在Twig文件中显示Bootstrap Alert消息'onsubmit‘

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css">
<script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>

{% if show_alert %}
    <div class="alert alert-success" role="alert">
        提交成功！
    </div>
{% endif %}

<form action="/submit" method="post" onsubmit="showAlert()">
    <!-- 表单内容 -->
    <button type="submit" class="btn btn-primary">提交</button>
</form>

<script>
    function showAlert() {
        // 在提交表单时，设置show_alert变量为true，以显示Alert消息
        document.getElementById('show_alert').value = true;
    }
</script>

// 在后端处理表单提交的逻辑中，将show_alert变量传递给Twig模板
return $this->render('template.twig', ['show_alert' => $_POST['show_alert']]);