How To Restrict Html Page With Login Authentication C

Have you ever wanted to restrict access to certain HTML pages on your website and require users to login before they can view the content? In this article, I will guide you through the process of implementing login authentication for your HTML pages using the programming language C.


As a web developer, I understand the importance of protecting sensitive information or exclusive content on a website. By adding login authentication to your HTML pages, you can ensure that only authorized users can access certain pages or perform specific actions.

Implementing login authentication might sound complex, but with the right approach, it can be accomplished effectively. In this article, I will walk you through the step-by-step process of restricting HTML pages with login authentication using C programming.

Step 1: Setting Up the Login Page

The first step is to create a login page where users can enter their credentials (username and password). This page will contain a form with input fields for username and password, and a submit button.

Here’s an example of a basic login form in HTML:

<form action="login.php" method="POST">
  <label for="username">Username:</label>
  <input type="text" id="username" name="username" required>
  <label for="password">Password:</label>
  <input type="password" id="password" name="password" required>
  <input type="submit" value="Login">

Make sure to replace the form’s action attribute (login.php) with the appropriate file where you’ll handle the login authentication process.

Step 2: Handling the Login Authentication in C

Now, it’s time to handle the login authentication using C programming language. In this step, we’ll create a C program that will receive the submitted credentials from the login form and validate them against a predefined list of authorized users.

Here’s an example of a C program that performs the login authentication:

#include <stdio.h>
#include <string.h>

int main() {
  char username[20];
  char password[20];

  printf("Enter username: ");
  scanf("%s", username);
  printf("Enter password: ");
  scanf("%s", password);

  // Check if the username and password are valid
  if (strcmp(username, "admin") == 0 && strcmp(password, "password") == 0) {
    printf("Login successful! You can now access restricted content.");
  } else {
    printf("Login failed! Please try again.");

  return 0;

In this example, we’re comparing the entered username and password with the values “admin” and “password” respectively. You’ll need to modify this code to match your own list of authorized users or connect it to a database for user authentication.

Step 3: Restricting Access to HTML Pages

Now that your login authentication is working, you can proceed to restrict access to specific HTML pages based on whether a user is logged in or not.

To achieve this, you can add a piece of code at the beginning of each restricted HTML page to check if the user is logged in. If not, you can redirect them to the login page. Here’s an example:

#include <stdio.h>
#include <stdlib.h>

int main() {
  // Check if the user is logged in
  if (!isUserLoggedIn()) {
    return 0;

  // Render the restricted HTML content

  return 0;

In this example, the functions isUserLoggedIn(), redirectToLoginPage(), and renderRestrictedContent() are placeholders, and you’ll need to implement them according to your specific requirements.


Implementing login authentication for your HTML pages using C programming can help you protect sensitive information and restrict access to exclusive content. By following the steps outlined in this article, you’ll be able to add an extra layer of security to your website.

Remember to always prioritize the security of your users’ data and consider implementing additional security measures such as encryption and secure connections (HTTPS) to further enhance your website’s security.

For more information or further assistance, feel free to visit our Login Authentication Guide.