this is my realtime database

I use firebase realtime database, I use rules as below:

 {
  "rules": {
    "$uid": {
    ".read":"$uid === auth.uid",
    ".write": false
  }
}
}

when I use the playground rules as below it works, here I managed to read the 121212 data above.

This is my code snippet.

<script>
// Import the functions you need from the SDKs you need
    import {
        initializeApp
    } from "https://www.gstatic.com/firebasejs/9.6.11/firebase-app.js";
    import {
        getDatabase,
        ref,
        onValue,
    } from "https://www.gstatic.com/firebasejs/9.6.11/firebase-database.js";
    import {
        getAuth,
        signInWithCustomToken,
        createCustomToken
    } from "https://www.gstatic.com/firebasejs/9.6.11/firebase-auth.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: "",
        authDomain: "",
        databaseURL: "",
        projectId: "",
        storageBucket: "",
        messagingSenderId: "",
        appId: "",
        measurementId: ""
    };

    // Initialize Firebase
    const app = initializeApp(firebaseConfig);

</script>

The problem is, I want to read 121212 data via javascript.