The default document for my website is index.php. If people visit my website www.MySite.com/ the referrer is empty when I look at it in my index.php file. If they visit www.MySite.com/index.php, the referrer is visible and I capture it with $_SERVER['HTTP_REFERER']. I know not every browser will forward the referrer.
How can I capture the referrer from the root directory if it exists?
If the user entered the URL manually, or clicked a link from a favourite list in his browser, there is no referer. He literally came from nowhere :)