var cal;

function switchCalendar(month, year, room) {
  month = month || cal.month;
  year  = year  || cal.year;
  room  = room  || $('#roomNr').val();

  cal = new Calendar(month, year, room)
  var calHTML = cal.getWithButtons();
  $('#calendarContainer').empty().append(calHTML);
  return false;
}

var today = new Date();
switchCalendar(today.getMonth() + 1, today.getFullYear());