title: Issue of jquery.ui.datepicker
body: <p>When using jquery.ui.datepicker,I got a empty div in my page.And it is not hidden. you can see what it looks like:</p>
  
  <p><img src="https://i.stack.imgur.com/tf7mU.png" alt="enter image description here"></p>
  
  <p>I use firebug inspect the code:</p>
  
  <pre><code>&lt;div class="ui-datepicker ui-widget ui-widget-content ui-helper-clearfix ui-corner-all" id="ui-datepicker-div"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>And I checked the css by firebug,it shold be hidden,the css is:</p>
  
  <pre><code>.ui-datepicker {
      display: none;
      padding-bottom: 0;
      padding-left: 0.2em;
      padding-right: 0.2em;
      padding-top: 0.2em;
      width: 17em;
  }
  </code></pre>
  
  <p>but this line:
  <strong>display:none</strong> 
  is strike-through. why this happen? How can I fix this?</p>
  
  <p>Thanks.</p>