The web is stateless in the basic way it works. A person want to view a page and so their browser connects to the server and sends a request. The server responds by sending the page and then disconnects. There is no more contact between the two unless the user requests another page, at which time a new request is sent to the server. The server has no way of knowing that this is a continuation of the previous session without being told somehow that this is the case. There are two ways to do this, one is to set a cookie on the users machine which you can have the server check to see what their preferred setting is. The other way would be to encode the requesting URI send to the server to have that information in it, although that would probably be more difficult to accomplish the same thing.