PHP

PHP is the weapon of choice for many developers for creating dynamic web pages and applications. PHP is a dynamic scripting language that can be embedded in web pages. PHP is processed by the server, outputting normal HTML. Unlike client-side technologies such as JavaScript, PHP developers know their scripts will run with the capabilities they need.

Since it is open source, PHP is the preprocessor of choice on Unix systems running Apache. Indeed, PHP has been implemented as an Apache module and comes installed, but not activated, by default on Mac OS X.

To properly ensure PHP is installed, you need to have a PHP page. The best test page is a simple PHP Info page. It relies on PHP to be working, so it's a good test, and it gives you a lot of information about your PHP installation, so it's actually useful.