An Introduction to PHP

What is PHP?

PHP is a powerful tool for making dynamic and interactive Web pages.

PHP is a widely used Open Source, general-purpose, Web server-side scripting language. PHP is especially suited for Web development. HTML can be embedded into PHP. PHP is often referred to as a Hypertext Preprocessor and is always used in conjunction with a web server such as Apache.

PHP is actually an interpreter based, Hypertext (HTML) Pre Processor, created to run successfully with a host of Web servers. What PHP does is that it pre-processes the contents of any <filename.php> requested for by a Browser and delivered by the web server. Pre-processing of <filename.php> ensures that only pure HTML is delivered to the requesting Browser, HTML that has been correctly loaded with appropriate, well formatted and styled content.

The fact that PHP runs at the web server has several benefits and a few drawbacks. PHP is actually a simple language, which has great power for manipulating, formatting and styling data and delivering this to a requesting Browser.

PHP is not strongly typecast. PHP really has a very simple way of working with different types of memory variables. Memory variables are not declared to be of a specific type before they can be assigned a value to hold. If a number is assigned to a variable, then it just works. When the variable is later outputted to the browser, it just works. PHP takes care of converting the variable from an integer-type to a string-type, on the fly and automatically. PHP memory variables need not be pre-declared. They are simply created and assigned a value when required for use.

How PHP Works?

PHP sits between a Browser and a Web server. When you type in the URL of a PHP website in a Browser’s address bar and hit the GO key, the Browser sends out a request to the Web server. The Web server then calls the PHP script named in the URL or perhaps index.php which can be visualized as a gateway script. The PHP environment at the Web server executes the script, the output of the PHP script is pure HTML which is then sent back to the requesting Browser as shown in Diagram 1.

Diagram 1

What are PHP benefits?

PHP is a free, open source, Web server side scripting language.

That means you don't have to pay thousands of dollars in licensing fee to acquire PHP. Best of all, it is easy to install. The most striking feature of it is that it is easy to learn.

PHP is used by millions of people and developers around the world. There are thousands of websites on the internet which are written using PHP. One primary example is Yahoo! Bookmarks.

PHP has an ever growing community. There are thousands of websites, forums and community websites dedicated to PHP. Hence, assistance for PHP issues is always available most often for Free or if charged for the charges are always pretty modest.

PHP is a purpose built language for the internet. It is specifically designed to run on web servers to deliver dynamic web pages as quickly as possible, even on extremely high traffic websites.

Security is a huge factor in today's' IT world. PHP has proven itself to be extremely secure and more than sufficient to run high risk sites such as banking or e-commerce applications.

PHP has the huge advantage of being supported by virtually every server in the world. Unlike other languages that require expensive software to be installed on the server, PHP just requires Apache, a lightweight, free server side application that can be installed on any computer in the world. This compatibility and extremely economical running costs makes PHP the number one choice for businesses around the world.