title: Changing minDate option in JQuery DatePicker does nothing
body: <p>I have this jQuery datepicker code that initially set the minDate of the datepicker. After a user selects a starting date, I used the option attribute to change the minDate of the datepicker, but nothing happens. What did I do wrong and how should I make it work?</p>
  
  <p><strong>Datepicker init code:</strong></p>
  
  <pre><code>$(function () {
      $('#starttime,#endtime,#validity').datepicker({
                  numberOfMonths: [1, 2],
                  buttonImageOnly: true,
                  showAnim: 'slideDown',
                  buttonImage: '../images/cal.gif',
                  beforeShow: customRange,
                  dateFormat: "dd-mm-yy",
                  firstDay: 1,
                  changeFirstDay: false
      });
  });
  </code></pre>
  
  <p><strong>Datepicker change minimum date code:</strong></p>
  
  <pre><code>var startdate = new Date(2010,4-1,
      4-1,0,0,0);
  
  $("#endtime").datepicker('option','minDate',startdate);
  </code></pre>