$_SERVER['HTTP_REFERER'] variable which should contain the referring URL. Please note that this is not tamper-proof or fail-safe as the
Http-Referer header can easily been changed or modified by a client.
Just googled for
phpinfo (because chanes were high that I get a
phpinfo() page that shows the
$_SERVER['HTTP_REFERER'] variable) to show you how the
Http-Referer will look like:
$_SERVER['HTTP_REFERER'] = "http://www.google.de/search?hl=de&q=phpinfo&btnG=Google-Suche&meta="
As you see, you can also extract the search term used in the google query (or detect if the search was initiated by the Google Chrome address bar)…