Published 13 June 2022 /

Why are Cookies Important for Web Development?

Eddie Lewis

By Eddie Lewis

Why Cookies Are Important

Cookies are both a necessary feature of the Internet and a source of privacy and security issues.

As a result, web developers must have a thorough grasp of how cookies operate. Read on to learn more about why cookies are important for web development and where to find web development classes in the UK.


Cookies were created in the mid-1990s by Netscape as a mechanism to save certain user information in the browser rather than needing the Web Server to do so.

What Is the Purpose of Cookies?

Note that HTTP is stateless, so it doesn't remember anything between requests and responses. Each request is treated as a separate connection by the server. The web server has no way of knowing if you've already logged in, specified a preferred language, or anything else.

Over the last two decades, cookie use cases have grown, and they are currently routinely employed for:

  • Ad Serving Activity Tracking
  • Personalisation
  • Session Administration (keep users logged in as they navigate between pages)
  • Shopping Carts

What Exactly Is in A Cookie?

A cookie is nothing more than text data that the browser saves and comprises the following information:

  • The actual data (e.g., id = 1034820810) in a name-value pair
  • An expiration date (in UTC/GMT format) specifies the cookie's lifespan. The cookie is removed once the browser is closed if no expiration date is specified.
  • The domain and path of the server to which it is connected. This limits the sites to which the cookie may be shared.
  • (Optional) Secure tells the browser that the cookie should only be sent over HTTPS.
  • (Optional) HttpOnly blocks any client-side code from accessing the cookie. This is used to avoid malicious scripts from stealing sensitive data such as sessions from cookies.

Where Are Cookies Stored in Browsers?

The location varies depending on the browser. Most current browsers employ an SQLite database file to store cookies on a disk.

Cookie Size Restrictions

  • The maximum cookie size varies by browser.
  • It's best not to exceed 50 cookies per domain and 4093 bytes per domain for general support.

Using JavaScript to Manage Cookies

  • The document.cookie property in JavaScript may be used to create, read, and remove cookies.
  • Remember that a cookie with the HttpOnly setting set will not be retrievable.
  • Because the property produces a string containing all of the cookies for that site, parsing a cookie with JavaScript can be a pain. You must split the string, keeping in mind that a semicolon separates cookies.

Session Cookies

There is no expiration date on a session cookie. These cookies are kept in memory rather than being written to disk. The cookie is erased when the browser is closed.

Some typical session ID names from major web application servers are shown below:

  • ASP.NET_SessionId (ASP .NET)

Persistent Cookies

A persistent cookie has an expiration date. When a person closes their browser, they are not deleted.

First-Party Cookies

A first-party cookie may only be used on the same domain as your website. A first-party cookie, for example, would only be accessible by pages inside if you were browsing the site.

Third-Party Cookies

Only the domain from which the browser obtains content can set cookies. On the other hand, most commercial websites integrate material from other websites in the form of advertisements.

The browser will also collect material from an ad network like Google DoubleClick when visiting This allows DoubleClick to create its cookie in your browser to track which advertisements you've seen.

Advertising networks, search engines, and social networking sites regularly employ third-party cookies to monitor users. If you want to know more, you can also enrol yourself in web development learn online.


Internet cookies may help you operate a better website and offer useful business insight if you utilise them correctly and follow the relevant privacy standards. When you utilise cookies on your website, you can give your visitors a more personalised and smoother experience. The useful data they collect while tracking user behaviour may be crucial for improving your marketing approach and engaging with clients. Learn more through web development courses.

Professional Web Developers are on hand at Code Success to assist you in getting started on the path to a new career in web/software development. You may carve yourself your niche as a skilled web developer by taking advantage of our low-cost online courses and learning possibilities. Sign up for our web development classes in the UK today!