Adding form placeholders to text form elements

Question

Is there a way to add placeholders to a form with a module, or should this be done with a form template?

Answer 1

That's an HTML5 placeholder, you can just add it as an attribute to any element and HTML5 enabled browsers will react accordingly:

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'some_form') {
    $form['some_element']['#attributes']['placeholder'] = t('Placeholder text');
  }
}

A short recursive function like this might be handy if you want to automatically add placeholders for every textfield in a form (based on the field's title in this example):

function MYMODULE_auto_placeholders(&$element) {
  if ( isset($element['#type']) && $element['#type'] == 'textfield') {
    // set placeholder
    $element['#attributes']['placeholder'] = $element['#title'];
    // hide label
    $element['#title_display'] = 'invisible';
  }
  foreach (element_children($element) as $key) {
    MYMODULE_auto_placeholders($element[$key]);
  }
}

Then in your form alter function just call

MYMODULE_auto_placeholders($form);

That method will work for pretty much every textfield on a form, with the exception of those that are added in #process functions (like the alt and title textfields of an image field for example).

Answer 2

Just add the placeholder in the #attributes array for the form field element, such as in the following code.

   $form['my_textfield'] = array(
      '#type' => 'textfield',
      '#attributes' => array(
        'placeholder' => t('My placeholder text'),
      ),
    );

Answer 3

I tried Clive's answer:

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'some_form') {
    $form['some_element']['#attributes']['placeholder'] = t('Placeholder text');
  }
}

But to my surprise, I got the placeholder in wrapper of textfield, not textfield itself. Then I tried a variation as follows, it worked!

function MYMODULE_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'some_form') {
    $form['some_element']['und'][0]['value']['#attributes']['placeholder'] = t('Placeholder text');
  }
}

Answer 4

Stumbled upon this and thought Clive's answer seemed nice to automatically add placeholders.

Thou, a few minor changes are needed to get it right in drupal 8, so here's pretty much the same answer, but suitable for your drupal 8 theme.

/**
 * Implements hook_form_alter
 */
function THEME_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
  add_placeholders($form);
}


/**
 * Add placeholders to suitable form elements -> textfield, password, email, textarea
 */
function add_placeholders(&$element) {
  if(isset($element['#type']) && in_array($element['#type'], ['textfield', 'password', 'email', 'textarea'])) {
    $element['#attributes']['placeholder'] = $element['#title'];
  }
  foreach(\Drupal\Core\Render\Element::children($element) as $key) {
    add_placeholders($element[$key]);
  }
}

Answer 5

Simply add the code for placeholder text

/**
 * Implements hook_form_alter
 */

function MODULENAME_form_alter(&$form, \Drupal\Core\Form\FormStateInterface 
 $form_state, $form_id) {
  form['field_YOURFIELDNAME']['widget'][0]['value']['#placeholder'] = t('Some text');
}

Answer 6

I've found this solution here that worked for me:

/**

 * Implements template_preprocess_input().

 */

function MYTHEME_preprocess_input(&$variables) {

  // Set a placeholder for all search form elements.

  if ($variables['attributes']['type'] == 'search') {

    $variables['attributes']['placeholder'] = $variables['element']['#title']; 

  }

}

Answer 7

If you want to target a form instance directly use hook_form_FORM_ID_alter. Might be tidier than using conditionals. My solution for targeting the search form block instance only.

function eyecare_form_search_block_form_alter(&$form, $form_state) {
  $form['keys']['#attributes']['placeholder'] = t('Search');
}