title: Sending nested FormData on AJAX
body: <p>I need to send some data using ajax and FormData, because I want to send a file and some other parameters. The way I usually send data is this:</p>
  
  <pre><code>$.ajax({
      type:       'POST',
      url:        'some_url',
      dataType:   'json',
      processData:false,
      contentType:false,
      data:{
          Lvl_1-1: 'something',
          Lvl_1-2: 'something',
          Lvl_1-3: {
              Lvl_1-3-1: "something",
              Lvl_1-3-2: "something",
              Lvl_1-3-3: "something",
          },
      },
      ...
  });
  </code></pre>
  
  <p>If I don't use FormData(), I have no problem, but when using FormData(), only the data on Lvl1 is ok, but anything nested is displayed as string like this</p>
  
  <pre><code>&lt;b&gt;array&lt;/b&gt; &lt;i&gt;(size=3)&lt;/i&gt;
      'Lvl1-1' &lt;font color='#888a85'&gt;=&amp;gt;&lt;/font&gt; &lt;small&gt;string&lt;/small&gt; 
          &lt;font color='#cc0000'&gt;'Something'&lt;/font&gt; 
          &lt;i&gt;(length=23)&lt;/i&gt;
      'Lvl1-2' &lt;font color='#888a85'&gt;=&amp;gt;&lt;/font&gt; &lt;small&gt;string&lt;/small&gt; 
          &lt;font color='#cc0000'&gt;''Something''&lt;/font&gt; &lt;i&gt;(length=3)&lt;/i&gt;
      'Lvl1-3' &lt;font color='#888a85'&gt;=&amp;gt;&lt;/font&gt; &lt;small&gt;string&lt;/small&gt; 
          &lt;font color='#cc0000'&gt;'[object Object]'&lt;/font&gt; &lt;i&gt;(length=17)&lt;/i&gt;
  </code></pre>
  
  <p>If I use FormData() to encode the data inside Lvl1-3, instead of <code>[object Object]</code> I get <code>[object FormData]</code></p>
  
  <p>How do I get an array instead of string on Lvl1-3?</p>
  
  <p>NOTE: If the file is on top level (Lvl_1) I can send the file with no problems using FormData(). I didn't wrote the code of the file attached because that's not the problem, nested data is. I just mentioned the file because that's why I'm using FormData().</p>