title: Getting extra 'li' in ul
body: <p>Every time user click on li, new ul should be added to that li, basically want to create binary tree using ul</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$('#tree').on('click','li', function(){
  
    $(this).append('&lt;ul style="display:block;"&gt;&lt;li&gt;list1&lt;/li&gt;&lt;li&gt;list2&lt;/li&gt;&lt;/ul&gt;'); });</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"&gt;&lt;/script&gt;
  &lt;ul id="tree"&gt;
       &lt;li&gt;
      sdfsdf 
     &lt;/li&gt;
    &lt;/ul&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>list is getting added twice when list1 is clicked</p>