title: Javascript to add class when checkbox is selected
body: <p>I have this piece of code:</p>
  
  <pre><code>&lt;div class="quote-box-col14"&gt;
  &lt;label for="seo" class="quote-service-seo"&gt;SEO&lt;/label&gt;
  &lt;input type="checkbox" name="seo" id="seo" value="Y" class="checkbox-seo" /&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>Someone can help with a JavaScript that adds class "selected" to  when checkbox is selected?</p>
  
  <p>Thanks</p>