Creating a Secure Login Registration Form for Students Practice Project

<!-- The main container holding both registration and login forms -->
<div class="container">
  
  <!-- Registration Form Section -->
  <div class="registration-form">
    <h2>Register Now</h2>
    <!-- Form for user registration -->
    <div class="form">
      <input type="text" placeholder="email"> <!-- Email input field -->
      <input type="text" placeholder="password"> <!-- Password input field -->
      <input type="text" placeholder="confirm password"> <!-- Confirm password input field -->
      <button onclick="registerUser()">Register</button> <!-- Register button -->
    </div>
    <!-- Footer with a link to switch to the login form -->
    <div class="footer"> Already registered? <a href="#" data-btn-type="login">Login here</a></div>
  </div>

  <!-- Login Form Section -->
  <div class="login-form">
    <h2>Login</h2>
    <!-- Form for user login -->
    <div class="form">
      <input type="text" placeholder="email"> <!-- Email input field -->
      <input type="text" placeholder="password"> <!-- Password input field -->
      <button onclick="loginUser()"> Login</button> <!-- Login button -->
    </div>
    <!-- Footer with a link to switch to the registration form -->
    <div class="footer"> Not registered? <a href="#" data-btn-type="register" >Register now</a></div>
  </div>
</div>

/* Global styling for all elements */
* {
  box-sizing: border-box;
  transition: all 0.3s ease-in-out;
  font-family: arial;
}

/* Styling for the body */
body {
  display: grid;
  place-content: center;
  height: 100vh;
  background:linear-gradient(rgba(0,80,150,0.3),white);
}

/* Styling for the main container */
.container {
  box-shadow: 0px 10px 20px rgba(0, 0, 150, 0.3);
  position: relative;
  width: 80%;
  min-width: 400px;
  color: #fff;
  overflow: hidden;
}

/* Styling for both registration and login forms */
.registration-form, .login-form {
  padding: 20px;
  background: #005;
}

/* Styling for form elements */
.form {
  display: grid;
  gap: 20px;
}

/* Styling for the login form (initially positioned off-screen) */
.login-form {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 100%;
  height: 100%;
  left: -100%;
}

/* Styling for input fields and buttons */
input, button {
  padding: 10px 10px;
  border: none;
  outline: none;
}

/* Styling for input fields */
input {
  border-bottom: 2px solid black;
  background:linear-gradient(rgba(150,150,200,1),white);

}

/* Styling for buttons */
button {
  background: #ec0;
  color: #000;
  border-radius: 5px;
}

/* Styling for button hover effect */
button:hover {
  background: #fd0;
}

/* Styling for the footer */
.footer {
  padding: 10px;
  text-align: center;
}

/* Styling for footer links */
.footer a {
  color: #fd0;
  text-decoration: none;
}

// Array to store user data
let users = [];

// Retrieve previously saved user details from localStorage
if (localStorage.getItem("users") != null && localStorage.getItem("users") != undefined) {
  users = JSON.parse(localStorage.getItem("users"));
}

// Event listener for clicks on footer links
let footerLinks = $(".footer a");
footerLinks.click((event) => {
  // Determine which form to show based on the clicked link
  let showFormType = $(event.target).attr("data-btn-type");
  if (showFormType == "login") {
    console.log("Show Login form");
    showLoginForm();
  } else if (showFormType == "register") {
    console.log("Show register form");
    showRegistrationForm();
  }
});

// Function to show the login form
function showLoginForm() {
  $(".login-form").css({ left: "0%" });
}

// Function to show the registration form
function showRegistrationForm() {
  $(".login-form").css({ left: "-100%" });
}

// Function to register a new user
function registerUser() {
  let inputField = $(".registration-form input");
  let email = inputField[0].value;
  let password = inputField[1].value;
  let confirmPassword = inputField[2].value;

  // Validate user input and register the user
  if (email.length > 5 && password.length > 5 && password === confirmPassword) {
    users.push({ email: email, password: password });
    localStorage.setItem("users", JSON.stringify(users));
    showLoginForm();
  }
}

// Function to login an existing user
function loginUser() {
  let inputField = $(".login-form input");
  let email = inputField[0].value;
  let password = inputField[1].value;

  // Check if the user exists and display appropriate message
  if (isUserExist(email, password)) {
    alert("Welcome back " + email + "!");
  } else {
    alert("User not found!");
  }
}

// Function to check if a user with given credentials exists
function isUserExist(email, password) {
  let userExist = false;
  users.forEach((user, index) => {
    if (user.email.trim() === email.trim() && user.password.trim() === password.trim()) {
      userExist = true;
    }
  });
  return userExist;
}