title: Why my drop down menu suddenly disappear after click for the first time?
body: <p>You can see my live demo <a href="http://d3sine.com/demo/nana/index_mobile.html" rel="nofollow">here.</a> I want the drop down menu to display properly. Now it's suddenly hidden when first clicked. And I want to make drop down menu to be disappear when click anywhere outside drop down menu that is/are currently shown. How am I supposed to do that?</p>
  
  <p>This is my jQuery code</p>
  
  <pre><code>$(document).ready(function () { 
      $('#jsddm &gt; li').click(function(e){
          e.preventDefault();
          $(this).find('ul').eq(0).css('visibility', 'visible').slideToggle();
      });
  });
  </code></pre>
  
  <p>I noticed that if <code>.css('visibility', 'visible')</code> is removed, the drop down menu will not       work anymore.</p>