Question: Aren't all web pages originally placed on the server? Even HTML pages stored in the. html file?
Answer: Yes, all the files on the site are stored on the server, HTML, CSS, PHP, etc., however, they are not all processed by the server, HTML and CSS files and image files are sent directly to the client browser, without manipulating what specifically contains. PHP files are different because the PHP file contains code that is to be processed by the WEB server and run on the server. Instead of sending the PHP code to the browser, it sends the result of running the PHP code to the browser, which is pure HTML and CSS.
Question: Submitted form, file name is report.php, server (Apache) How do you know where to find this report.php file?
Answer: PHP files are always put together with HTML files on a Web server, and there is nothing special about how to place PHP scripts on a Web server, just upload them to a location that the Web page can access. It is usually placed under the Htdocs directory under the root directory.
The escape character \, only works in double quotes.
In PHP, single and double quotes are a bit like Linux, for example, variables can be recognized inside single quotes, and escaped characters cannot be identified.
Headfirst PHP & MySQL