index.html

<!DOCTYPE html>
<html>

<head>
  <title>Simple Socket Example</title>
  <script type="module">
    // Import the functions you need from the SDKs you need
    import { initializeApp } from "https://www.gstatic.com/firebasejs/10.12.2/firebase-app.js";
    import { getDatabase, ref, set } from "https://www.gstatic.com/firebasejs/10.12.2/firebase-database.js";
    import { getAnalytics } from "https://www.gstatic.com/firebasejs/10.12.2/firebase-analytics.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: "AIzaSyD7pM_SPRCiWNtrD4lZrpGmt6WWtG0c77Q",
      databaseURL: "https://pgc-db-default-rtdb.firebaseio.com/",
      authDomain: "pgc-db.firebaseapp.com",
      projectId: "pgc-db",
      storageBucket: "pgc-db.appspot.com",
      messagingSenderId: "297418588201",
      appId: "1:297418588201:web:1fb0bbd85902024ac49c38",
      measurementId: "G-JDPZHN0EK5"
    };

    // Initialize Firebase
    const app = initializeApp(firebaseConfig);
    let db = getDatabase(app);

    let save_user = (alias, phone) => {
      set(ref(db, 'users/' + alias), {
        alias: alias,
        phone: phone
      });
    }

    save_user("CSC dudh", "123-456-7890")
  </script>
</head>

<body>
  <div>
    <h1> Hello World </h1>
  </div>
  <div>
    <p id="data"></p>
  </div>
</body>

</html>