PHP Introduction: Step-by-Step Guide & Best Practices

What Is PHP? (PHP Introduction)

PHP stands for Hypertext Preprocessor.
It is a server-side scripting language mainly used to create dynamic and interactive websites.

In simple terms:

HTML shows content
PHP creates content

PHP runs on the server, processes logic, connects to databases, and sends final HTML to the browser.

PHP Environment

Install a Local Server Environment

To run PHP locally, install one of the following:

Verify PHP Installation

After installation, check if PHP is installed:

  1. Open the command prompt (Windows) or terminal (Mac/Linux).
  2. Type:

This setup is explained in detail here:
PHP Environment

php -v

PHP History and Uses

PHP History

  • Created by Rasmus Lerdorf (1994)

  • Originally built for personal web pages

  • Now powers WordPress, Facebook, Wikipedia

PHP Uses

  • Form handling

  • Database interaction

  • Session management

  • CMS development

  • API creation

 PHP History, and Uses

Why Use PHP?

✔ Easy to learn
✔ Open-source & free
✔ Works with all major databases
✔ Supported by almost all hosting providers
✔ Huge community support

 Why Use PHP?

PHP Basics & Syntax

  1. PHP code is written inside special tags and executed on the server.
<?php
echo "Hello, World!";
?>

Covered Topics:

PHP Output in PHP

PHP displays output using:

  • echo

  • print

PHP Echo, Print & Output Functions

PHP Comments

Comments are used to explain code and improve readability.

 
 
// Single-line comment
/* Multi-line comment */

PHP Variables and Constants

Variables

Used to store data.

$name = "John";

Constants

Values that do not change.

define("SITE", "MyWebsite");

PHP Variable

PHP Data Types

PHP supports multiple data types:

  • String

  • Integer

  • Float

  • Boolean

  • Array

  • Object

  • NULL

PHP Data Types

PHP Type Casting

Type casting converts one data type to another.

$num = (int)"10";

PHP Type Casting

PHP Operators

Operators perform operations on variables.

Operator Topics:

PHP Control Structures

Control structures control the flow of execution.

Topics Included:

PHP Loops

Loops execute code repeatedly.

PHP Functions

Functions are reusable blocks of code.

Function Topics:

PHP Arrays

Arrays store multiple values in one variable.

Array Topics:

PHP String Handling

Used to manipulate text.

PHP Superglobals

Superglobals are built-in variables accessible anywhere.

Covered Superglobals:

PHP File Handling

PHP can work with files on the server.

File Topics:

PHP Database (MySQL)

PHP is widely used with MySQL databases.

MySQL Topics: