title: Javascript element.addEventListener is not a function
body: <p>i'm tryin' to make a pop-up navbar for tablet and mobile modes but i've got stuck on the javascript</p>
  <pre><code>&lt;script&gt;
  const navbar = document.getElementById('navbar')
  const popup = document.getElementsByClassName(&quot;menu-btn&quot;)
  
  popup.addEventListener(&quot;click&quot;, show ());
  
  function show() {
      navbar.classList.toggle('duh');
  }
  
  &lt;/script&gt;
  </code></pre>