Removing query string in PHP (sometimes based on referrer)

Question

Hi on Facebook the home link has a query string on it like this: facebook.com/?ref=home when you click the link and navigate to the home page the query is automatically removed. However if I was to manually type in that link the query is NOT removed. Any idea on how they did this?

Answer 1

Easiest way in PHP:

$url = preg_replace('/?.*/', '', $url);

What Facebook does is probably a JavaScript thing, in that fashion:

if (location.href.match(/?.*/) && document.referrer) {
   location.href = location.href.replace(/?.*/, '');
}