What is the recommended method for determining the previous URL in a PHP website?

To determine the previous URL in a PHP website, you can use the $_SERVER['HTTP_REFERER'] variable. This variable contains the URL of the previous page that linked to the current page. By checking this variable, you can determine where the user came from before landing on the current page.

$previous_url = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : 'No previous URL found';
echo $previous_url;