How to delete cookies in php

Delete Cookie

When a cookie is created, if its validity time is not set, 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. These two methods are the same as setting cookies. They also call setcookie() Function to achieve the action of deleting cookies: No. One way is to omit all the parameter columns of the setcookie() function and only use the first parameter Cookie identification name parameter to delete the cookie data with the specified name; the second way is to use the setcookie() function to set the target cookie to "Already Expired" status.

1. Use the setcookie() function to set the target cookie to the "expired" state to delete the cookie

The basic types of ways to delete cookies and create cookies, also use setcookie() to delete cookies 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 the expiration time is set, the browser will save the cookie to the hard disk, and it will still be valid when the browser is opened 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.

The above is the detailed content of How to delete cookies in php. For more information, please follow other related articles on the PHP Chinese website!