title: Document.getElementByClassName not working
body: <p>I'm trying to use Document.getElementByClassName, but it isn't working. I've included my code below. I'd appreciate any help.</p>
  
  <p>HTML document:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;!doctype html&gt;
  &lt;html&gt;
  
  &lt;head&gt;
    &lt;meta charset=utf-8&gt;
    &lt;title&gt;Day Practice&lt;/title&gt;
    &lt;style&gt;&lt;/style&gt;
  &lt;/head&gt;
  
  &lt;body&gt;
    &lt;h1 class=myclass&gt; Some text&lt;/h1&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>JavaScript code:</p>
  
  <pre class="lang-js prettyprint-override"><code>var change = document.getElementByClassName("myclass");
  change.innerHTML = "New text";
  </code></pre>