This paper addresses enhancing HTML and XML with adaptation
functionalities. The approach consists in using the path selectors
of the HTML and XML style sheet languages CSS and XSLT for expressing
content and navigation adaptation. Thus, the necessary extensions of
the selector languages are minimal (a few additional constructs suffice),
the processors of these languages can be kept almost unchanged, and no
new algorithms are needed. In addition, XML is used for expressing the
user model data like browsing history, browsing environment (such as
device, location, time, etc.), and application data (such as user performances
on exercises). The goal of the research presented here is not to
propose novel forms or applications of adaptation, but instead to extend
widespread web standards with adaptation functionalities. Essential features
of the proposed approach are its simplicity and both the upwards
and downwards compatibility of the extension