title: Javascript add class
body: <p>I have this line in javascript <code>document.getElementById("load").classList.add("active");</code> but not working. Where is problem and what I must change?</p>
  
  <p>In html I have </p>
  
  <pre><code>&lt;div class="loading" id="load"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>And I need with javascript add class <code>active</code> to this div.</p>