Using PHP For Interactive Web Pages - Introduction: What is PHP? | Mathematical Association of America

摘要

When I first started writing web pages, I found it frustrating that, while it was easy to create nice looking forms in plain HTML, it was much more difficult to set up my site to actually respond to (or even record) data submitted via a form. Fortunately, as the web has grown, so have the tools available to handle such tasks. Simple processing of form data is now reasonably easy and allows a web site to become much more interactive. In this article, I present an overview of PHP as one of the useful tools for adding interactivity to a web site beyond a set of hyperlinks. The name is one of those cute self-referential acronyms, the PHP Hypertext Preprocessor. While PHP is a full programming language, it is designed to make adding basic interactivity to a web page easier than it would be with Java applets or CGI programs. In particular, PHP makes it very easy to handle data submitted from a standard HTML web form. PHP code is embedded into a standard web page, where it is set off with tags. (Some variations are permitted on the exact syntax of the tags.) When a browser requests a PHP page from the server, the server scans the contents of the page, then runs the code in the tags and replaces the tags and their content with the output of the code before sending the page to the browser. Since the code is embedded directly into the page, PHP is fairly quick to write and easy to maintain. PHP is not the only language to use such a technique -- Microsoft's Active Server Pages and server-side JavaScript both work similarly. PHP is the open-source variation on this common theme.