How do you access browser history?

Some e-Marketing tools claim to choose which web page to display based on where you were before. That is, if you've been browsing truck sites and then go to Ford.com, your first page would be of the Ford Explorer.

I know you can get the immediate preceding page with HTTP_REFERRER, but how do you know where they were 6 sites ago?

Solution 1:

Javascript this should get you started: http://www.dicabrio.com/javascript/steal-history.php
There are more nefarius means to: http://ha.ckers.org/blog/20070228/steal-browser-history-without-javascript/
Edit:I wanted to add that although this works it is a sleazy marketing teqnique and an invasion of privacy.

Solution 2:

Unrelated but relevant, if you only want to look one page back and you can't get to the headers of a page, then document.referrer gives you the place a visitor came from.

Solution 3:

You can't access the values for the entries in browser history (neither client side nor server side). All you can do is to send the browser back or forward a number of steps. The entries of the history are otherwise hidden from programmatic access.

Also note that HTTP_REFERER won't be there if the user typed the address in the URL bar instead of following a link to your page.