The personal homepage hypertext preprocessor (PHP) is a programming language that was designed to provide a means for creating dynamic web content that could be viewed inside a web browser. The language has since expanded, allowing fully functional PHP applications to be deployed both on web servers and on regular computers. PHP applications primarily are geared toward functions that involve database access, such as search engines, e-commerce and advertising. They also can be used for inter-browser communications and games without the need for a dedicated server separate from the web server. Social media sites, electronic forums and remote access for businesses and educational institutions are all examples of where PHP applications are regularly deployed.
One of the abilities of PHP applications that makes them attractive for certain uses is the ability to interface easily with a relational database. This means information from a large business can be placed in a standardized database format and accessed online through a program written in PHP through a website. Using PHP with a database removes the need for customized interfaces that might be incapable of scaling with the needs of a business.
This same database functionality has made PHP applications one of the most used in the realm of e-commerce as of 2011. PHP can be used to access and display products that are compiled into a database, and also to retrieve customer information in a secure way through the same process. Similarly, PHP can be used as a gateway, acting as an intermediary between a secure payment processing system and the user or web server.
Through the use of cookies and remote databases, PHP applications can be employed by marketing agencies to deliver customized advertising content directly to users. This means banners and other advertisements on websites can be tailored to the person viewing them based on previous information gathered from the web. Using PHP makes it possible to seamlessly access this information and to use it to choose what advertisements should be displayed.
PHP applications can be designed to run on the web server being accessed by a user, so they can be used in ways that some other scripting languages cannot. User forums, comment lists and all their related functionality — such as custom avatars or signatures — can be implemented through the use of PHP applications. One benefit of using PHP for these features instead of other languages is that the application is run almost completely on the server side, ensuring a high level of security and a minimal load on the client system and web browser.