Preview action

controller.php

<?php

class QuestionController extends BaseController
{
    
    /**
     * @param Request $request
     * @return JsonResponse
     */
    public function saveSessionAction(Request $request)
    {
        $question = new Question();

        $form = $this->createForm(new QuestionType(), $question);
        $form->submit($request);

        $result = false;
        if ($form->isValid()) {
            $questionArray = $question->toArray();

            $this->getSession()->set('question', $questionArray);

            $result = true;
        }

        return new JsonResponse($result);
    }

    /**
     * @Template()
     *
     * @return array
     */
    public function previewAction()
    {
        return [
            'question' => $this->getSession()->get('question'),
        ];
    }
}

xxx.js

$(function () {
    var other_window = false;
    $('button.preview').click(function () {
        $.ajax({
            url: 'path/to/question_save_session',
            data: $('form.question-form').serialize(),
            dataType: 'json',
            type: 'POST',
            success: function (data) {
                if (data) {
                    if (other_window) {
                        other_window.location.reload(true);
                    } else {
                        other_window = window.open('/path/to/question_preview');
                    }
                }
            }
        });

        return false;
    });
});