What can PHP do?

Anything. PHP is mainly focused on server-side scripting, so it can do anything any other CGI program can do, such as collect form data, generate dynamic page content, or send and receive cookies. But PHP can do much more.

There are two main areas where PHP scripts are used.

• Server-side scripting. This is the most widely used and main target field for PHP. Three things are needed to make this work: the PHP parser (CGI or server module), a web server, and a web browser. All these can run on a local machine in order to just experiment with PHP programming. See the installation instructions section for more information.
• Command line scripting. A PHP script can be run without any server or browser, only the PHP parser is needed to use it this way. This type of usage is ideal for scripts regularly executed using cron (on Unix or macOS) or Task Scheduler (on Windows). These scripts can also be used for simple text processing tasks. See the section about Command line usage of PHP for more information.

PHP can be used on all major operating systems, including Linux, many Unix variants (including HP-UX, Solaris and OpenBSD), Microsoft Windows, macOS, RISC OS, and probably others. PHP also has support for most of the web servers today. This includes Apache, IIS, and many others. And this includes any web server that can utilize the FastCGI PHP binary, like lighttpd and nginx. PHP works as either a module, or as a CGI processor.

So with PHP, developers have the freedom of choosing an operating system and a web server. Furthermore, they also have the choice of using procedural programming or object-oriented programming (OOP), or a mixture of them both.

PHP is not limited to outputting HTML. PHP's abilities include outputting rich file types, such as images or PDF files, encrypting data, and sending emails. It can also output easily any text, such as JSON or XML. PHP can autogenerate these files, and save them in the file system, instead of printing it out, forming a server-side cache for dynamic content.

One of the strongest and most significant features in PHP is its support for a wide range of databases. Writing a database-enabled web page is incredibly simple using one of the database specific extensions (e.g., for mysql), or using an abstraction layer like PDO, or connect to any database supporting the Open Database Connection standard via the ODBC extension. Other databases may utilize cURL or sockets, like CouchDB.

PHP also has support for talking to other services using protocols such as LDAP, IMAP, SNMP, NNTP, POP3, HTTP, COM (on Windows) and countless others. It can also open raw network sockets and interact using any other protocol. PHP has support for the WDDX complex data exchange between virtually all Web programming languages. Talking about interconnection, PHP has support for instantiation of Java objects and using them transparently as PHP objects.

PHP has useful text processing features, which includes the Perl compatible regular expressions (PCRE), and many extensions and tools to parse and access XML documents. PHP standardizes all of the XML extensions on the solid base of libxml2, and extends the feature set adding SimpleXML, XMLReader and XMLWriter support.

And many other interesting extensions exist, which are categorized both alphabetically and by category. And there are additional PECL extensions that may or may not be documented within the PHP manual itself, like » XDebug.

This page is not enough to list all the features and benefits PHP can offer. Read on in the sections about installing PHP, and see the function reference part for explanation of the extensions mentioned here.