Abstract. Adaptive websites usually change as effect of user navigational actions. Most current web engineering approaches (which consider personalization) allow to detect basic user browsing behaviour (e.g. user click on a link) but don’t consider the definition of (complex) behaviour events or user behaviour pattern recognition. In this paper, we use a method independent language called PRML to specify behaviour aware websites. PRML evolved out the experience of OO-H and was designed to be a generic personalization specification method that can be reused for different web design approaches. PRML allows the personalization when a complex behaviour event is triggered (i.e. a sequence of links) and also allows the definition and recognition (at runtime) of user behaviour patterns. 1.