title: How to add "close" button on a pop up?
body: <p>I open a pop up and i want to add a "close" button on it. The "close" button will close the pop up when clicked.
  Here is the code with open the popup:</p>
  
  <p><strong>JavaScript</strong></p>
  
  <pre><code>$(document).ready(function(){
      $('#contener&gt;li&gt;a[rel=external]').click(function(){
      var mywindow= window.open(url,'','menubar=no, status=no, scrollbars=yes, menubar=no, width=1200, height=300');
  
      mywindow.focus();
  
      return false;   
  
      }); 
    });
  </code></pre>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;ul id="contener"&gt;
       &lt;li&gt;&lt;a href="/app/contact/user" rel="external"&gt;User&lt;/a&gt;&lt;/li&gt;
       &lt;li&gt;&lt;a href="/app/contact/notuser"&gt;Not User&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>Thanks</p>