Calculate Week in DatePicker

Calculate Week in DatePicker

Is there any examples on how to return the week number of the selected date in DatePicker into a textbox?

I've tried calculateWeek, but there doesn't seem to be much documentation to get it working.

  1. $('#datepicker').datepicker({
  2.     changeMonth: true,
  3.     changeYear: true,
  4.     showOtherMonths: true,
  5.     selectOtherMonths: true,
  6.     showWeek: true,
  7.     dateFormat: 'yy',
  8.     calculateWeek: myWeekCalc,
  9.     firstDay: 1
  10. });
Ideally I would like to return a formated date like yy-ww e.g. 2010-47

Many Thanks