? PHP Introduction

? Quick Overview

PHP stands for Hypertext Preprocessor. It is a widely-used, open-source scripting language especially suited for web development and can be embedded directly into HTML.

PHP is a server-side language, meaning the code runs on the server and sends only the final output (HTML) to the browser.

? Key Concepts

Server-side scripting language
Open-source and cross-platform
Used to create dynamic web pages
Works seamlessly with databases

⚙️ Syntax & Theory

PHP code is written inside <?php ... ?> tags. Each statement ends with a semicolon.

? View Code Example

// Basic PHP syntax example
<?php
echo "Hello, World!";
?>

⚡ Interactive PHP Simulator

Change the code in the "Server" side to see how it renders on the "Client" side.

?️ Server Side (PHP)

? Client Side (Browser)

Server Processing...

Click process to see output...

? Embedding PHP in HTML

PHP can be embedded directly inside HTML files to generate dynamic content.

? View Code Example

// PHP embedded inside HTML
<!DOCTYPE html>
<html>
<body>
<h1>Welcome</h1>
<p>
<?php
echo "Hello, World!";
?>
</p>
</body>
</html>

? Live Output / Explanation

Output

The browser receives plain HTML such as Hello, World! after the PHP code executes on the server.

?️ Interactive Understanding

Think of PHP as a hidden engine. Users never see the PHP code—only the result it produces.

? Use Cases

User login and authentication systems
Form handling and validation
Database-driven websites
Content Management Systems (WordPress)

✅ Tips & Best Practices

Use XAMPP or WAMP for local PHP development
Always comment your code for clarity
Keep PHP logic separate from HTML when possible

? Try It Yourself

Create a file named index.php and print a greeting
Display today’s date using PHP
Embed PHP inside an HTML paragraph