Cookies are commonly used to store small snippets of information on the client-side. When making asynchronous requests with AJAX in JavaScript, it may be necessary to include cookies for authentication or other purposes. This blog post will guide you through the process of sending cookies with AJAX requests using pure JavaScript.

AJAX Basics

Before diving into cookie handling, let’s quickly review the basics of AJAX. AJAX stands for Asynchronous JavaScript and XML, and it allows us to make HTTP requests from the client-side without needing to reload the entire page. Here’s a simple example of an AJAX request using the XMLHttpRequest object:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://example.com/api/data', true);
xhr.onload = function() {
  if (xhr.status === 200) {
    // Handle the response
    var response = JSON.parse(xhr.responseText);
    console.log(response);
  }
};
xhr.send();

This code snippet makes a GET request to retrieve JSON data from https://example.com/api/data.

Including Cookies in an AJAX Request

To include cookies in an AJAX request, we need to set the withCredentials property of the XMLHttpRequest object to true. This property indicates that cookies should be included in the request. Here’s an example:

var xhr = new XMLHttpRequest();
xhr.open('GET', 'https://example.com/api/data', true);
xhr.withCredentials = true; // Include cookies in the request
xhr.onload = function() {
  if (xhr.status === 200) {
    // Handle the response
    var response = JSON.parse(xhr.responseText);
    console.log(response);
  }
};
xhr.send();

By setting xhr.withCredentials = true, the browser will include any relevant cookies in the request headers.

Summary

In this blog post, we explored how to send cookies with AJAX requests in JavaScript. By setting the withCredentials property of the XMLHttpRequest object to true, we can include cookies in the request headers. This is useful for scenarios where authentication or session information is stored in cookies. Incorporating cookies in AJAX requests allows for seamless interoperability between the client and server, enabling secure and authenticated data exchange.

#JavaScript #AJAX