I'm trying to customize text for a file upload widget in Drupal 8.

Here is a screenshot of the widget:

File upload widget

I just want to display the first 15 MB which I added as file field description text in the content type.

The trouble is the last 3 lines of text have no HTML tags so I can't selectively hide it with display:none;. Here is what I mean:

HTML for file upload

I tried this CSS but it doesn't work:

#edit-field-dataset-file-0--description * {

#edit-field-dataset-file-0--description p {
    display:inline !important;

Does anyone have any suggestions?

  • 2
    There's a chance that a form alter might help in this case but I am not sure, I'll see if I have some time to test it out. Dec 28, 2019 at 17:12
  • Yeah, try to hook into the form using hook_form_alter and unset the description.
    – leymannx
    Dec 28, 2019 at 17:24
  • Thanks @DannyEnglander @leymannx! I used hook_field_widget_form_alter. Feel free to post your own code which I can accept as an answer but in the meantime I'm going to post a temporary solution.
    – pmagunia
    Dec 28, 2019 at 17:48

3 Answers 3


I used hook_field_widget_form_alter as suggested by DannyEnglander and leymannx.

8.8.x hook_field_widget_form_alter

Replace MYMODULE with your custom module's name and alter the element array to suit your needs.

 * Implements hook_field_widget_form_alter().
function MYMODULE_field_widget_form_alter(&$element, \Drupal\Core\Form\FormStateInterface $form_state, $context) {
  if (get_class($context['widget']) === 'Drupal\file\Plugin\Field\FieldWidget\FileWidget' && !empty($context['form']['#attributes'])) {
    $element['#description'] = '<p>File must be less than <strong>15 MB</strong>.<br/>Allowed types: <code>txt csv tsv xls xlsx sav sas7bdat</code></p>';
  • Looks like you've got it! I think you can accept this as the answer. Dec 28, 2019 at 19:11
  • 1
    SE says I can accept the answer in two days. I hope I don't forget.
    – pmagunia
    Dec 28, 2019 at 21:28

If altering the file field widget description in hook_field_widget_form_alter() doesn't work.

You can try to add a process function to change the description like it is mentioned by gnuget in this Drupal issue :

 * Implements hook_field_widget_form_alter().
function HOOK_field_widget_form_alter(&$element, FormStateInterface &$form_state, $context) {
  if (isset($element['#field_name']) && $element['#field_name'] == 'field_media_image') {
      // Add process callback to change field description.
      $element['#process'][] = '_change_description';

 *  The description field is build in a #process callback so we need to add another callback.
function _change_description($element, FormStateInterface $form_state, $form) {
  $element['#description'] = t('Your new description');
  return $element;

You can add a preprocess function like this:

function theme_preprocess_file_upload_help(array &$variables) {
  $description = $variables['descriptions']; // It's where the three objects are, you can manipulate the description.

Or if you want just to add some wrappers around each element, modify the template file-upload-help.html.twig. Currently it looks like this:

 * @file
 * Theme override to display help text for file fields.
 * Available variables:
 * - descriptions: Lines of help text for uploading a file.
 * @see template_preprocess_file_upload_help()
{{ descriptions|safe_join('<br />') }}

Instead you can do:

{% for item in descriptions %}
  <div class="help-text-item">
    {{ item }}
{% endfor %}

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