I am currently working on a Webform that is used to enter some rather complex finance information (think tables with sums and other weird checks).

Since the styling has to be rather specific for this form I decided to create a custom Module that provides a new Webform-Component using the Webform Module Hooks.

That means that I created the HTML and WebForm Structure of the form using the _webform_render_component hook by providing a custom #process function that expands the initial component array to include a bunch of textfields and some custom themes.

function _webform_render_ff_promotion($component, $value = NULL, $filter = TRUE) {
  $element = array(
    '#weight' => $component['weight'],
    '#pre_render' => array('webform_ff_promotion_form_prerender'),
    '#webform_component' => $component,
    '#theme' => 'webform_display_ff_promotion_form',
    '#process' => array('webform_process_ff_promotion_form_expand'),
    '#prefix' => '<div>',
    '#suffix' => '</div>',
  return $element;

And the custom process expansion:

function webform_process_ff_promotion_form_expand($element) {
  $element['general_group'] = array(
    '#type' => 'fieldset',
    '#theme' => 'ff_general_group_fieldset'
  $element['general_group']['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#required' => true

So far that works well and I have the form set up to look and behave as I need it to (saving etc works). Only problem now is validation - I cannot specify any other validations rather than required through the form_api.

I am trying to do this with the Webform Validation Module following this guide. This works and I could now write a really huge list of if (is_numeric(...)) checks to see if the user did only enter numeric values to my textfields - but it feels kind of pointless.

So the main question here being - is there a best practice for custom components that rely on standard components internally (The whole custom component consists of just a bunch of '#type' => 'textfield' elements) to validate without writing a completely custom validator for it?

The Webform Validation Module feels like the wrong tool as it allows the validations to be done by the user in the admin. I'd rather just add more attributes like the '#required' in the FormAPI and have them be checked.

Any help would be greatly appreciated - thanks!

Version Info:

  • Drupal 7.34
  • Webform: 7.x-4.6
  • Webform-Validation: 7.x-1.9

2 Answers 2


It looks like the hook _webform_action_set_component might be used for validation: "Setting the form element allows form validation functions to see the value that webform has set for the given component."



If you just need to make sure the values are numeric, try Elements module. It adds advanced form elements like HTML5 number. Then you can use '#type' => 'numberfield' instead of '#type' => 'textfield'.

Another option is to add a standard validator that suits your needs. For example, you can use '#element_validate' => array('element_validate_number') to validate your numeric fields.

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