History of PHP
PHP was created in 1994 at the hands of Rasmus Lerdorf. PHP began as a set of CGI scripts developed to track views of his resume online. Rasmus continued adding scripts to his collection so he could do more with his websites. Over time, some friends began to use it as well.
By June 1995, enough of a framework was in place that Rasmus decided to make PHP public. As others embraced it, and began to submit their own work, PHP grew. By version 3 it was decided that the time had come for a more professional name. In homage to its original name of Personal Home Page, the PHP acronym was kept, but was changed to a recursive representation of hypertext preprocessor. PHP was now an independent language, with object-oriented capabilities, high extensibility, and had a growing following.
With strong semblance to languages like C++ and Perl, the goal was to create a language that allowed fast development of dynamic pages.
Server Side Langiage
Some advantages to server-side languages are that the code is hidden from the user, and secures what is taking place in the background. It also reduces the work load that the user’s computer is burdened with. However, this also means the server must be powerful enough to support the number of users requesting pages, as it must bear the brunt of the computation.
PHP is a parsing engine, which means it examines the php file, performs any php related tasks it finds, and passes the result to the web server. This makes it an interpreted language, as the output and script are run on demand, as opposed to a compiled language where the code is transformed and saved into a runnable form.
PHP File Extension and Code
PHP uses a special file format to identify its contents. When you want to use PHP in a file, you need to set the file format as .php.
The PHP code begin with <?php and end with ?>. These are tags, just like in HTML, and are used to mark the start and end of a section of code that contains PHP.