PHP is a server-side scripting language. When a visitor to a WWW page visits a page that is a PHP page, the WWW server gets a PHP processor to examine the page. The PHP processor will produce some HTML which is then shipped by the WWW server to the visitor's computer.

As well as the usual constructs that most languages have, in PHP, you can read from files, write to files and execute system commands; you can send mail; you can interrogate an IMAP server; you can access LDAP servers; you can process XML documents; you can do sophisticated mathematical calculations; you can access most of the popular database servers including Oracle, Sybase, Generic ODBC, MSQL and MySQL; and you can do many other things.

In this document, we look at the language and at some of the above possibilities.