calendar.js, lines 94,95 should be in reverse order,
because if month is set before day, there are no days
in month shown (default tmpdate has actual day of
month, but when actual day has 31 days, and month
before or month after - 30, function set bad month
number(and condition in while loop is not work properly)).
Set your system clock to: 31-Nov and try to switch to
month nr 2,6,9, or 11.
So good order is: