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Mastering HTTP Cookies: A Comprehensive Guide with JavaScript Management

Introduction to HTTP Cookies

The Internet has revolutionized the way we live our lives and has made it easier for us to communicate, work, and socialize. Essential to our experience on the web are HTTP cookies tiny bits of information that are stored on our devices when we visit websites.

Cookies play a vital role in the functioning of the internet, and it would be challenging to browse the internet without them. This article will provide a comprehensive overview of HTTP cookies, their purposes, and how to manage them with JavaScript.

Well explore the definition and function of HTTP cookies, the purposes of using cookies, the details of a cookie, how to retrieve and set a cookie value, and how to remove a cookie.

Definition and Function of HTTP Cookies

HTTP Cookies are small text files that are stored on a user’s web browser when they visit a website. These cookies are used to store information about the user, such as their preferences, session data, and other relevant details.

Cookies are created by server-side scripts that send them to the user’s web browser, where they are stored in a special folder. Every time the user visits the same website, these cookies are sent back to the server along with any later requests made by the user, allowing the website to recognize them and tailor their experience accordingly.

Purposes of Using Cookies

Cookies serve several purposes on the internet, each of which contributes to an overall better user experience. Here are the three most common purposes of using cookies:


Session Management – Cookies are used to manage user sessions, allowing the user to browse a website while maintaining their session status. For example, when you visit an online shopping store and add items to your shopping cart, the website stores that item in a cookie, allowing you to continue shopping without losing your cart items.

2. Personalization – Cookies can be used to personalize a user’s experience.

For example, if you sign in to your email account, the website will store a cookie to remember your login details, allowing you to access your account without needing to sign in again. 3.

Tracking – Cookies can be used to track user behavior on a website. For example, when you visit a social media website, the website stores a cookie that tracks the pages you visit, recommending posts that align with your interests.

Details of a Cookie

HTTP Cookies consist of several factors, including:

1. Name – The name identifier for the cookie.

2. Value – The data stored in the cookie.

This data is typically a string of characters. 3.

Domain – The domain name that the cookie is valid for. This can be an entire domain, such as www.example.com, or a subdomain, such as www.blog.example.com


Path – The path on the domain that the cookie is valid for. For example, /blog.

5. Expiration – The expiration date of the cookie.

6. Secure Flag – This flag is used to indicate that the cookie should only be sent over HTTPS.

Managing Cookies with JavaScript

If you want to manage cookies using JavaScript, here are three main methods you can use:

1. Retrieving a Cookie Value – To retrieve a cookie value, use the document.cookie property, which returns all the name-value pairs for a particular cookie.

Note that the data returned from document.cookie is URL-encoded, so you need to decode it to use it. You can do this by using the built-in JavaScript function decodeURIComponent().

2. Setting a Cookie – To set a cookie, use the document.cookie property.

The syntax for setting a cookie is as follows:

document.cookie = “name=value; domain=example.com; path=/; expires=Wed, 26 May 2022 01:00:00 GMT; secure”;

In this example, the name of the cookie is name, and the value is value. The cookie is valid for the domain “example.com” and the path “/”.

It also expires on May 26th, 2022, and has the secure flag set, indicating that it should only be sent over HTTPS. 3.

Removing a Cookie – To remove a cookie, you can use the same syntax for setting a cookie, but with an expiry date of 0, which will make the cookie expire immediately. For example:

document.cookie = “name=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/; domain=example.com; secure”;

This sets the name of the cookie to an empty string and expires it immediately.


HTTP Cookies are ubiquitous on the internet, and they play a vital role in providing users with a personalized and efficient browsing experience. While they have received some criticism for their ability to track users, cookies remain a fundamental aspect of web technology.

By using JavaScript, users can manage cookies to enhance their experiences while browsing the internet.

3) Using the Cookie Class in JavaScript

In addition to the basic functions of setting, retrieving, and removing cookies in JavaScript, we can also use a cookie utility class that provides static methods to make handling cookies even easier. This class, simply called the Cookie Class, is defined in JavaScript libraries and can be imported to use its functionality in your script.

The Cookie Class generally provides methods like set(), get(), and remove(). These methods allow you to set a new cookie value or update an existing one, retrieve a cookie value that has already been set, and remove a cookie value as well.

Here is an example of how to use the Cookie Class to set, retrieve, and remove a cookie:


// import the Cookie Class from the utility library

import { Cookie } from ‘utility-library’;

// set a new cookie with the name “username” and value “John”, valid for 1 day

Cookie.set(‘username’, ‘John’, 1);

// retrieve the value of the “username” cookie

const usernameValue = Cookie.get(‘username’);

// remove the “username” cookie



In this example, we import the Cookie class from a utility library. Then, we use the set() method to set a new cookie with the name “username” and value “John,” which will remain valid for one day.

We then use the get() method to retrieve the value of the “username” cookie and assign it to a constant called “usernameValue.” Finally, we use the remove() method to remove the “username” cookie. You can also use the Cookie Class methods to implement more complex functionality in your web application.

For example, you can use the set() method to set a “isAdmin” cookie for users who are administrators:


// set a new cookie with the name “isAdmin” and value “true”, valid for 1 day

if (userRole === ‘admin’) {

Cookie.set(‘isAdmin’, true, 1);



You can then use the get() method to retrieve the value of the “isAdmin” cookie and determine whether a user is an administrator:


// retrieve the value of the “isAdmin” cookie

const isAdmin = Cookie.get(‘isAdmin’);

if (isAdmin) {

// display admin-only content



4) Viewing Cookies in Web Browsers

Web browsers provide a convenient way to view and manage cookies that have been set by websites. The most common way to access cookies in a web browser is through the developer tools.

To access cookies in the developer tools, open the developer console by pressing F12 or Ctrl + Shift + I on Windows, or Command + Option + I on Mac. Then, go to the Application tab in the console and expand the Cookies node.

You should see a list of cookies that have been set by the website. In addition to viewing the cookie name and value, you can also see the domain and path for each cookie, as well as its expiration date and whether it is secure.

Here is an example of what cookies might look like for the website Google.com:

![Google Cookies](https://www.htmlgoodies.com/wp-content/uploads/2021/05/google-cookies.png)

As you can see, Google sets a number of cookies for various purposes, including tracking user behavior and personalizing the user experience. It is important to note that cookies can be cleared or deleted at any time by the user or the website, and that cookies are often used in conjunction with other tracking technologies like pixel tags and browser fingerprinting.

As such, cookies are just one small piece of a larger puzzle when it comes to user privacy and online tracking. HTTP cookies are integral to the functioning of the internet, serving multiple purposes such as session management, personalization, and tracking.

Their structure consists of a name, value, domain, path, expiration, and a secure flag. Cookies can be managed using JavaScript, either through basic functions or by utilizing a Cookie Class with set(), get(), and remove() methods.

Web browsers allow users to view and manage cookies through the developer tools. As cookies continue to play an essential role in the online experience, implementing responsible cookie management is crucial for user privacy.

By understanding HTTP cookies and how to manage them, users can enhance their browsing experience while also protecting their privacy.

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