PHP (recursive acronym
for "PHP: Hypertext Preprocessor") is a widely-used Open
Source general-purpose scripting language that is
especially suited for Web development and can be embedded
into HTML.
Simple answer, but what does that mean? An
example:
Notice how this is different from a script written in
other languages like Perl or C -- instead of writing a
program with lots of commands to output HTML, you write an
HTML script with some embedded code to do something (in
this case, output some text). The PHP code is enclosed in
special
start and end tags that allow you to jump into and out
of "PHP mode".
What distinguishes PHP from something like client-side
JavaScript is that the code is executed on the server. If
you were to have a script similar to the above on your
server, the client would receive the results of running
that script, with no way of determining what the underlying
code may be. You can even configure your web server to
process all your HTML files with PHP, and then there's
really no way that users can tell what you have up your
sleeve.
The best things in using PHP are that it is extremely
simple for a newcomer, but offers many advanced features
for a professional programmer. Don't be afraid reading the
long list of PHP's features. You can jump in, in a short
time, and start writing simple scripts in a few hours.
Although PHP's development is focused on server-side
scripting, you can do much more with it. Read on, and see
more in the What can PHP
do? section.