<script type="text/javascript">

var calendarHight;

function hideCalendar() {
    var calendarBox = document.getElementById('box-timetable');
    calendarBox.style.visibility = "hidden";
    calendarHight = calendarBox.style.height;
    calendarBox.style.height = "0px";
    var hideCalendarA = document.getElementById('hideCalendarA');
    hideCalendarA.href = 'javascript:showCalendar();';
}

function showCalendar() {
    var calendarBox = document.getElementById('box-timetable');
    calendarBox.style.visibility = "visible";
    calendarBox.style.height = calendarHight;
    var hideCalendarA = document.getElementById('hideCalendarA');
    hideCalendarA.href = 'javascript:hideCalendar();';
}
</script>