AJAX is a promising and rapidly evolving approach for building highly interactive web applications. In AJAX, user interface components and the event-based interaction between them form the founding elements, whereas in classic web applications the notions of web pages and hypertext links are central. Therefore modelling AJAX requires a different approach than what the current web modelling tools are providing. In this paper we propose a UML scheme for modelling AJAX user interfaces based on the MDA approach. We adopt ANDROMDA for creating an AJAX cartridge to generate an entire AJAX-based web application with automatic back-end integration. The implementation of this cartridge is a work in progress.@en