[campaignmonitor.js] Campaign monitor ajax

campaignmonitor.html

<form class="form-newsletter" action="http://xxxx.createsend.com/t/d/s/xxxx/" method="post" >
  <h3>Newsletter</h3>
  <div class="success">
      Thankyou for signing up!
  </div>
  <div class="error">
      Please check your email address is correct. 
  </div>
  <input name="cm-xxxx-xxxx" type="email" placeholder="Email Address" required />
  <button type="submit" value="Sign Up" name="submit">Sign Up</button>
</form>

campaignmonitor.js

//Handler for Campaignmonitor form
handlerNewsletterSubmit: function() {
  var $form   = $('footer .newsletter form');
  var $success = $form.find('.success');
  var $error   = $form.find('.error');

  $form.submit(function(e) {
    e.preventDefault();

    $error.hide();
    $.getJSON(this.action + "?callback=?",
      $(this).serialize(),
      function(data) {
        if (data.Status === 400) {
          $error.text(data.Message).show();
        } else { // 200
          $form.find('input').val('');
          $success.show();
          js.utilRemoveLightbox();
        }
      }
    ); // end getJson

  }); // end submit
},