PHP is a preprocessor for hypertext that allows scripting
commands to be embedded in HTML to create dynamic web
pages.
PHP is a server-side scripting technology, which means that
the PHP scripting commands are not visible to the
client.
The capabilities of PHP are similar to those of
other server-side scripting systems, such as CGI scripts. A major
advantage often quoted for PHP is that it provides
effective interfaces to commonly used databases.