What are the differences between the document root in the file system and the root directory of the server when generating paths in PHP?

When generating paths in PHP, it's important to understand the differences between the document root in the file system and the root directory of the server. The document root in the file system is the directory where the website files are stored, while the root directory of the server is the top-level directory on the server. To generate correct paths, you need to use the appropriate variables provided by PHP ($_SERVER['DOCUMENT_ROOT'] for the document root and $_SERVER['DOCUMENT_ROOT'] for the server root) to construct paths dynamically.

// Constructing a path using the document root
$filePath = $_SERVER['DOCUMENT_ROOT'] . '/path/to/file.php';

// Constructing a path using the server root
$serverPath = $_SERVER['DOCUMENT_ROOT'] . '/path/to/server/directory/';