How to read client registery values using php script

Hi all. i want to make a php script that can read certian client registery values but i do not know how to write it. I be happy if an expert show me how.i think it could be done because i have seen html pages that show what version of windows and what browser ect... and i assume that they got this from the registry.Thanks

This is impossible, if it were it would be a major security risk. The infomation you mentioned is not read fromt he registry but is read from the $_SERVER['USER_AGENT'] variable. If you want to store basic information on the clients mahcine then the only was this is possible is to use cookies.

http://uk.php.net/manual/en/function.setcookie.php