Shulou(Shulou.com)06/03 Report--

This article mainly shows you the "sample analysis of the running process of PHP programs", which is easy to understand and well-organized. I hope it can help you solve your doubts. Let the editor lead you to study and study the "sample analysis of the running process of PHP programs".

HTTP Protocol and trigger of PHP script

HTTP is a Request/Response-based protocol that supports the operation of Web. The client of HTTP sends Request

To the server side, the server side returns Response. The Request contains the file name of the page that the client needs to access. The server returns the web page that the file name points to. If PHP, JavaScript, and so on are not used, the HTTP protocol transfer can only be static HTML files. That is, the HTML file is not affected by the user's behavior, and the content remains the same.

If you want to implement a dynamic web page, you need to use PHP or JavaScript. PHP is a programming language for server-side, and JavaScript is a programming language for client-side.

The PHP code is executed on the server side. When a user visits a web page that contains PHP code, it sends a Request to the server, which contains the file name of the web page. After receiving the Request, the server finds the file pointed to by the file name and finds that there is a PHP code embedded in it. It will call the PHP interpreter to process the file, and then organize the processed results to Response and send them to the client. PHP code can interact with server-side databases or other resources, or generate different pages depending on the user's actions.

Therefore, the PHP script is triggered when the server receives the client's Request. After receiving a Request, the server triggers a PHP script; after processing the script, it returns the result to the client and waits for the next Request. When the next Request is received, the server triggers another (or the same) PHP script. The two PHP script runs are independent of each other, and the second script run is almost unaffected by the previous script run.

JavaScript code is generally executed on the client side, that is, processed by the browser. The client gets the JavaScript code from the server, not the result of the code being executed, and then invokes the interpreter to execute the code.

Code block of PHP

PHP code can be embedded in HTML files, and you can often see blocks of PHP code scattered everywhere in HTML files. I have also been confused about the relationship between different blocks of PHP code in the same HMTL file. It turns out that PHP ignores HTML code between two blocks of PHP code.

Test PHP Multiple Blocks

This is HTML code.

This is HTML code too.

There are two blocks of PHP code in the code, which are separated by HTML code. The first PHP code block declares a variable $var; and the second code block references $var to change its value. Execute the above code with PHP, and the output is as follows.

Test PHP Multiple Blocks

This is HTML code.

This is PHP code block 1. $var=1

This is HTML code too.

This is PHP code block 2. $var=2

The second code block can refer to $var. Although separated by the HTML code, the execution of the two pieces of code completely ignores the HTML part. The output of PHP is the same as the following PHP code that is not separated by HTML, the former just inserts the corresponding HTML code between the PHP output.

The above is all the contents of the article "sample Analysis of the running process of PHP programs". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.