A server sided scripting language that was specifically developed with the web in mind.

What can PHP be used for?

If you've seen a form on the Internet, much like my "Get a Quote" page or Google's search box, you can be pretty much assured that it uses a server side scripting language like PHP.

PHP allows for a range of functions such as allowing web surfers to customise the appearance of a website in their browser, the creation of photo albums on a sever or the ability to manage searchable databases and a whole lot more to boot.

If you can conceive it PHP can create it!