What Are Cookies? How Do Cookies Work?

HT Vũ Ngọc 02 May, 2025 Google Marketing

Small files known as computer cookies are used by web servers to store your browsing information. This allows websites to remember your device, your browser configuration, and associate it with your online activity.

A persistent cookie can store data for a period of time. These cookies allow usernames and passwords to be saved on the internet.
Data collected by third parties is used to send to website owners who want to improve advertising targeting.

After closing the browser, the session is deleted immediately. Session cookies are known for allowing you to keep items in your shopping cart even when navigating to a different page.

Are Cookies Safe?

Because cookies do not change as they travel back and forth, they cannot deliver viruses or malware to your computer under normal use. There is no way for a cookie to alter how your computer works.

See more products: Buy advertising accounts

However, some viruses and malware can disguise themselves as cookies to infiltrate your system. If you’re not careful, running or installing such programs can infect your PC immediately.
This is why many people want to know how to delete cookies from their browsers. A detailed guide is provided below.

How Cookies Transmit Data

Here is how data is transmitted:

A user accesses a website URL; the browser sends a request to the website.
The browser starts to locate the website’s homepage to respond to the user. During this stage, if the browser finds a previously set cookie file, it sends all the name-value pairs in that file to the server at the requested URL.
If the file is found and sent, the website server receives the data and the homepage request. At this point, the server can use the name-value pairs for specific purposes.
If no name-value pairs are received, the website administrator knows that the user is visiting the site for the first time. A new name is created for the user in the site’s database, and the server sends name-value pairs to the user’s computer in the response header. These pairs are stored on the computer’s hard drive.
When you revisit the site, the server may modify or add new name-value pairs.

Open the browser you are using.
Navigate to the location where cookies are managed in the browser settings. This option varies for each browser but is usually found under “Settings.”
Each browser provides options to enable or delete cookies. Generally, you can simply choose “Clear browsing data” to delete them. For more management options, select “Clear cookies and other site data.”

As you can see, most browsers are expanding their capabilities to let users control data and who can access it. While blocking all browser cookies may make navigation more difficult, it provides greater privacy in return.

Cookies were introduced to help website administrators manage websites more easily. Essentially, they allow websites to store state information on your computer. With this information, a website can remember your browser’s previous state.

An ID is a piece of state information, meaning that if an ID exists on your computer, the website knows you’ve visited it before. The status might be displayed as “Your browser has visited this site at least once,” and the website recognizes the access code from that visit.

1. Identifying the Number of Visitors

A unique way for websites to count visitors is by assigning a cookie to each visitor. With cookies, websites can determine:

How many visitors they receive
The number of new vs. returning visitors
How frequently a user visits the site

Websites achieve this using data. When a user visits the site for the first time, the site creates a new account in its database and assigns a cookie to the user. The site can then track how often the user visits by incrementing the associated visit counter in the database.

2. Storing Customer Characteristics

Websites can store user preferences to distinguish between customers. This means it allows customization. For example, you can visit msn.com and change the content, layout, and color scheme.

Additionally, it allows you to enter a zip code and find weather forecasts for specific areas. When you enter the zip code, a name-value pair is added to MSN’s cookie file.

See more products: Buy advertising accounts

3. Used for E-Commerce Websites

Additional functions include selecting shopping cart and checkout options. An ID provided by a cookie allows the website to identify you when you want to add something to your cart. Each item you add to your cart is saved in the website’s database, along with your ID value.

By retrieving all the necessary information from the database, the website knows what’s in your cart when you proceed to checkout. A smooth shopping experience wouldn’t be possible without cookies.

While not a perfect mechanism, cookies enable certain features that wouldn’t be possible without them. However, the following limitations make cookies imperfect:

1. One Computer, Multiple Users

Multiple users often share a computer at home or in public spaces. Let’s say you purchase something online from a shared computer, such as one in a library.

The website you bought from will store a cookie on that computer, potentially allowing the next user to make purchases from the same site using your account information.

2. Multiple Users, Multiple Computers

Many users operate multiple computers each day. For example, I might have one computer at home, one at the office, and a laptop for business trips. Unless the website is designed to address this issue, I won’t have any cookies on the other two devices. From the website’s perspective, I’m a completely different user when accessing from each of those devices. This can be problematic for maintaining preferences.

The solution to this issue is discussed below, but it does require developers to anticipate and plan for such scenarios.

3. Cookies Being Deleted

When you encounter browser issues and contact support, the first thing they usually advise is to delete all temporary Internet files on your computer. All cookies are deleted during this process. When you revisit the website, it assigns a new cookie, which leads to:

Inaccurate visitor tracking (e.g., miscounting new vs. returning users)
Loss of saved user preferences

In fact, there is a workaround for this—although it takes more time—called the Login/Sign-up feature. If you lose your cookies, you can still recover your preferences by logging into your account using your username and password.

If you need the most reputable payment method and advertising account provider, you can message the fanpage buybm365.com-Ads to receive advice from HT Media. In addition, you can follow the articles. Latest articles related to our Digital Marketing.