PHP Lesson 1: Your First Steps into Server-Side Programming
Welcome to the start of your journey into PHP! If you're looking to build dynamic, interactive websites, PHP is one of the most powerful and widely used languages on the internet.
❓ What is PHP?
PHP stands for Hypertext Preprocessor.
It's a server-side scripting language. This means the code runs on the web server (the computer that hosts your website) before anything is sent to the user's browser.
It's primarily used for web development to generate dynamic content, manage databases, track user sessions, and much more.
It is embedded directly into HTML. You can mix PHP code with your standard HTML markup.
🌐 How PHP Works (Client vs. Server)
To understand PHP, you need to know the difference between the client (the user's web browser) and the server (where your website files live).
Request: A user types your website address into their browser (the Client).
Processing: The Client sends a request to the Server. The Server finds the requested PHP file.
Execution: The Server runs (executes) all the PHP code within that file.
Response: The Server takes the output generated by the PHP (usually HTML, CSS, and JavaScript) and sends it back to the Client.
Display: The Client's browser receives the standard HTML/CSS/JS and displays the final web page.
The important takeaway: The user never sees your raw PHP code—they only see the result (the HTML) it creates.
🛠️ Getting Started: What You Need
To run PHP code on your own computer, you need a local server environment. The easiest way to get this is by installing a WAMP (Windows), MAMP (Mac), or XAMPP (Cross-platform) package.
These packages install everything you need:
A web server (Apache)
PHP
A database (MySQL/MariaDB)
✍️ Your First PHP Program: "Hello, World!"
All PHP files must end with the .php file extension (e.g., index.php).
The PHP Tags
To write PHP, you must enclose your code within special PHP tags:
<?php
// Your PHP code goes here
?>
The echo Statement
The most common way to display output to the user's browser is using the echo statement.
Example 1: Displaying a simple string
Create a file called hello.php and put this inside:
<?php
echo "<h1>Hello, World! This is PHP.</h1>";
?>
When you load this file in your browser via your local server (e.g., http://localhost/hello.php), the browser will receive and display this HTML:
<h1>Hello, World! This is PHP.</h1>
Example 2: Embedding PHP in HTML
You can drop in and out of PHP mode easily.
<!DOCTYPE html>
<html>
<head>
<title>PHP Example</title>
</head>
<body>
<h1>My First Dynamic Page</h1>
<p>The date and time right now is:</p>
<?php
echo "<h2>";
// The date() function outputs the current date and time
echo date("l, F j, Y");
echo "</h2>";
?>
<p>This paragraph is outside the PHP code.</p>
</body>
</html>
🧠 Key Concepts & Rules
Statements End with a Semicolon: Every instruction (statement) in PHP must end with a semicolon (
;). This is a common source of beginner errors!PHPecho "Hello"; // This is a statement echo "World"; // This is another statementCase Sensitivity: PHP is mostly case-sensitive, especially for variable names (we'll cover these next time!).
Comments: You can add notes to your code that the server ignores. Use a double-slash (
//) for single-line comments or/* */for multi-line blocks.PHP// This is a single-line comment /* This is a multi-line comment block. */
🚀 Your First Challenge!
Try modifying the "Hello, World!" example to display:
Your name in an
<h1>tag.Your favorite PHP resource/website in a
<p>tag.
You can do this using a single echo statement or multiple!
I hope this gets you excited about learning PHP. In the next lesson, we will dive into variables and data types—the building blocks of any powerful program!
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