title: Showing a loader while input file uploading
body: <p>I have an HTML form with input file like this:</p>
  
  <pre><code>&lt;form method="POST" enctype="multipart/form-data"&gt;
      &lt;input type="file" name="pic" accept="image/*"&gt;
      &lt;button type="submit"&gt;Salva&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>Sometimes, specially with large files, upload process goes on for a long time and user doesn't know what is happening.</p>
  
  <p>Is there any jQuery/javascript event that can do stuff when uploading starts and do others when it finishes?</p>