PHP
PHP stands for “Personal Home Page Tools” and is a scripting language. PHP is also assigned the meaning of Hyperlinks Preprocessor. The first PHP version was developed in 1994. The latest and most recent development is version 5, which was released in 2004. Programs coded with this scripting language and stored as a plain text file are interpreted into machine code by the web server at the time of invocation. Thus, PHP programs are largely platform-independent and can run on different hardware systems.
Programming PHP
PHP is a server-side scripting language that only needs to be installed on the web host’s server. A PHP parser is installed on the server, which reads the commands and sends to the visitor only the result. Every visitor of the website has the possibility to use all functions of the website with any browser. Additionally an editor is needed. For this purpose there are special PHP editors, in which the code can be written and then saved as a text file. Furthermore, an FTP client is needed to upload the finished pages to the website. There are three basic rules to follow when programming this scripting language, which can be easily learned. First of all, PHP must be inserted into HTML. HTML tags are sent from the server to the browser unchanged. Before the result can be sent to the browser, the code must be interpreted by the PHP parser on the server. The server must recognize where the PHP code is located and can be passed to the parser for processing. For this process a marking is necessary. The marking is done by “” at the end of the respective code section. PHP and HTML can also alternate several times. If this is the case, it is necessary to mark each section with ““. The second rule to follow is that each PHP application must be terminated with a semicolon. Ending with the semicolon is necessary for the PHP parser to recognize where the statement ends. The last rule to follow is that PHP files must be tagged. An HTML file (HTML page) that contains PHP must be marked accordingly, otherwise the PHP commands cannot be executed. Therefore, the file must end with “.php” and not with “.html” or “.htm”.
Application of PHP
This scripting language is used in the programming of dynamic websites. For example, discussion forums, guest books, visitor counters, forms with the processing of contact data , chats, blogs, image services, surveys, wikis, auctions, small games, can be programmed quickly and easily.
