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This beginner module explains how websites work and introduces PHP as a server-side language. It covers the request flow from browser to server, the difference between client-side and server-side code, installing XAMPP or MAMP, and writing basic PHP syntax including output and comments.
- A website is hosted on a server; the browser sends an HTTP request, DNS finds the IP, the server responds with HTML/CSS/JS, and the browser renders it.
- Client-side code (HTML, CSS, JavaScript) runs in the browser, while server-side code (PHP, Python, Node.js) runs on the server.
- XAMPP includes Apache, MySQL, PHP, and phpMyAdmin; start Apache and MySQL, then place PHP files in C:/xampp/htdocs/ and open them via http://localhost/.
- PHP code goes inside <?php ... ?> tags, statements end with a semicolon, and function names are case-insensitive.
- Use echo or print to output text, and use //, #, or /* ... */ for comments.
📘 Module 1: Introduction to Web & PHP
✅ 1. What is a Website & How It Works
- A website is a collection of related web pages hosted on a server.
- Users access websites using browsers by typing a URL like
https://www.example.com. - The browser sends an HTTP request to the server, which responds with HTML/CSS/JS files.
Basic flow of how a website works:
1. User enters a URL in browser → www.example.com
2. DNS translates domain to IP → 192.168.1.1
3. Request sent to web server (Apache/Nginx)
4. Server processes request and sends back response (HTML/CSS/JS)
5. Browser renders the content on screen
✅ 2. Client vs Server-side Technologies
- Client-side: Code that runs in the browser (HTML, CSS, JavaScript).
- Server-side: Code that runs on the server (PHP, Python, Node.js, etc).
Client vs Server Example:
Client: Sends form data (like login info) using HTML/JS
Server: PHP receives form data, checks database, returns result
✅ 3. Installing XAMPP / WAMP / MAMP
- Install XAMPP (Windows/Linux) or MAMP (Mac).
- XAMPP includes Apache, MySQL, PHP, and phpMyAdmin.
- Start Apache and MySQL from the XAMPP Control Panel.
- Your localhost URL:
http://localhost/
Directory for PHP files: C:/xampp/htdocs/
✅ 4. Creating First PHP File (hello.php)
Inside your htdocs folder, create a new file called hello.php with this code:
<?php
echo "Hello, world!";
?>
Then open your browser and go to:
http://localhost/hello.php✅ 5. PHP Syntax and Tags
- PHP code is written inside
<?php ... ?>tags. - Each statement ends with a semicolon
;. - PHP is case-insensitive for functions (e.g.,
echo=ECHO).
<?php
$name = "Umar";
echo "Welcome, " . $name;
?>
✅ 6. Echo and Print
echoandprintare both used to output text.echois slightly faster and can output multiple values.
<?php
echo "Hello ";
echo "World!<br>";
print "This is printed using print!";
?>
✅ 7. PHP Comments
- Single-line comments:
//or# - Multi-line comments:
/* ... */
<?php
// This is a single-line comment
# This is also a single-line comment
/* This is a
multi-line comment */
echo "Comments are ignored by PHP!";
?>