PHP Introduction

🔹 What is PHP?

PHP (Hypertext Preprocessor) is a popular server-side scripting language designed for web development. It allows developers to create dynamic and interactive web applications. Unlike HTML, which is static, PHP enables web pages to change based on user input, database queries, and other conditions.

🔹 Why Use PHP?

✔ Open-source & Free – Available for everyone to use and modify.
✔ Server-side Execution – Code runs on the server before sending output to the browser.
✔ Cross-Platform – Works on Windows, Linux, and macOS.
✔ Database Integration – Supports MySQL, PostgreSQL, SQLite, and more.
✔ Fast & Secure – Optimized for web applications with built-in security features.
✔ Easy to Learn – Similar to C, Java, and Perl, making it beginner-friendly.

🔹 How PHP Works?

When a user requests a PHP page, the following happens:
1️⃣ The browser sends a request to the server.
2️⃣ The server processes the PHP code.
3️⃣ The output (usually HTML) is sent back to the browser.

PHP code is executed on the server, meaning the user only sees the final output, not the PHP code itself.

🔹 Where is PHP Used?

PHP is widely used in web development for:
✅ Creating dynamic web pages.
✅ Handling forms (login, registration, contact forms, etc.).
✅ Managing databases (CRUD operations – Create, Read, Update, Delete).
✅ User authentication (login & signup systems).
✅ Developing CMS (Content Management Systems) like WordPress, Joomla, and Drupal.
✅ Processing files, cookies, and sessions.

🔹 PHP Syntax and Structure

PHP scripts start with <?php and end with ?>.
PHP is case-sensitive for variables but not for keywords and function names.
PHP statements end with a semicolon ;.

Basic PHP Code Example

<?php
echo "Hello, World!";  // Outputs text to the browser
?>

🔹 Explanation:

echo is used to display output.
The text "Hello, World!" is printed in the browser.

Using PHP Inside HTML

<!DOCTYPE html>
<html>
<head>
    <title>PHP Example</title>
</head>
<body>
    <h1>Welcome to My Website</h1>
    <p>Today’s date is: <?php echo date("Y-m-d"); ?></p>
</body>
</html>

🔹 Explanation:

PHP can be embedded directly within an HTML file.
The date("Y-m-d") function prints the current date.

🔹 PHP Variables and Data Types

PHP variables store values and start with $.

Example: Declaring Variables

<?php
$name = "John"; // String
$age = 25;      // Integer
$price = 99.99; // Float
$is_admin = true; // Boolean

echo "Name: " . $name;
?>

🔹 Conclusion

PHP is a powerful, flexible, and widely-used server-side language for creating dynamic and interactive web applications. It is easy to learn, supports databases, and is used by major platforms like WordPress, Facebook, and Wikipedia. 🚀