$(function() {
    var IdleTime = 0;
    var timeout;

    // initially fade in upon page load
    $('#header-wrapper').delay(100).fadeIn(1600);

    // They may be idle from this point onwards
    // We do a check to find out
    timeout = setTimeout("checkIdle()", 5000); // 5 seconds

    $(document).bind('mousemove', function() {
        // check if #header-wrapper is not visible
        if (!$('#header-wrapper').is(':visible'))
        {
            // Header is invisible, so fade in
            $('#header-wrapper').fadeIn(1600);

            // They may be idle from this point onwards
            // We do a check to find out
            timeout = setTimeout("checkIdle()", 5000); // 5 seconds
        }
    });

    function checkIdle()
    {
        clearTimeout(timeout);

        IdleTime += 5; // 5 seconds

        if (IdleTime >= 180) // 180 seconds = 3 minutes
        {
            // Reset idle time
            IdleTime = 0;

            // if header is visible
            if ($('#header-wrapper').is(':visible'))
            {
                // Header is visible, so fade out
                $('#header-wrapper').fadeOut(1600);
            }
        }
        else
        {
            // If the user is idle, why bother doing checks?
            // User is not idle to this point, so we check again
            timeout = setTimeout("checkIdle()", 5000); // 5 seconds
        }
    }
});