1. Introduction

In this tutorial, we will learn how to set up an authentication system for an HTML application. We will cover form inputs, server-side scripts, and how to secure access to your application.

By the end of this tutorial, you will be able to create a simple authentication system that verifies user credentials, maintains user sessions, and protects sensitive data.

Prerequisites:

• Basic knowledge of HTML, CSS, JavaScript.
• Familiarity with Node.js and Express.js.
• Basic understanding of HTTP requests.

2. Step-by-Step Guide

Authentication:

Authentication is the process of verifying who a user is. When users enter their credentials, the system checks whether the entered details match the ones in the database. If they match, the user is authenticated.

Session Management:

Once a user is authenticated, the user's session needs to be managed so that the user remains logged in while navigating through the application. This is usually done by creating a session and storing it in a cookie.

3. Code Examples

Example 1: Creating Form Inputs

We will use HTML to create a simple login form.

<form id="loginForm">
  <label for="username">Username:</label><br>
  <input type="text" id="username" name="username"><br>
  <label for="password">Password:</label><br>
  <input type="password" id="password" name="password"><br>
  <input type="submit" value="Submit">
</form>

In this code snippet, we create a form with two input fields: one for the username and one for the password. The type="submit" on the last input field creates a submit button.

Example 2: Setting Up Server-Side Scripts

We will use Node.js and Express.js to set up the server-side scripts for handling the login.

const express = require('express');
const app = express();

app.use(express.json());

app.post('/login', (req, res) => {
  const { username, password } = req.body;

  // Authentication logic here

  res.send('Login successful!');
});

app.listen(3000, () => console.log('Server started on port 3000'));

4. Summary

We covered the basics of setting up an authentication system for an HTML application. We learned how to create a login form and set up server-side scripts using Node.js and Express.js.

Next, you can learn about password hashing for secure storage and how to implement authorization after authentication. You can visit MDN Web Docs for more resources.

5. Practice Exercises

Exercise 1: Create a registration form with fields for the username, password, and email.

Exercise 2: Set up server-side scripts to handle the registration form data.

Exercise 3: Implement a way to handle incorrect login credentials.

Remember, practice is key to mastering these concepts. Happy coding!