title: What does the "Uncaught TypeError: Cannot read property" JS error mean?
body: <p>Can someone explain to me what these errors mean?</p>
  
  <p>I need the answers for a school project.</p>
  
  <pre><code>Error 1 "Uncaught TypeError: Cannot read property 'getBoundingClientRect' of null"
  Error 2 "Uncaught TypeError: Cannot read property 'dom' of null"
  </code></pre>