title: Make button disabled if input type file is empty in bootstrap
body: <p>I have form where the user can upload a file but I want the upload button to be disabled if the input type file does not contain a file how do I do that ?</p>
  
  <pre><code>&lt;form action="/upload" method="post" enctype="multipart/form-data"&gt;
      &lt;div class="form-inline"&gt;
          &lt;div class="form-group"&gt;
              &lt;input type="file" name="fileUploaded"&gt;
          &lt;/div&gt;
          &lt;button type="submit" class="btn btn-sm btn-primary"&gt;Upload file&lt;/button&gt;
      &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>