title: Class extend by jQuery UI
body: <p>I need do change some method in jQuery UI datepicker but I dont wanna modify original code, so how my class can extends jquery ui and override some method?</p>
  
  <pre><code>function MyDatepicker() {
  this.extend(jQuery); // extend jquery??
  
      this.datepicker.onclick = function () {
          alert("test");
      }
  }
  </code></pre>