Backend\Modules\FormBuilder\Ajax\Sequence::execute PHP Method

    public function execute()
    {
        parent::execute();
        // get parameters
        $formId = \SpoonFilter::getPostValue('form_id', null, '', 'int');
        $newIdSequence = trim(\SpoonFilter::getPostValue('new_id_sequence', null, '', 'string'));
        // invalid form id
        if (!BackendFormBuilderModel::exists($formId)) {
            $this->output(self::BAD_REQUEST, null, 'form does not exist');
        } else {
            // list id
            $ids = (array) explode('|', rtrim($newIdSequence, '|'));
            // loop id's and set new sequence
            foreach ($ids as $i => $id) {
                $id = (int) $id;
                // get field
                $field = BackendFormBuilderModel::getField($id);
                // from this form and not a submit button
                if (!empty($field) && $field['form_id'] == $formId && $field['type'] != 'submit') {
                    BackendFormBuilderModel::updateField($id, array('sequence' => $i + 1));
                }
            }
            $this->output(self::OK, null, 'sequence updated');
        }
    }