title: Contact Form 7 on_submit is not working
body: <p>I am trying to show an alert when the form is submitted.</p>
  
  <p>I added this code to "Additional Settings" on Contact Form 7 plugin (Version 4.2.2)</p>
  
  <p>on_submit:"alert('Submitted');"</p>
  
  <p>Nothing appears.</p>
  
  <ul>
  <li>No errors nor warnings at console</li>
  <li>No errors nor warnings at firebug</li>
  <li>I guess no Javascript conflict since Contact Form 7    succesfully
  sends emails</li>
  <li>I am sure that form is "submitted" because    i can    see Contact
  Form 7 form validation errors</li>
  </ul>
  
  <p>Any ideas how to solve or debug further this issue?</p>