Page 8 - Open Soource Technologies 304.indd

Web Technologies-I

Notes Introduction

Up until recently, scripting on the internet was something which very few people even attempted,
let alone mastered. Recently though, more and more people have been building their own websites
and scripting languages have become more important. Because of this, scripting languages are
becoming easier to learn and PHP is one of the easiest and most powerful yet.
PHP was originally created by Rasmus Lerdorf in 1995. The main implementation of PHP is now
produced by the PHP Group and serves as the de facto standard for PHP as there is no formal
specification. PHP is free software released under the PHP License; it is incompatible with the
GNU General Public License (GPL) due to restrictions on the usage of the term PHP. While
PHP originally stood for “Personal Home Page”, it is now said to stand for “PHP: Hypertext
Preprocessor”, a recursive acronym.
PHP stands for Hypertext Preprocessor and is a server-side language. This means that the script is
run on your web server, not on the user’s browser, so you do not need to worry about compatibility
issues. PHP is relatively new (compared to languages such as Perl (CGI) and Java) but is quickly
becoming one of the most popular scripting languages on the internet.
In this unit we are going to discuss what we can actually do using PHP and the originations of
the PHP as a language. We also discuss the installation of the PHP and some features of PHP.
As mentioned earlier, PHP is a server-side scripting language. This means that, although your
users will not need to install new software, your web host will need to have PHP set-up on their
server. After installing the set-up we can easily run the PHP program.

1.1 What does PHP Do?

PHP can be used in three primary ways:
1.1.1 Server-side Scripting

PHP was originally designed to create dynamic web content, and it is still best suited for that task.
To generate HTML, you need the PHP parser and a web server to send the documents. Lately,
PHP has also become popular for generating XML documents, graphics, Flash animations, PDF
files, and more.

1.1.2 Command-line Scripting
PHP can run scripts from the command line, much like Perl, awk, or the UNIX shell. You might
use the command-line scripts for system administration tasks, such as backup and log parsing.
1.1.3 Graphical Scripting

Using PHP-GTK, you can write full-blown, cross-platform GUI applications in PHP.
PHP runs on all major operating systems, from UNIX variants including Linux, FreeBSD, and
Solaris to such diverse platforms as Windows and Mac OS X. It can be used with all leading web
servers, including Apache, Microsoft IIS, and the Netscape/iPlanet servers.

The language is very flexible. For example, you are not limited to outputting just HTML or other
text files—any document format can be generated. PHP has built-in support for generating PDF
files, GIF, JPG, and PNG images, and Flash movies.
One of PHP’s most significant features is its wide-ranging support for databases. PHP supports
all major databases (including MySQL, PostgreSQL, Oracle, Sybase, and ODBC-compliant
databases), and even many obscure ones. With PHP, creating web pages with dynamic content
from a database is remarkably simple.

2 LOVELY PROFESSIONAL UNIVERSITY