URL Parameters Demo

How URL Parameters Work

URL parameters (also called query strings) pass data directly in the URL after a ? character:

https://example.com/search?query=hello&page=2

The format is key=value pairs separated by &.

Try It: Sign Up Form

This form uses method="GET", which appends the data to the URL. Watch the address bar after you submit!

First Name: Last Name: Email: T-Shirt Size: Small Medium Large Extra Large Submit (GET)

What You'll See

After submitting, your URL will look something like:

result.php?firstName=Alice&lastName=Smith&email=alice%40example.com&size=M

Notice that @ becomes %40 - this is URL encoding for special characters.

Good Uses for URL Parameters

• Search queries: /search?q=web+development
• Pagination: /products?page=3
• Filters: /catalog?category=books&sort=price
• Tracking: /landing?utm_source=newsletter
• Configuration: /report?format=pdf&year=2024

Accessing URL Parameters in PHP

<?php
// URL: result.php?firstName=Alice&lastName=Smith

// Access via $_GET superglobal array
$firstName = $_GET['firstName'] ?? '';  // 'Alice'
$lastName = $_GET['lastName'] ?? '';    // 'Smith'

// Always sanitize before outputting!
echo htmlspecialchars($firstName);
?>

---

Back to State Management | Next: Cookies Demo