Introduction to PHP

PHP is a server-side scripting language. That is used to develop Static websites or Dynamic websites or Web applications. PHP stands for Hypertext Pre-processor, that earlier stood for Personal Home Pages.

• PHP scripts can only be interpreted on a server that has PHP installed.
• The client computers accessing the PHP scripts require a web browser only.
• A PHP file contains PHP tags and ends with the extension ".php".

What is Scripting Language?

• A script is a set of programming instructions that is interpreted at runtime.
• A scripting language is a language that interprets scripts at runtime. Scripts are usually embedded into other software environments.
• The purpose of the scripts is usually to enhance the performance or perform routine tasks for an application.
• Server-side scripts are interpreted on the server while client side scripts are interpreted by the client application.
• PHP is a server-side script that is interpreted on the server while JavaScript is an example of a client-side script that is interpreted by the client browser. Both PHP and JavaScript can be embedded into HTML pages.

Programming Language Vs Scripting Language

Programming language	Scripting language
Has all the features needed to develop complete applications.	Mostly used for routine tasks
The code has to be compiled before it can be executed	The code is usually executed without compiling
Does not need to be embedded into other languages	Is usually embedded into other software environments.

What does PHP stand for?

PHP means - Personal Home Page, but it now stands for the recursive backronym PHP: Hypertext Preprocessor.

PHP code may be embedded into HTML code, or it can be used in combination with various web template systems, web content management system and web frameworks.

Php Syntax

A PHP file can also contain tags such as HTML and client side scripts such as JavaScript.

• HTML is an added advantage when learning PHP Language. You can even learn PHP without knowing HTML but it’s recommended you at least know the basics of HTML.
• Database management systems DBMS for database powered applications.
• For more advanced topics such as interactive applications and web services, you will need JavaScript and XML.

The flowchart diagram shown below illustrates the basic architecture of a PHP web application and how the server handles the requests.

Why use PHP?

You have obviously heard of a number of programming languages out there; you may be wondering why we would want to use PHP as our poison for the web programming. Below are some of the compelling reasons.

• PHP is open source and free.
• Short learning curve compared to other languages such as JSP, ASP etc.
• Large community document
• Most web hosting servers support PHP by default unlike other languages such as ASP that need IIS. This makes PHP a cost effective choice.
• PHP is regular updated to keep abreast with the latest technology trends.
• Other benefit that you get with PHP is that it’s a server side scripting language; this means you only need to install it on the server and client computers requesting for resources from the server do not need to have PHP installed; only a web browser would be enough.
• PHP has in built support for working hand in hand with MySQL; this doesn’t mean you can’t use PHP with other database management systems. You can still use PHP with
• Postgres
• Oracle
• MS SQL Server
• ODBC etc.
• PHP is cross platform; this means you can deploy your application on a number of different operating systems such as windows, Linux, Mac OS etc.

What is PHP used for & Market share

In terms of market share, there are over 20 million websites and application on the internet developed using PHP scripting language.

This may be attributed to the points raised above;

The diagram below shows some of the popular sites that use PHP

PHP File Extensions

File extension and Tags In order for the server to identify our PHP files and scripts, we must save the file with the “.php” extension. Older PHP file extensions include

• .phtml
• .php3
• .php4
• .php5
• .phps

The PHP tags themselves are not case-sensitive, but it is strongly recommended that we use lower case letter. The code below illustrates the above point.

<?php … ?>

We will be referring to the PHP lines of code as statements. PHP statements end with a semi colon (;). If you only have one statement, you can omit the semi colon. If you have more than one statement, then you must end each line with a semi colon. For the sake of consistency, it is recommended that you always end your statement(s) with a semi colon.  PHP scripts are executed on the server. The output is returned in form of HTML.

How to run PHP?

Manual installation of a Web server and PHP requires in-depth configuration knowledge but the XAMPP suite of Web development tools, created by Apache Friends, makes it easy to run PHP. Installing XAMPP on Windows only requires running an installer package without the need to upload everything to an online Web server. This PHP Tutorial gives you an idea of XAMPP and how it is used for executing the PHP programs.

What is XAMPP?

It is a free and open-source cross-platform webserver solution stack package developed by Apache Friends that consists of the Apache HTTP Server, MariaDB & MySQL database, and interpreters for scripts are written in the PHP and Perl programming languages. XAMPP stands for Cross-Platform (X), Apache (A), MariaDB & MySQL (M), PHP (P) and Perl (P). It is a simple, lightweight Apache distribution that makes it extremely easy for developers to create a local web server for testing and deployment purposes.

PHP using WAMP Server

If you’re working on a project for the production environment and have a PC running the Windows OS then you should opt for WAMP server because it was built with security in mind. You can use this method to run PHP scripts you may have obtained from somewhere and need to run with little or no knowledge of PHP. You can execute your scripts through a web server where the output is a web browser.

Let’s have a look at the steps involved in using WAMP Server:

1. Install the Server Software
2. Set up the Server
3. Save PHP Scripts
4. Run PHP Scripts
5. Troubleshoot

Now let’s move ahead with our PHP Tutorial and find out the suitable IDE for PHP.

PHP IDE

In order to remain competitive and productive, writing good code in minimum time is an essential skill that every software developer must possess. As the number and style of writing code increases and new programming languages emerge frequently, it is important that the software developers must opt for the right IDE to achieve the objectives.

An Integrated Development Environment or IDE is a self-contained package that allow you to write, compile, execute and debug code in the same place. So let’s have a look at some of the best IDE’s for PHP:

• PHPStorm
• Netbeans
• Aptana Studio
• Eclipse
• Visual Code Editor
• ZendStudio

PHP Hello world

The program shown below is a basic PHP application that outputs the words “Hello World!” When viewed in a web browser.

<?php

echo "Hello world";

?>

Output:

Hello world