Introduction

PHP, which stands for "PHP: Hypertext Preprocessor," is a widely-used open-source scripting language that is especially suited for web development and can be embedded into HTML. PHP scripts are executed on the server, and the result is returned to the browser as plain HTML.

Key Features of PHP

Server-Side Scripting: PHP is executed on the server, which means the code runs on the web server and the result is sent to the client's web browser.
Open Source: PHP is free to use and distribute, with a large community of developers contributing to its development.
Cross-Platform: PHP runs on various platforms, including Windows, Linux, Unix, and macOS.
Embedded in HTML: PHP can be embedded directly into HTML code, making it easy to add dynamic content to web pages.
Database Integration: PHP supports a wide range of databases, including MySQL, PostgreSQL, SQLite, and more.
Extensive Library Support: PHP has a rich set of built-in functions and libraries, which makes development faster and easier.

How PHP Works

When a user requests a PHP page, the following steps occur:

Request: The user requests a PHP page by entering a URL in the browser.
Server Processing: The web server processes the PHP code on the server side.
Output: The server sends the generated HTML output to the user's browser.

Here is a simple diagram to illustrate the process:

Step	Description
1. Request	User requests a PHP page by entering a URL in the browser.
2. Server	The web server processes the PHP code on the server side.
3. Output	The server sends the generated HTML output to the user's browser.

Practical Example

Let's look at a simple example of a PHP script embedded in an HTML file:

<!DOCTYPE html>
<html>
<head>
    <title>My First PHP Page</title>
</head>
<body>
    <h1>Welcome to My First PHP Page</h1>
    <?php
        echo "Hello, World!";
    ?>
</body>
</html>

Explanation

HTML Structure: The HTML structure includes the <!DOCTYPE html>, <html>, <head>, and <body> tags.
PHP Code: The PHP code is embedded within <?php ... ?> tags.
echo Statement: The echo statement outputs the string "Hello, World!" to the web page.

Exercise

Task

Create a simple PHP script that displays the current date and time.

Solution

<!DOCTYPE html>
<html>
<head>
    <title>Current Date and Time</title>
</head>
<body>
    <h1>Current Date and Time</h1>
    <?php
        echo "The current date and time is: " . date("Y-m-d H:i:s");
    ?>
</body>
</html>

Explanation

date Function: The date function formats a local date and time, and the format "Y-m-d H:i:s" represents the year, month, day, hour, minute, and second.

Common Mistakes

Forgetting the PHP Tags: Ensure that PHP code is enclosed within <?php ... ?> tags.
Syntax Errors: Pay attention to syntax, such as missing semicolons (;) at the end of statements.
Case Sensitivity: PHP is case-sensitive for variable names but not for function names.

Conclusion

In this lesson, you learned what PHP is, its key features, and how it works. You also saw a practical example of embedding PHP in HTML and created a simple script to display the current date and time. Understanding these basics is crucial as you move forward in learning PHP and developing dynamic web applications.

What is PHP?

Introduction

Key Features of PHP

How PHP Works

Practical Example

Explanation

Exercise

Task

Solution

Explanation

Common Mistakes

Conclusion

PHP Programming Course

Module 1: Introduction to PHP

Module 2: Control Structures

Module 3: Functions

Module 4: Arrays

Module 5: Working with Forms

Module 6: Working with Files

Module 7: Object-Oriented Programming (OOP)

Module 8: Working with Databases

Module 9: Advanced PHP Techniques

Module 10: PHP Frameworks and Best Practices

Module 11: Project: Building a Web Application