title: Magento newsletter ajax request returns null
body: <p>I am trying to send a newsletter subscription request to Magento, but It returns null and nothing happens.</p>
  
  <p>I've searched around and found very different URLs to post the request. And also grabbed the code from the file from base template.</p>
  
  <p>In fact, maybe I am not sending the correct parameters or whatever.</p>
  
  <p><strong>This is the code in use:</strong></p>
  
  <pre><code>&lt;form method="post" id="newsletter-form"&gt;
  &lt;input type="hidden" class="url" value="&lt;?php echo $this-&gt;getUrl('newsletter/subscriber/new') ?&gt;"&gt;
      &lt;input id="newsletter" type="text" name="email" placeholder="RECEBA NOVIDADES" value="" class="input-text myFormInput" maxlength="128" autocomplete="off" style="width: 188px !important"&gt;
      &lt;button type="submit" id="ajax-newsletter-submit" title="CADASTRAR" 
      class="button myFormButton" style="margin-top:20px;margin-left: -107px !important;width: 103px"&gt;CADASTRAR&lt;/button&gt;
  
      &lt;/div&gt;
  &lt;/form&gt; 
  </code></pre>
  
  <p><strong>Javascript</strong>:</p>
  
  <pre><code>   var newsletterSubscriberFormDetail = new VarienForm('newsletter-form');
  
     $j(function() {
         $j("#ajax-newsletter-submit").click(function() {        
          var email =$j("#newsletter").val();
          var url=$j(".url").val();
          var dataString = 'email='+ email;
              if(email=='') {
                 $j("#newsletter").focus();
              } else {
                  var a = email;
                  var filter = /^[a-zA-Z0-9_.-]+@[a-zA-Z0-9]+[a-zA-Z0-9.-]+[a-zA-Z0-9]+.[a-z]{1,4}$/;
                  if(filter.test(a)){
                      $j.ajax({
                          type: "POST",
                          url: url,
                          data: dataString,
                          success: function(){                
                              alert('Assinatura realizada com sucesso!');
                              $j("#newsletter").val('');
                          }
                      });
                  } else {
                      $j("#newsletter").focus();
                  }
              }  
              return false;
          });
      });
  </code></pre>