Key Points for the Visual Image:

• Frontend (JavaScript): Handles input forms (email/password).
• Firebase Authentication: Provides secure login/signup, password reset, and user management.
• Database (Firebase Firestore/Realtime DB): Stores user data if needed.
• Steps:
  1. Create a Firebase project.
  2. Add Firebase SDK to your project.
  3. Build signup & login forms with JavaScript.
  4. Use Firebase Auth methods (createUserWithEmailAndPassword, signInWithEmailAndPassword).
  5. Add authentication state persistence.
  6. Deploy & secure your app

🌐 Building a Login System with JavaScript & Firebase

🔹 Why Firebase?

• Pre-built authentication system.
• Supports Email/Password, Google, Facebook, GitHub logins.
• Scalable and secure.

🛠️ Step-by-Step Breakdown

1. Setup Firebase Project

• Go to Firebase Console.
• Create a new project.
• Enable Authentication (Email/Password or social logins).

2. Add Firebase to Your Web App

<script src="https://www.gstatic.com/firebasejs/10.0.0/firebase-app.js"></script>
<script src="https://www.gstatic.com/firebasejs/10.0.0/firebase-auth.js"></script>

• Configure with your Firebase keys.

3. Create Signup & Login Forms

<input type="email" id="email" placeholder="Email">
<input type="password" id="password" placeholder="Password">
<button onclick="signup()">Sign Up</button>
<button onclick="login()">Login</button>

4. Use Firebase Auth Methods

import { getAuth, createUserWithEmailAndPassword, signInWithEmailAndPassword } from "firebase/auth";

const auth = getAuth();

// Signup
function signup() {
  createUserWithEmailAndPassword(auth, email.value, password.value)
    .then(user => console.log("User Created:", user))
    .catch(error => console.error(error));
}

// Login
function login() {
  signInWithEmailAndPassword(auth, email.value, password.value)
    .then(user => console.log("Logged in:", user))
    .catch(error => console.error(error));
}

5. Authentication State Listener

onAuthStateChanged(auth, user => {
  if (user) {
    console.log("User is logged in:", user.email);
  } else {
    console.log("No user is logged in");
  }
});

6. (Optional) Add Firestore/Realtime DB

• Store user profiles, preferences, or activity logs.

7. Deploy Your App

• Use Firebase Hosting, Netlify, or Vercel.