title: Javascript detect if child of parent element has a class set
body: <p>This is my code:</p>
  
  <pre><code>&lt;div id="main"&gt;
      &lt;div class="myclass"&gt;&lt;/div&gt;   
  &lt;/div&gt;
  </code></pre>
  
  <p>How can I detect if inside of <code>main</code>div there is an element with <code>myclass</code> set?</p>
  
  <p>PS. Vanilla JS, no jQuery</p>