1. Understand session_register_shutdown() session_register_shutdown() is a function provided by PHP. Its function is to automatically call session_write_close() when the script is executed to ensure that session data is correctly written to storage. It is often used to prevent developers from forgetting to manually close sessions resulting in data loss, especially in complex logic.

Session is an important means to implement user state management. Through the session, the server can save user data between different requests. However, in some cases, PHP's session data may be incomplete or not written correctly, especially if an exception or premature termination occurs during script execution. To solve this problem, PHP provides the session_register_shutdown() function, which ensures that session data is properly saved when the script is executed.

In web application development, the security of user login verification is particularly important. PHP provides a variety of encryption methods, and the crypt() function is popular for its simplicity and support for multiple encryption algorithms. This article will introduce in detail how to combine the crypt() function and PHP session function to achieve a secure login verification function.

When developing PHP website applications, we often need to dynamically display the data obtained from the database to the front end, and we hope that after the user refreshes or leaves the page, this data can be stored persistently to prevent loss. This can be achieved very easily by combining the mysqli_result function with PHP's Session storage. This article will introduce in detail how to use these two for dynamic display and persistence of data.