title: Get the value of checked checkbox?
body: <p>So I've got code that looks like this:</p>
  
  <pre><code>&lt;input class="messageCheckbox" type="checkbox" value="3" name="mailId[]"&gt;
  &lt;input class="messageCheckbox" type="checkbox" value="1" name="mailId[]"&gt;
  </code></pre>
  
  <p>I just need Javascript to get the value of whatever checkbox is currently checked.</p>
  
  <p><strong>EDIT</strong>: To add, there will only be ONE checked box.</p>