PHP Lecture One: What is PHP?

Welcome to the first lecture in our PHP series! In this post, we’ll explore the fundamentals of PHP, a popular programming language that powers much of the web today.

What is PHP?

PHP (Hypertext Preprocessor) is a widely-used open-source scripting language designed for web development. Initially created by Rasmus Lerdorf in 1994, PHP has evolved into one of the most powerful and versatile languages for server-side programming. It's especially known for its ability to integrate seamlessly with HTML, allowing developers to create dynamic web pages.

How Does PHP Work?

PHP is a server-side scripting language, meaning the code is executed on the server rather than the user's browser. When a user requests a web page, the server processes the PHP code and generates HTML, which is then sent to the user's browser.

Here’s a simple workflow of how PHP works:

1. Request: The user requests a page (for example, index.php) from the server.
2. Server Processing: The web server processes the PHP code embedded in the page.
3. HTML Output: The server sends the generated HTML back to the user's browser.
4. User View: The browser displays the content as a regular webpage.

This process happens very quickly, allowing users to interact with websites in real time.

Why Choose PHP?

1. Open Source: PHP is free to use and has an extensive online community that contributes to its continuous improvement.

2. Platform Independence: PHP works across different operating systems such as Windows, Linux, and macOS. This allows developers to build applications that can run on various platforms.

3. Integration with Databases: PHP easily integrates with databases, particularly MySQL, allowing developers to create dynamic, data-driven websites.

4. Server-Side Scripting: Being a server-side language, PHP ensures better performance and security. It runs on the server, and users cannot view the code or make changes to it from the client side.

5. Rich Ecosystem: PHP is not just a language, but a full ecosystem with frameworks like Laravel, Symfony, and CodeIgniter that make web development faster and more structured.

Basic Syntax of PHP

PHP code is embedded into HTML using the <?php ... ?> tags. Here’s a simple example of PHP embedded in HTML:

In this example:

• The <?php tag marks the start of PHP code.
• The echo statement outputs the text "Hello, World!" to the browser.

PHP in the Real World

PHP is used by many popular websites and platforms. For example:

• WordPress: The most widely used content management system (CMS) in the world, powering millions of websites, is built using PHP.
• Facebook: Originally built on PHP, Facebook’s core is still maintained using PHP, albeit with several custom optimizations.
• Wikipedia: The world’s largest online encyclopedia runs on PHP.

Many eCommerce sites, blogs, forums, and web applications also use PHP due to its flexibility, scalability, and wide support.

Conclusion

PHP is an essential tool in the world of web development. Its versatility, ease of use, and power make it a great choice for building dynamic websites and applications. Whether you're a beginner just starting with PHP or a seasoned developer, understanding PHP is crucial for developing modern web applications.

In the next lecture, we’ll dive deeper into PHP's syntax, data types, and variables. Stay tuned!