jQuery UI datepicker not showing week numbers

My jquery UI datepicker is not showing week numbers, even with the showWeek:true option set. Here is my code:

<script type='text/javascript'>
  $(document).ready(function(){
    $('#startDate').datepicker({ 
      changeMonth: true, 
    开发者_运维技巧  changeYear:true, 
      dateFormat: 'd-M-yy', 
      firstDay: 1, 
      showButtonPanel: true, 
      showWeek: true 
  });
});
</script>
<input type='text' name='startDate' id='startDate'>

From what I understand, you ONLY need to set the showWeek option to make this work - the weekHeading has a default of 'Wk' and the calculateWeekNumber has a built in ISO week number calculator function.

Also, for some reason the 'Today' button on the button panel is disabled?! Any advice would be most appreciated. Thanks.

I think you might be using jQueryUI v1.7.2. You need v1.8 to get the showWeek option. I have v1.8rc3 and it works well.

demo: http://jsbin.com/eliki