HTTP Superglobals ($_GET, $_POST)

🐘 PHP Lesson 10 Intermediate

Superglobals are built-in variables that are globally accessible in all scopes. They handle HTTP client requests and server parameters.

1 Query Strings ($_GET) vs. Request Payloads ($_POST)

Common PHP superglobals include:

$_GET: Collects parameters sent via the URL query string (e.g. `?id=5`). Visible in the browser address bar.
$_POST: Collects parameters sent via HTTP POST requests (e.g. submitted HTML forms). Form data is hidden inside the request payload, making it secure for passwords.
$_SERVER: Stores server configuration parameters and headers, such as user agents and request methods.

2 Superglobals Code

Let's look at an example illustrating superglobal properties:

PHP — Superglobals ▶ Run Code

<?php
// Simulating incoming HTTP context values inside arrays
$_GET['id'] = "105";
$_POST['username'] = "Balaji";

echo "GET parameter ID: " . $_GET['id'] . "\n";
echo "POST parameter Username: " . $_POST['username'] . "\n";
echo "Request Script Name: " . $_SERVER['SCRIPT_NAME'] . "\n";
?>

3 Code Challenge

Challenge: Write a script that checks if `$_SERVER['REQUEST_METHOD']` is equal to "POST". If it is, output the username parameter from `$_POST`; otherwise, print a warning message.