$_SERVER['HTTP_HOST'] (your website host): sdhaliya.soisweb.uwm.edu
$_SERVER['PHP_SELF'] (current file path): /infost440/a3/predefined.php
Predefined variables in PHP are built-in variables that are automatically available in every script. Many of them are called superglobals, such as $_SERVER, because they store useful information about the server, the request, and the current script. They help developers debug pages, check file paths, and understand where and how a page is being loaded.