp').hide();
}

function hideSubNavigation() {
    $('navigationAbout').fade();
    $('navigationHelp').fade();
}

Event.observe(window, 'load', function() {
    Event.observe('about_nav', 'click', function() {
        showNavigationAbout();
    });
    Event.observe('help_nav', 'click', function() {
        showNavigationHelp();
    });
});