What is PHP?

PHP (Hypertext Pre-processor) is a scripting language that allows the creation of dynamic web pages.

In contrast to normal html pages, where the content is static, PHP can be used to enhance your website by allowing you to present different content in your web pages depending on the situation.  For example, you may wish to provide different information to visitors that have logged in, than you would to guests.  You may also wish to provide the ability for visitors to add articles to your site or to add comments to articles that you have published. 

PHP could also be used to create a page that allows orders to be taken from your website, and emailed to your sales team, while the order and customer details are saved in a database.

These are just a few possibilities, however the flexibility of PHP provides virtually limitless opportunities, which is why it is one of the most popular languages for writing web based applications.