PHP Introduction

What is PHP?

• PHP (PHP: Hypertext Preprocessor) is a popular server-side scripting language designed for web development.
• It can be embedded within HTML and runs on the server to generate dynamic web pages before sending them to users’ browsers.

<?php
echo "Hello, World!"; // This runs on the server
?>
<h1>Welcome to my website</h1> <!-- This is HTML -->

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History & Evolution

• 1994: Created by Rasmus Lerdorf as “Personal Home Page”
• 1997: PHP 3 released, renamed to “PHP: Hypertext Preprocessor”
• 2000: PHP 4 with Zend Engine introduced object-oriented features
• 2004: PHP 5 enhanced OOP capabilities significantly
• 2015: PHP 7 brought major performance improvements (2x faster)
• 2020: PHP 8 added JIT compilation and new syntax features

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Key Features

Server-Side Processing

• Code executes on the server, not in the browser
• Users only see the HTML output, never the PHP source code
• Perfect for handling databases, user authentication, and dynamic content

Easy to Learn

Example of PHP variables and loops:

<?php
// Variables are simple - just add $
$age = 20;
$name = "Alice";
$isStudent = true;

// Mix PHP with HTML easily
echo "<h1>Hi $name, you are $age years old!</h1>";

// Arrays and loops are straightforward
$subjects = ["Math", "Science", "History"];
foreach ($subjects as $subject) {
    echo "<li>$subject</li>";
}
?>

Database Integration

• Built-in support for MySQL, PostgreSQL, SQLite, and more
• Simple database operations with PDO or mysqli

Cross-Platform

• Runs on Windows, Linux, macOS, and most web servers
• Works with Apache, Nginx, IIS, and others

Open Source & Free

• Completely free to use for any purpose
• Large community and extensive documentation

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Why Choose PHP?

Advantage	Description
Rapid Development	Quick to write and deploy web applications
Huge Community	Millions of developers, extensive resources
Frameworks Available	Laravel, Symfony, and Slim microframework for faster development
Web-Focused	Built specifically for web development
Flexible	Works with HTML, CSS, JavaScript seamlessly

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What Can You Build?

• Websites: Personal blogs, business sites, portfolios
• E-commerce: Online stores with shopping carts and payments
• Content Management: WordPress, Drupal are built with PHP
• Web Applications: Social networks, forums, booking systems
• APIs: RESTful services for mobile apps and integrations

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PHP vs Other Languages

PHP Strengths:

• Designed for web development
• Easy hosting and deployment
• Extensive web-specific functions
• Large ecosystem of frameworks and tools

When to Choose PHP:

• Building web applications or websites
• Need rapid development and deployment
• Working with databases and dynamic content
• Want a gentle learning curve for web development