function activateTime() {
    if (document.g_calendar.all.checked)
    {
        document.g_calendar.s_hour.disabled = true;
        document.g_calendar.s_min.disabled = true;
        document.g_calendar.e_hour.disabled = true;
        document.g_calendar.e_min.disabled = true;
    }
    else
    {
        document.g_calendar.s_hour.disabled = false;
        document.g_calendar.s_min.disabled = false;
        document.g_calendar.e_hour.disabled = false;
        document.g_calendar.e_min.disabled = false;
    }
}