转换后的占位符值不能提取到Symfony 4表单域

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;

class MyFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add('myField', TextType::class, [
                'placeholder' => 'Enter your text here',
            ]);
    }
}

{{ form_start(form) }}
    {{ form_row(form.myField) }}
{{ form_end(form) }}

use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

public function myAction(Request $request)
{
    $form = $this->createForm(MyFormType::class);
    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {
        $data = $form->getData();
        // 处理数据
    }

    return $this->render('my_template.html.twig', [
        'form' => $form->createView(),
    ]);
}

document.addEventListener('DOMContentLoaded', function () {
    // 确保没有JavaScript代码干扰表单域
});