title: Symfony 3.4 - jQuery AJAX request no result found in controller
body: <p>Currently, I work on a project and I try to get data from an AJAX request which is the method is "POST".</p>
  
  <p>This is my JS code :</p>
  
  <pre><code>function ajax() {
      var form = new FormData();
      // Data from contenteditable which is id is "title".
      form.append('article[title]', $('#title').html().trim());
      // Data from contenteditable which is id is "content".
      form.append('article[content]', $('#content').html().trim());
      // Data from input checkbox which is id is "article_parution".
      form.append('article[parution]', $('#article_parution').val());
      // Data from input hiden which is id is "article__token".
      form.append('article[_token]', $('#article__token').val());
  
      $.ajax({
          method: "POST",
          url: '{{ path("add_article") }}', // /admin/add
          processData: false,
          cache: false,
          data: form
      })
  }
  </code></pre>
  
  <p>I have used "console.log()" to verify is the data exists and it's the case.</p>
  
  <p>The problem is when I try to use this in my controller :</p>
  
  <pre><code>$title = $request-&gt;request-&gt;get('article[title]');
  </code></pre>
  
  <p>$title is null, why ? </p>
  
  <p>Moreover, this URL (/admin/add) is in a protected area by <em>FosUserBundle</em> in the website (the user must be connected in admin to access in this website part).</p>