I have created a webform hook (using hook_form_alter) which searches for a particularly named input and appends an ID for JS code to make changes on the front end.

It works fine however I have come across an issue where if that input is made part of a fieldset, it can no longer find it. This is to do with how the $form array is rearranged to include children inputs in the fieldset array.

My question is: how do I find an element by name regardless of whether it is part of a fieldset or not?

This is the code I'm using, which works fine for parent level inputs but not when it is part of a fieldset. How do I get this to work where I don't need to know what the fieldset is called (because I won't always know).

function MODULE_form_alter(&$form, &$form_state, $form_id){
  $form['submitted']["certain_name"]['#default_value'] = '';
  $form['submitted']["certain_name"]['#attributes']['id'] = 'new-id';
  $form['submitted']["certain_name"]['#ajax'] = array(
    'event'    => 'change',
    'callback' => 'module_js_lookup(this.value)'

1 Answer 1


Unfortunately, to access/modify and form fields in Webform using the form API and hooks, you have to know/include the fieldset hierarchies in the array calls as you observed.

For example:




Rather than set a callback function on the form element in your hook_form_alter, you may just need to find the element type with particular machine name using vanilla javascript or jQuery in either:

  • your theme's assorted javascript files as Drupal behavior
  • the custom module as a separate script

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