Introduction To PHP | PHP Notes

In this article, we’ll introduce you to PHP, one of the most popular server-side scripting languages used for web development. You’ll learn what PHP is, its history, and how it works in the background to generate dynamic content. By the end of this post, you’ll have a solid understanding of why PHP is a powerful tool for creating web applications and how it integrates with HTML, CSS, and JavaScript. This is the first step towards mastering PHP and building dynamic websites. Let’s dive in!

What is PHP ?

  • PHP is an open-source general purpose scripting language, widely used for website development. It is developed by Rasmus Lerdorf. PHP stands for a recursive acronym PHP: Hypertext Preprocessor.
  • It is a server-side scripting language primarily designed for web development.
  • It is embedded in HTML and executed on the server, meaning that PHP scripts generate dynamic content that is sent to the user’s browser.
  • PHP is open-source, free to use, and highly flexible, which is why it’s used by millions of developers worldwide.

Key Characteristics :

  • Server-Side Scripting: PHP runs on the server, not the client.
  • Open-Source: Free to download and use.
  • Cross-Platform: Works on various platforms (Windows, Linux, mac, etc)

Why Learn PHP?

PHP one of the most preferred languages for creating interactive websites and web applications. PHP scripts can be easily embedded into HTML. With PHP, you can build

  • Web Pages and Web-Based Applications
  • Content Management Systems, and
  • Ecommerce Applications etc.

A number of PHP based web frameworks have been developed to speed-up the web application development. The examples are WordPress, Laravel, Symfony etc.

History of PHP

PHP was originally created by Rasmus Lerdorf in 1994. Initially, it was a set of Common Gateway Interface (CGI) binaries written in C, which Rasmus used to track visits to his online resume. Since then, PHP has grown into a robust programming language with a large community of developers and significant updates, with major versions including PHP 3, PHP 5, and the latest versions like PHP 7 and PHP 8.

Key milestones:

  • 1994: Rasmus Lerdorf creates PHP as “Personal Home Page Tools.”
  • 1997: PHP3 is released, which marks its official public use.
  • 2004: PHP5 introduces object-oriented programming features.
  • 2015: PHP7 brings significant performance improvements.
  • 2020: PHP8 is released with JIT compilation.
  • 2023: PHP8.2 is released.

Advantages of PHP

PHP is widely preferred for web development due to its rich set of features. Here are some of the key advantages:

  • Simplicity: PHP’s syntax is simple and easy to learn.
  • Embedded in HTML: PHP code can be directly embedded within HTML code, making it highly convenient for developers.
  • Cross-Platform Compatibility: PHP scripts can be run on different operating systems like Windows, Linux, and macOS.
  • Database Support: PHP supports a wide variety of databases such as MySQL, PostgreSQL, Oracle, and more.
  • Large Community: PHP has a vast community, which means you can find solutions and libraries for almost any task.
  • Fast and Efficient: PHP executes on the server-side, offering faster page loads and efficient content generation.
  • Similar Syntax: PHP has a familiar C-like syntax.

How PHP Works

PHP works on the server-side, meaning that PHP code is executed on the server, and the resulting HTML is sent to the client’s browser. The user never sees the PHP code itself. Here’s how it works:

  1. The user requests a PHP page: A user accesses a webpage containing PHP code.
  2. Server processes PHP: The web server processes the PHP code and executes any commands written in the script.
  3. HTML is sent to the browser: Once the server executes the PHP code, it generates HTML that is sent back to the user’s browser.
  4. User views the webpage: The user sees the output, which may be static HTML or dynamic content generated by PHP.

Hello World Program in PHP

<?php
echo "Hello, World!";
?>
PHP

In this PHP code, the server processes the PHP echo statement, and the browser receives the text “Hello, World!” as plain HTML.

PHP with HTML, CSS, and JavaScript

One of the great features of PHP is its ability to integrate seamlessly with other web technologies like HTML, CSS, and JavaScript. Here’s a simple example of how PHP is embedded into HTML:

<!DOCTYPE html>
<html>
<head>
    <title>PHP Example</title>
</head>
<body>
    <h1><?php echo "Hello from PHP!"; ?></h1>
</body>
</html>
PHP

In this example, PHP is used to dynamically generate the content inside the <h1> tag. PHP can also be used to manipulate data, interact with databases, and control other backend logic while HTML and CSS manage the front-end layout and design.

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