signup.html

<html>
    <head>
        <title>Firebase_form</title>
        <link rel="stylesheet" href="css/style.css">
    </head>
    <body>
        <div class="box">
            <div class="form">
                <h2>SAHAH</h2>
                <form>
                    <div class="inputbox">
                        <input type="text" value="" id="username" required>
                        <span>Username</span>
                    </div>
                    <div class="inputbox">
                        <input type="email" value="" id="email" required>
                        <span>E-mail</span>
                    </div>
                    <div class="inputbox">
                        <input type="text" value="" id="phone" required>
                        <span>Phone Number</span>
                    </div>
                    
                    <input type="submit" value="Register" class="sub" id="submit">
                </form>
            </div>
        </div>
        <script type="module">
              // Import the functions you need from the SDKs you need
  import { initializeApp } from "https://www.gstatic.com/firebasejs/10.1.0/firebase-app.js";
  import { getDatabase,ref,set,get,child } from "https://www.gstatic.com/firebasejs/10.1.0/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
  const firebaseConfig = {
    apiKey: "AIzaSyA4OOfPmoM0_qpKG7zaNhMmRGg-NNrLZjc",
    authDomain: "sahah-b52ec.firebaseapp.com",
    databaseURL: "https://sahah-b52ec-default-rtdb.firebaseio.com/",
    projectId: "sahah-b52ec",
    storageBucket: "sahah-b52ec.appspot.com",
    messagingSenderId: "213546548711",
    appId: "1:213546548711:web:9b5661349cc635fe6c1142"
  };
  
  // Initialize Firebase
  const app = initializeApp(firebaseConfig);
  const db = getDatabase (app);
  document.getElementById("submit").addEventListener("click", function(e) {

    e.preventDefault();
    set (ref(db, 'user/' + document.getElementById("username").value),
  {

    username: document.getElementById("username").value,
    email: document.getElementById("email").value,
    PhoneNumber: document.getElementById("phone").value
    });
    alert("Register Successful!");
    window.location.href = "index.html";
     
    })
    
        </script>
    </body>
</html>