$_SERVER is automatically populated by PHP with information about the server
environment and the current HTTP request.
| Key | Value | What It Means |
|---|---|---|
$_SERVER['PHP_SELF'] | /infost440/a3/predefined.php | The filename of the currently executing script |
$_SERVER['SERVER_NAME'] | brough27.soisweb.uwm.edu | The hostname of the server |
$_SERVER['REQUEST_METHOD'] | GET | The HTTP method used (GET or POST) |
$_SERVER['SERVER_PORT'] | 443 | The port the server is listening on |
$_SERVER['SERVER_SOFTWARE'] | Apache | The server software and version |
These keys reveal information about the visitor making the request.
echo $_SERVER['REMOTE_ADDR']; // Visitor IP address
echo $_SERVER['HTTP_USER_AGENT']; // Visitor browser and OS
REMOTE_ADDR: 216.73.216.9 — The IP address of the visitor.
HTTP_USER_AGENT: Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com) — The visitor's browser and operating system.
PHP's predefined variables, also called superglobals, are built-in
variables that PHP automatically creates and populates at the start of every request. They are
available in every scope of every script including inside functions and classes without needing
any special declaration. You do not create or initialize them — PHP handles that automatically
based on the server environment and incoming HTTP data. Examples include $_SERVER
(server and request info), $_GET (URL query parameters), $_POST
(form submission data), $_SESSION (session data), and $_COOKIE
(browser cookies). These superglobals are essential for building dynamic web applications
because they give PHP direct access to who is visiting and how they sent data.
INFOST 440 — Activity 3 — Nyla Broughton