<form class="form-horizontal" action="/upload" method="post" enctype="multipart/form-data">
  <div class="control-group">
    <label class="control-label">File upload</label>
    <div class="controls">
      <input type="file" name="file" class="btn-large">
    </div>
  </div>
  <div class="control-group">
    <div class="controls">
      <button type="submit" class="btn btn-large btn-primary">Submit</button>
    </div>
  </div>
</form>