Discover where cookies are hiding

Recently, we often see various websites prompting us to accept cookies and understand how they are used. So, what are cookies? Where are they hiding? Let's explore the world of cookies together.

Simply put, a cookie is a text file that is stored on a user's computer by a website. It can store data about users such as login credentials, browsing history, and personalization settings. This data can be automatically loaded when users visit the website, thereby improving the user experience. In addition, cookies can also be used to track user activities and behaviors to optimize online advertising and marketing strategies.

However, the use of cookies is also controversial. Some people worry that cookies will invade their privacy or be used by hackers to steal sensitive information. Therefore, many browsers provide some security settings to help users control the use of cookies and protect their privacy.

So where are the cookies hiding? Let's see where they are with some code examples.

First, we can use JavaScript code to check all cookies in the current page. Enter the following code into the console:

console.log(document.cookie);

This will output all cookies stored on your computer by the current site. When we visit a website in our browser, the website stores one or more cookies on our computer. For example, on LinkedIn we can find the following cookies:

li_sugr= ; liap=true;...

These cookies usually have a name, a value and an expiration time and other attributes, and we can set or delete cookies through JavaScript. Here is some JavaScript code to set and delete cookies:

//设置cookie
document.cookie = "username=John Doe; expires=Fri, 31 Dec 2021 23:59:59 UTC; path=/";

//删除cookie
document.cookie = "username=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;"

In the above code, we use the document.cookie property to set and delete cookies. When setting a cookie, we need to specify the cookie's name, value, expiration time and other attributes. When deleting cookies, we only need to set the name of the cookie and the expiration time to the past time.

In addition, we can also use the browser's developer tools to view the cookies stored by a specific website. In Chrome, open the developer tools and switch to the "Application" tab. In the left navigation bar, click "Cookies" to view the cookies of the current page and their properties.

In general, cookies are a technology used to store user data and improve website usage experience. Although their use is somewhat controversial, we can control and manage their use by setting browser security options or using JavaScript code.

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