问JS防火墙数据库错误db.ref不是一个函数

EN

 <script type="module">
    // Import the functions you need from the SDKs you need
    import { initializeApp } from "https://www.gstatic.com/firebasejs/9.8.3/firebase-app.js";
    import { getAnalytics } from "https://www.gstatic.com/firebasejs/9.8.3/firebase-analytics.js";
    import { getDatabase } from "https://www.gstatic.com/firebasejs/9.8.3/firebase-database.js";;

    // TODO: Add SDKs for Firebase products that you want to use
    // https://firebase.google.com/docs/web/setup#available-libraries

    // Your web app's Firebase configuration
    // For Firebase JS SDK v7.20.0 and later, measurementId is optional
    const firebaseConfig = {
      apiKey: "xxxxxxxxxxxxxxxxxxxxx",
      authDomain: "xx.x.xxx",
      databaseURL: "xxxxxxxxxxxxxxxx",
      projectId: "xxxxx",
      storageBucket: "xxxxxxxxx",
      messagingSenderId: "xxxx",
      appId: "xxxxx",
      measurementId: "xxxxxxx"
    };

    const fireapp = initializeApp(firebaseConfig);
    const db = getDatabase(fireapp);
    const ref = db.ref('server/saving-data/fireblog');
  </script>