Introduction to PHP

PHP is one of the most popular programming languages of the Internet. Even people who are not programmers or web developers have heard of PHP. PHP has come to enjoy widespread use among web developers and is probably the most common language used for open source web applications today. PHP is freely available, included with nearly every web server, flexible, and very powerful. The language's name is actually a recursive acronym, popular in UNIX and Linux, and stands for PHP: Hypertext Preprocessor.

What is PHP

PHP is a server-side scripting language used for programming websites. The web server processes the PHP script and then sends the results to the requesting web browser like a normal HTML file. PHP scripts can be included within an HTML file or can be a standalone file. PHP scripts can be used to provide a small amount of dynamic content to a website or can be used to create complex web applications. PHP is the open source alternative to commercial web application solutions like Microsoft's ASP or Adobe's ColdFusion.

Why Use PHP

There are many excellent reasons to use PHP. A few of the most common are:

Open Source - One of the top reasons many people use PHP is because it is open source software. Open source software is freely available and does not involve expensive licensing or purchase costs like many commercial competitors.

Resources - Open source projects like PHP usually have nearly limitless documentation, examples, and source code freely available on the Internet. Many books and magazines also have information on using PHP as well.

Freely Available - Nearly every web server has PHP installed on it already. Even many free and low-cost shared hosting providers include PHP. Since PHP is freely available and runs on Apache and Microsoft IIS (as well as others) you can easily install PHP on your server if it is not included already. This universal availability means you are not locked in with an expensive, proprietary software solution.

Powerful - PHP is powerful enough to do what you need - almost without exception. The language is extremely powerful and becomes more powerful with each release.

Flexible - PHP is extremely flexible and can be used to create a simple, dynamic website or a powerful, complete web application.

Database Support - PHP provides support for multiple databases, including the immensely popular, open source MySQL. MySQL is probably the most common database paired with PHP since MySQL is also open source, freely available, powerful, flexible, and available on nearly every web server.

Cross-Platform Compatibility - PHP's cross-platform compatibility means you can develop your website or web application on one operating system and deploy it on another. The most common example of this would be developing in PHP on your Microsoft Windows PC and then uploading the site or application to your Linux web server.

How Do I Use PHP

PHP files can be written in any text editor. Using PHP does not lock you into a proprietary development environment. Most people prefer to use a text editor with syntax highlighting, however. Syntax highlighting does make the coding much easier. PHP files must be saved with a .php extension so that the server knows to parse the file before sending the results back to the requesting web browser.

PHP needs to be installed on your web server in order to use PHP in your site. Most web servers will already have PHP installed. PHP can be downloaded and installed on your server if it is not installed already. However, most people may find it easier to change hosting providers rather than to install PHP themselves. Finding a hosting provider that includes PHP will not be difficult.

PHP files can be uploaded by FTP or created directly on the server using SSH. Many people prefer to create the files on their computer and then upload them to the server by FTP.

Since PHP is a server -side scripting language all PHP files are parsed by the browser before the results are sent to the browser. This creates exciting opportunities for creating dynamic and database driven websites. Since the PHP scripts are processed before the results are sent you can use your PHP scripts to query a database, execute conditional statements, or serve specific content based on who is using the site.

Review

• PHP is a popular, open source, server-side scripting language
• PHP is flexible, powerful, and widely available
• PHP scripts are executed on the server before the results are sent to the browser thus creating exciting opportunities for dynamic and database-powered websites