Form generation

Same name and namespace in other branches
  1. 9 core/core.api.php \form_api
  2. 8.9.x core/core.api.php \form_api
  3. 10 core/core.api.php \form_api
  4. 11.x core/core.api.php \form_api

Functions to enable the processing and display of HTML forms.

Drupal uses these functions to achieve consistency in its form processing and presentation, while simplifying code and reducing the amount of HTML that must be explicitly generated by modules.

The primary function used with forms is drupal_get_form(), which is used for forms presented interactively to a user. Forms can also be built and submitted programmatically without any user input using the drupal_form_submit() function.

drupal_get_form() handles retrieving, processing, and displaying a rendered HTML form for modules automatically.

Here is an example of how to use drupal_get_form() and a form builder function:

$form = drupal_get_form('my_module_example_form');
function my_module_example_form($form, &$form_state) {
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Submit'),
  return $form;
function my_module_example_form_validate($form, &$form_state) {
  // Validation logic.
function my_module_example_form_submit($form, &$form_state) {
  // Submission logic.

Or with any number of additional arguments:

$extra = "extra";
$form = drupal_get_form('my_module_example_form', $extra);
function my_module_example_form($form, &$form_state, $extra) {
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => $extra,
  return $form;

The $form argument to form-related functions is a structured array containing the elements and properties of the form. For information on the array components and format, and more detailed explanations of the Form API workflow, see the Form API reference and the Form API documentation section. In addition, there is a set of Form API tutorials in the Form Example Tutorial which provide basics all the way up through multistep forms.

In the form builder, validation, submission, and other form functions, $form_state is the primary influence on the processing of the form and is passed by reference to most functions, so they use it to communicate with the form system and each other.

See drupal_build_form() for documentation of $form_state keys.


includes/, line 25


Title Sort descending File name Summary
date_validate includes/ Validates the date type to prevent invalid dates (e.g., February 30, 2006).
drupal_build_form includes/ Builds and process a form based on a form id.
drupal_form_submit includes/ Retrieves, populates, and processes a form.
drupal_get_form includes/ Returns a renderable form array for a given form ID.
drupal_prepare_form includes/ Prepares a structured form array.
drupal_process_form includes/ Processes a form submission.
drupal_rebuild_form includes/ Constructs a new $form from the information in $form_state.
drupal_redirect_form includes/ Redirects the user to a URL after a form has been processed.
drupal_retrieve_form includes/ Retrieves the structured array that defines a given form.
drupal_validate_form includes/ Validates user-submitted form data in the $form_state array.
element_validate_integer includes/ Form element validation handler for integer elements.
element_validate_integer_positive includes/ Form element validation handler for integer elements that must be positive.
element_validate_number includes/ Form element validation handler for number elements.
form_builder includes/ Builds and processes all elements in the structured form array.
form_clear_error includes/ Clears all errors against all form elements made by form_set_error().
form_error includes/ Flags an element as having an error.
form_execute_handlers includes/ Executes custom validation and submission handlers for a given form.
form_get_cache includes/ Fetches a form from cache.
form_get_error includes/ Returns the error message filed against the given form element.
form_get_errors includes/ Returns an associative array of all errors if any.
form_get_options includes/ Returns the indexes of a select element's options matching a given key.
form_load_include includes/ Ensures an include file is loaded whenever the form is processed.
form_options_flatten includes/ Allows PHP array processing of multiple select options with the same value.
form_pre_render_conditional_form_element includes/ Adds form element theming to an element if its title or description is set.
form_pre_render_fieldset includes/ Adds members of this group as actual elements for rendering.
form_process_actions includes/ Processes a form actions container element.
form_process_autocomplete includes/ Process function to prepare autocomplete data.
form_process_button includes/ Processes a form button element.
form_process_checkbox includes/ Sets the #checked property of a checkbox element.
form_process_checkboxes includes/ Processes a checkboxes form element.
form_process_container includes/ Processes a container element.
form_process_date includes/ Expands a date element into year, month, and day select elements.
form_process_fieldset includes/ Arranges fieldsets into groups.
form_process_machine_name includes/ Processes a machine-readable name form element.
form_process_password_confirm includes/ Expand a password_confirm field into two text boxes.
form_process_radios includes/ Expands a radios element into individual radio elements.
form_process_select includes/ Processes a select list form element.
form_process_tableselect includes/ Creates checkbox or radio elements to populate a tableselect table.
form_process_vertical_tabs includes/ Creates a group formatted as vertical tabs.
form_process_weight includes/ Expands a weight element into a select element.
form_select_options includes/ Converts an array of options into HTML, for use in select list form elements.
form_set_cache includes/ Stores a form in the cache.
form_set_error includes/ Files an error against a form element.
form_set_value includes/ Changes submitted form values during form validation.
form_state_defaults includes/ Retrieves default values for the $form_state array.
form_state_keys_no_cache includes/ Returns an array of $form_state keys that shouldn't be cached.
form_state_values_clean includes/ Removes internal Form API elements and buttons from submitted form values.
form_type_checkboxes_value includes/ Determines the value for a checkboxes form element.
form_type_checkbox_value includes/ Determines the value for a checkbox form element.
form_type_image_button_value includes/ Determines the value for an image button form element.
form_type_password_confirm_value includes/ Determines the value for a password_confirm form element.
form_type_radios_value includes/ Form value callback: Determines the value for a #type radios form element.
form_type_select_value includes/ Determines the value for a select form element.
form_type_tableselect_value includes/ Determines the value for a tableselect form element.
form_type_textarea_value includes/ Determines the value for a textarea form element.
form_type_textfield_value includes/ Determines the value for a textfield form element.
form_type_token_value includes/ Determines the value for form's token value.
form_validate_machine_name includes/ Form element validation handler for machine_name elements.
map_month includes/ Helper function for usage with drupal_map_assoc to display month names.
password_confirm_validate includes/ Validates a password_confirm element.
theme_button includes/ Returns HTML for a button form element.
theme_checkbox includes/ Returns HTML for a checkbox form element.
theme_checkboxes includes/ Returns HTML for a set of checkbox form elements.
theme_container includes/ Returns HTML to wrap child elements in a container.
theme_date includes/ Returns HTML for a date selection form element.
theme_fieldset includes/ Returns HTML for a fieldset form element and its children.
theme_file includes/ Returns HTML for a file upload form element.
theme_form includes/ Returns HTML for a form.
theme_form_element includes/ Returns HTML for a form element.
theme_form_element_label includes/ Returns HTML for a form element label and required marker.
theme_form_required_marker includes/ Returns HTML for a marker for required form elements.
theme_hidden includes/ Returns HTML for a hidden form element.
theme_image_button includes/ Returns HTML for an image button form element.
theme_password includes/ Returns HTML for a password form element.
theme_radio includes/ Returns HTML for a radio button form element.
theme_radios includes/ Returns HTML for a set of radio button form elements.
theme_select includes/ Returns HTML for a select form element.
theme_submit includes/ Returns HTML for a submit button form element.
theme_tableselect includes/ Returns HTML for a table with radio buttons or checkboxes.
theme_textarea includes/ Returns HTML for a textarea form element.
theme_textfield includes/ Returns HTML for a textfield form element.
theme_vertical_tabs includes/ Returns HTML for an element's children fieldsets as vertical tabs.
weight_value includes/ Sets the value for a weight element, with zero as a default.
_drupal_invalid_token_set_form_error includes/ Helper function to call form_set_error() if there is a token error.
_form_builder_handle_input_element includes/ Adds the #name and #value properties of an input element before rendering.
_form_button_was_clicked includes/ Determines if a given button triggered the form submission.
_form_element_triggered_scripted_submission includes/ Detects if an element triggered the form submission via Ajax.
_form_options_flatten includes/ Iterates over an array and returns a flat array with duplicate keys removed.
_form_set_class includes/ Sets a form element's class attribute.
_form_validate includes/ Performs validation on form elements.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.