Detailed examples of basic usage of php cookie and session

A cookie is a piece of information sent by the web server to the browser. The browser stores cookies for each web server in a local file. In the future, when the browser sends a request to a specific web server, it will also send all cookies stored for that server.

Session is another mechanism for recording client status. The difference is that the cookie is saved in the client browser, while the session is saved on the server. When the client browser accesses the server, the server records the client information on the server in some form, which is called a session. When the client browser visits again, it only needs to find the customer's status from the session.

Cookie is the traditional session control. Since the information to be stored is stored on the client, the security factor is low, while session session control stores the information to be stored on the server, so compared to cookies The safety factor is high.

Whether it is stored in cookie mode or session mode, there must be no output statement before using the stored function, otherwise an E-level error will occur.

Using cookie storage method

setcookie('cookie_name','cookie_value',cookie_time);

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Use session storage method

session_start());

When the user executes the session_start() function once, a session_id() will be generated. This session_id() will be copied and one copy will be used as a file. name, is saved on the server, and is saved as a string under the session_name() file of the client. When the user executes sessio_start() for the second time, the user comes with his own session_id(), and then when the user executes sessio_start() for the second time, When we need to use the session, the client will use its own session_id() to find the session_id() on the server that matches the session_id() it has, and then open the file.

The following is index.php

The following is index_a.php

'; echo $_SESSION['age']; }else{ header("location:index.php");//如果不存在session则跳转到页面index.php } ?>

Then after we register a session we How to delete this conversation?

The following is the code to delete the session

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