Sue mistakenly sent her message twice. Let's use our knowledge of removing elements to remove the duplicate message.

<html>
  <body>
    <h3>WebChat</h3>
    <ul id="messages">
      <li>Ron: You won't believe what happened</li>
      <li>Sue: What 🤩?</li>
      <li id="double">Sue: What 🤩?</li>
    </ul>
    <script>
      var parent = document.getElementById("messages");
      var child = document.getElementById("double");
      //parent.removeChild(child);
    </script>
  </body>
</html>]]>