What is PHP and how is it used?
PHP is a server side programming language and is by far the most used in the world of website design. According to many sources, including W3techs Web Technologies Surveys, it is used in nearly 80% of all websites on the web today. Though not the only choice, it is by far the most popular, and in my opinion the superior choice.
Sites that use PHP include Facebook, Yahoo and Wikipedia - I have complied a more complete list here.
PHP is currently in its 5th version (released in July of 2004) with PHP6 rumored to be right around the corner.
Its history dates back to around 1994 and was originally known as PHP/FI. It was created in 1994 by Rasmus Lerdorf. I wont get to deep into the history, if you are interested in that, please visit PHP.net's history of PHP. The website also contains a ton of information about how it is used and is backed by a very solid community. If I can give one peice of advise to anyone planning on developing websites it is to bookmark that site and visit it often.
PHP, as well as other server side languages, are used to process information on the computer hosting the website. This is indespensible for operations such as:
- interacting with databases
- sending email from your website
- using variables for your website
- building and facilitating login systems
- performing image processing (research GD libraries)
- uploading images, audio, video or other files
- anything else that needs to be done "behind the scenes"
Because PHP is as popular as it is, figuring out how to do certain things is often as easy as googling some other examples of what you are trying to acheive. Care must be applied however, many of the published scripts are not necessarily utilizing best practices. You can learn a lot from other peoples code but should not make a practice of simply copying and pasting what you find as this can lead to serious security implications. If you find a good example of what you want to do, do not imploy this strategy until you full understand what is going on. Hopefully I will be of some assistance with that.