Php stands for hypertext pre-processor, and is what is known as a server side scripting language. That is file that runs on the websites server and not on the user's pc.The server is where the website files are stored and the client is the pc that is viewing the site. Php well only run on a server that as php installed on it, you can not run a php file on your pc the same as you can an Html file.
Php is used to add dynamic contact to the website. It can track users around your site and output pages from just a click, by collecting the relevant information from a database and inserting into the page. One reason it as such popularity with web developers is it is so flexible and a powerful code, but not that difficult to learn.
Unless you have got a Php enabled server running on your pc you will not be able to do your own files. So let see it in action instead.
Another great use for php is to keep a track of the sites visitor from page to page. When the users name is known it can make the site a little bit more personal to them by showing there name on it. You will only get to do this from a member site with login so as to know the users name.
To track the user we add the name to a session this will stay active until the user closes the page down. If you entered your name in the box above, it will be stored as a session. Go back to the home page and you will see your name in red at the top of the page, this is not set for the entire site only the home page as example.
Lets do some maths now!
Now you have seen from this very small set of examples how php can help to bring life into your site, if there is any particular example you wish to see please use the contact form on the site to ask.