How cookies work

The working principle of cookies involves the server sending cookies, the browser storing cookies, and the browser processing and storing cookies. Detailed introduction: 1. The server sends a cookie, and the server sends an HTTP response header containing the cookie to the browser. This cookie contains some information, such as the user's identity authentication, preferences, or shopping cart contents. After the browser receives this cookie, it will be stored on the user's computer; 2. The browser stores cookies, etc.

Operating system for this tutorial: Windows 10 system, Dell G3 computer.

A cookie is a small file that stores data in a web browser. It is sent to the browser by the server and stored on the user's computer. The working principle of cookies involves communication between the browser and the server, as well as the browser's processing and storage of cookies.

When a user visits a website, the server will send an HTTP response header containing a cookie to the browser. This cookie contains some information, such as the user's identity authentication, preferences or shopping cart contents. After the browser receives this cookie, it will be stored on the user's computer.

Every time the user visits the website again, the browser will send the stored cookie to the server. By checking the information in the cookie, the server can identify the user and provide personalized services. For example, if the user selected the "remember me" option during their last visit, the server can automatically log in the user through a cookie.

The working principle of Cookie also involves the attributes and domains of Cookie. Cookies can have an expiration time set, and when the expiration time arrives, the browser will automatically delete the cookie. Cookies can also set domains to specify which websites can access the cookie. This can limit the scope of use of cookies and increase security.

In addition to cookies sent by the server, browsers can also create and manipulate cookies through JavaScript. Through JavaScript, websites can store some temporary data on the user's computer, such as the user's choices or browsing history. These cookies are often called "session cookies" because they are only valid during the user's session and are deleted when the browser is closed.

The working principle of cookies also involves the processing and storage of cookies by the browser. The browser stores cookies in specific folders for quick access when needed. Browsers also provide APIs that allow developers to read and write cookies through JavaScript.

Although cookies play an important role in web development, they also have some problems. First, cookies are stored on the user's computer and may be exploited by malware or hackers. Secondly, the use of cookies may violate users' privacy. To solve these problems, browsers provide some security mechanisms, such as same-origin policy and privacy mode.

In general, cookies are a mechanism for storing data in web browsers. It implements functions such as user identity authentication, personalized services, and temporary data storage through communication between the browser and the server. The working principle of cookies involves the server sending cookies, the browser storing cookies, and the browser processing and storing cookies. Although cookies have some problems in web development, they are still an important technology.

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