Can php cookies not be deleted?

In PHP, cookies can be deleted; you can set the validity period of the cookie to the current time to delete it, because deleting cookies requires ensuring that the validity period of the cookie is in the past before it can trigger the browser's deletion mechanism. The syntax is: "setcookie("Cookie_name", "" , time()-1);".

The operating environment of this article: Windows 10 system, PHP version 8.1, Dell G3 computer

Can php cookies not be deleted?

php cookie can be deleted

To delete a cookie, you need to ensure that its expiration date is in the past to trigger the browser's deletion mechanism.

The way to delete a cookie is to set the validity period of the cookie to before the current time

Delete Cookie

When the cookie is created, if there is no Set its validity time, and its cookie file will be automatically deleted when the browser is closed. If you want to delete the cookie file saved on the client before closing the browser, there are two methods. Like setting cookies, these two methods also call the setcookie() function to delete cookies: The first method is to omit setcookie. () All parameter columns of the function only use the first parameter Cookie identification name parameter to delete the cookie data of the specified name; the second method uses the setcookie() function to set the target cookie to the "expired" state.

1. Use the setcookie() function to set the target cookie to the "expired" state to delete the cookie. Working principle of linear motor

The basic types of ways to delete cookies and create cookies, delete cookies also Use the setcookie() function. To delete cookies, you only need to set the second parameter in the setcookie() function to a null value, and set the third parameter Cookie's expiration time to be less than the current time of the system.

Let’s use code to set the cookie expiration time to the current time minus 1 second.

setcookie("Cookie_name", "" , time()-1);

In the above code, the time() function returns the current timestamp expressed in seconds. Subtracting 1 second from the current time will get the past time, thereby deleting the cookie.

2. Use the setcookie() function to set the cookie's lifetime to empty by default. Then the lifetime is the same as the browser, and the cookie will be deleted when the browser is closed. Specify only one parameter, the cookie identification name, to delete the cookie data of this specified name in the client.

setcookie("Cookie_name");

Note: Set the expiration time to 0, or delete the cookie directly.

Cookie life cycle

If the cookie does not set an expiration time, it means that its life cycle is the period of the browser session. As long as the browser is closed, the cookie will disappear automatically. This type of cookie is called a session cookie and is generally not stored on the hard drive but in memory.

If you set the expiration time, the browser will save the cookie to the hard disk, and it will still be valid when you open the browser again, guiding its validity period to expire.

Although cookies can be stored in the client browser for a long time, they are not static. Because the browser is allowed to store up to 300 Cookie files, and each Cookie file supports a maximum capacity of 4KB; each domain name supports a maximum of 20 Cookies. If the limit is reached, the browser will automatically delete Cookie files randomly.

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