Some clients are smarter than others. Typically, WWW clients know a number of protocols, such as FTP, Gopher, NNTP and, of course, HTTP . A list of WWW clients is also available from CERN in Geneva. At least on a Unix system that is not difficult to do. WWW supports format negotiations between server and client for case when information is available in several formats.
Interactive forms are possible with a range of buttons, radio-buttons, and input fields.
Each page is either a menu, a query form, or an information page. Pages can indicate that they need an external application to be displayed properly. A story can be distributed over several machines, without the user being aware of that. In contrast to the other systems described in this chapter VTX is a commercial system, which means that license fees have to be paid for every VTX server and every reader program on another computer. KUB-gids cannot be accessed from the outside, except by logging in to one of the university's machines.