Get last page visited

Question

I need to know if a person that comes to my website went from an another specific website. Example:

• User A visits www.youtube.com/myvideo and clicks on a link to my website.
• User B visits google, search my website and click the link.

Results Message on my page:

• User A: Welcome! You already know how it works, register now!
• User B: Welcome! Please watch our video first at www.youtube.com/myvideo

My question is:

1. Is it possible to know the last url the user visited before entering my page?
   I already tried $_SERVER['HTTP_REFERER'] with PHP, but it's not working correctly and I read that does not work on all browsers.
2. Is there any language or php script to get this url, working on all browser correctly?

Answer 1

Why not add a GET variable to the link on youtube - www.yoursite.com/?referrer=youtube

For discretion and appearance you could rewrite the URL to something like www.yoursite.com/youtube

Answer 2

The HTTP referer header is the only way. This is the data that is given to you in PHP via $_SERVER['HTTP_REFERER'].

Note that this header will work in most cases. Also note that it can be easily spoofed.