title: Get JSON response from Form Submit
body: <p>I am not front end developer and I'm spending a quite time trying to do so. Hope you guys can help me.
  I have a form which sends files to an API in server, like below:</p>
  
  <pre><code>&lt;form id="uploadForm" action="url/upload/" method="post" enctype="multipart/form-data" accept-charset="ISO-8859-1"&gt;   
  
        &lt;div class="inputFileCustom"&gt;
          &lt;input type="file" size="45" name="file" id="uploadFiles" accept="application/pdf"/&gt;
          &lt;label for="uploadFiles"&gt;
              &lt;div class="ic-bt ic-bt-details ic-bt-text btn btn-border"&gt;
              Choose a file
              &lt;/div&gt;
          &lt;/label&gt;
      &lt;/div&gt;
  
      &lt;input type="submit" value="Upload PDF" class="btn btn-primary" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p><code>url/upload</code> returns a JSON, like:</p>
  
  <pre><code>{ "status": "ok"/"fail" }
  </code></pre>
  
  <p>I need two things:</p>
  
  <ol>
  <li>Prevent submit to redirect to <code>url/upload</code>;</li>
  <li>Get JSON response from server and, if successful, call <code>loadFiles()</code> function (which is already working).</li>
  </ol>
  
  <p>I'm using javascript for <code>loadFiles()</code> function, but its very simple.</p>