Solution 1 :

auth.onAuthStateChanged(function(user){
  if(user){
    // is signed in
    window.location.href = 'https://www.......';
  } else {
    // not signed in
    alert("you are not logged in");
  }
});

How TO – Redirect to Another Webpage

Problem :

I have a problem in identifying the used code that redirect the user to other page, as I copied the code from the internet, but I suffer trying to redirect the user after login; and I need to making sure the user is logged in not because he have the link so he can see the page I want to point out I am using firebase.google.com as a way to check the user
here is my app.js file

firebase.auth().onAuthStateChanged(function(user) {
    if (user) {
      // User is signed in.
  
      document.getElementById("user_div").style.display = "block";
      document.getElementById("login_div").style.display = "none";
  
      var user = firebase.auth().currentUser;
  
      if(user != null){
  
        var email_id = user.email;
        document.getElementById("user_para").innerHTML = "Welcome:" + email_id;
  
      }
  
    } else {
      // No user is signed in.
  
      document.getElementById("user_div").style.display = "none";
      document.getElementById("login_div").style.display = "block";
  
    }
  });
  
  function login(){
  
    var userEmail = document.getElementById("email_field").value;
    var userPass = document.getElementById("password_field").value;
  
    firebase.auth().signInWithEmailAndPassword(userEmail, userPass).catch(function(error) {
      // Handle Errors here.
      var errorCode = error.code;
      var errorMessage = error.message;
  
      window.alert("Error : " + errorMessage);
  
      // ...
    });
  
  }
  
  function logout(){
    firebase.auth().signOut();
  }

  auth.onAuthStateChanged(function(user){
    if(user){
      //is signed in
    }else{
        alert("you are not logged in");
      //not signed in
    }
  });
*{
  direction: rtl;
}
body {
    background: #fff;
    padding: 0px;
    margin: 0px;
    font-family: 'Nunito', sans-serif;
    font-size: 16px;
  }
  
  input, button {
    font-family: 'Nunito', sans-serif;
    font-weight: 700;
  }
  .logo{
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 128px;
    height: 128px;
  }
  .main-div, .loggedin-div {
    width: 20%;
    margin: 0px auto;
    margin-top: 150px;
    padding: 20px;
    display: none;
  }
  .main-div input {
    display: block;
    border: 1px solid #ccc;
    border-radius: 5px;
    background: #fff;
    padding: 15px;
    outline: none;
    width: 100%;
    margin-bottom: 20px;
    transition: 0.3s;
    -webkit-transition: 0.3s;
    -moz-transition: 0.3s;
  }
  
  .main-div input:focus {
    border: 1px solid #777;
  }
  
  .main-div button, .loggedin-div button {
    background: #5d8ffc;
    color: #fff;
    border: 1px solid #5d8ffc;
    border-radius: 5px;
    padding: 15px;
    display: block;
    width: 100%;
    transition: 0.3s;
    -webkit-transition: 0.3s;
    -moz-transition: 0.3s;
  }
  
  .main-div button:hover, .loggedin-div button:hover {
    background: #fff;
    color: #5d8ffc;
    border: 1px solid #5d8ffc;
    cursor: pointer;
  }
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
    <link rel="shortcut icon" href="imagesfavicon.ico" type="image/x-icon">
    <link href="https://fonts.googleapis.com/css?family=Nunito:400,600,700" rel="stylesheet">
</head>
<body>

  <div id="login_div" class="main-div">
      <img src="./images/logo.png" alt="logo" class="logo">
    <input type="email" placeholder="email" id="email_field" />
    <input type="password" placeholder="password" id="password_field" />

    <button onclick="login()">login</button>
  </div>

<div id="user_div" class="loggedin-div">
    <h3>welcome</h3>
    <p id="user_para">Welcome to Firebase web login Example. You're currently logged in.</p>
    <button onclick="logout()">logout</button>
  </div>



  <script src="https://www.gstatic.com/firebasejs/4.8.1/firebase.js"></script>

  <script>
    // Your web app's Firebase configuration
    var firebaseConfig = {
      apiKey: "******************************",
      authDomain: "******************************",
      databaseURL: "******************************",
      projectId: "******************************",
      storageBucket: "******************************",
      messagingSenderId: "******************************",
      appId: "******************************"
    };
    // Initialize Firebase
    firebase.initializeApp(firebaseConfig);
  </script>
  <script src="app.js"></script>

</body>
</html>

I want your help, please 🙂

Comments

Comment posted by Nick390

I am surprised The community is very big and nobody stopped to help me :(.

Comment posted by Nick390

Thank you for your response, after a long wait I decided to use other methods outside Firebase 🙂

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