PHP Basic Structure

PHP Definition  
According to official documents of PHP, PHP stands for PHP Hypertext Preprocessor.
It is a form of language scripts that are placed in the server and processed on the server.  
The results are sent to the client, the user using the browser.  
PHP is a server-side scripting language that integrates with HTML
to create dynamic web pages. The purpose of the server-side scripting
is the syntax and the commands that we give will be entirely run on the
server but is included in regular HTMLdocuments. PHP is free to use.
You do not have to pay anything for using this software, aka free.
You can download it via the site http://www.php.net. PHP is available 
in binary code form as well as complete source code.

PHP Style 
 PHP gives us flexibility when writing a program, 
with records still refer to the conditions set. Please note that by the time 
PHP parse the file, the tag will be read to meet the special tags which tell
for menerjemahkanya as PHP code. If the tag is found, then parser to 
execute the program code until the end on the closing tag. This also
applies to the PHP code is embedded in HTML documents, which 
the parser will find the tags to be found. The rest are outside the tags will
be deemed not is the PHP code, so the parser is also no need to process it. 
 There are four ways to write a tag that identifies the PHP program.