title: Open a pop-up on clicking anchor instead of new window
body: <p>I want to create a link to a pop-up. My problem is, when I click the button for the first time, it will render a pop-up but, when I click it further, it will open new windows. </p>
  
  <p>I want to make sure that, only one pop-up gets rendered and, prevent opening of new windows when clicked multiple times.</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;a class="nav-link" href="visitor.html" target="popup" onclick="window.open('visitor.html','name','width=600,height=600')"&gt;Some Text&lt;/a&gt;
  </code></pre>