'textfield', '#title' => t('Characters to use in the code'), '#default_value' => variable_get('css_captcha_allowed_characters', CSS_CAPTCHA_DEFAULT_ALLOWED_CHARACTERS), ); $form['css_captcha_code_length'] = array( '#type' => 'select', '#title' => t('Code length'), '#options' => drupal_map_assoc(array(4, 5, 6, 7, 8, 9, 10)), '#default_value' => variable_get('css_captcha_code_length', 6), ); $form['#validate'][] = 'css_captcha_settings_form_validate'; return system_settings_form($form); } /** * Validation function */ function css_captcha_settings_form_validate($form, &$form_state) { if (preg_match('/\s/', $form_state['values']['css_captcha_allowed_characters'])) { form_set_error('css_captcha_allowed_characters', t('The list of characters to use should not contain spaces.')); } }