As more and more web applications rely on session-based authentication, it becomes crucial to handle session expiration gracefully to provide a seamless user experience. In this blog post, we will explore different approaches to handle session expiration in JavaScript.

Approach 1: Polling to check session status

One common approach is to periodically send an AJAX request to the server to check the status of the session. If the session has expired, the server will respond with a specific status code or error message. JavaScript can then redirect the user to the login page or display a popup prompting them to login again.

// Polling function to check session status
function checkSessionStatus() {
  setInterval(function () {
    // Send AJAX request to the server
    $.ajax({
      url: '/session-check',
      type: 'GET',
      success: function (response) {
        // If session has expired
        if (response.status === 'expired') {
          // Redirect to login page
          window.location.href = '/login';
        }
      }
    });
  }, 300000); // Check every 5 minutes
}

// Call the function to start polling
checkSessionStatus();

Approach 2: JavaScript-based session countdown

Another approach is to use JavaScript to show a countdown timer indicating the remaining time until the session expires. When the countdown reaches zero, JavaScript can perform a specific action, such as redirecting the user to the login page or displaying a session expiration message.

// Countdown function
function sessionCountdown(minutes) {
  let seconds = minutes * 60;
  
  // Display the initial countdown
  document.getElementById('countdown-timer').textContent = `Session expires in ${minutes} minutes`;
  
  // Start the countdown
  let countdown = setInterval(function () {
    // Update the countdown display
    document.getElementById('countdown-timer').textContent = `Session expires in ${minutes} minutes ${seconds} seconds`;
    
    // Decrease the remaining time
    seconds--;
    
    // If the session has expired
    if (seconds < 0) {
      // Stop the countdown
      clearInterval(countdown);
      
      // Perform an action, like redirecting to login page or displaying expiration message
      // ...
    }
  }, 1000);
}

// Call the function to start the countdown (assuming session lasts for 30 minutes)
sessionCountdown(30);

Conclusion

Handling session expiration in JavaScript is crucial for maintaining a good user experience. In this blog post, we explored two common approaches - polling to check session status and using a JavaScript-based countdown. These approaches can be adapted and customized based on specific application requirements. By implementing a robust session expiration handling mechanism, you can ensure that your users are seamlessly guided to log back in when needed.

#sessionexpiration #javascript