Hypertext Preprocessor (PHP)
PHP is a script language and interpreter and is mainly used on Linux Web servers. PHP is freely offered and originally derived from Personal Home Page Tools.
PHP is a server-side technology that creates web pages dynamically. For instance, if there is a product catalog than instead of updating the web pages each time a product is removed or added, the details can be stored in a database and can use PHP to query the database and make the page automatically. So there is no need to build a separate page for each product. Simply build one page and PHP fills in rest of the details itself.
Depending on how PHP is used, its code can be stored in external files or embedded in a web page. Unlike JavaScript or CSS, PHP code always remains on the web server. Visitors to a website never see the code; all they see is the output. It is a great substitute to Microsoft's Active Server Page (ASP) technology.
Other benefits of PHP include uploading files, creating login systems and sending emails. Every news website, online store, social networking site blog uses PHP or a similar server-side technology. PHP is free and offered under an open source license.