Set default date to a past date

Set default date to a past date

Hey guys, I just discovered jquery ui and it seems pretty awesome.  I implemented a date picker, but I can't seem to set it's default date to a date in the past.  Essentially I'd like to use it as an age checker to insure the person is over 21 (the site has alcohol references) so I want the default date to be set 21 years from the current date.  The pasted code below limits the pull down year menu to dates of 1900 to 1989 (2010 - 21), but when the date picker appears, the date is set to 1900 not 1989.  How to I get it to default to 1989 instead of 1900.  I have tried adding defaultDate: -21 but it doesn't appear to like that and the documentation only mentions positive numbers for the default date.  Is it possible to set it in the past?  Thanks in advance.
  3. <script type="text/javascript">
  4. $(function() {
  5. $("#memberBirthdayView").datepicker({altField: '#memberBirthday', altFormat: 'yy-mm-dd', changeMonth: true, changeYear: true, yearRange: '-110:-21'});
  6. });
  7. </script>