AbstractThe World Wide Web, initially intended as a way to publish static hypertexts on the Internet, is moving toward complex applications. Static Web sites are being gradually replaced by dynamic sites, where information is stored in databases and non‐trivial computation is performed.In such a scenario, ensuring the quality of a Web application from the user's perspective is crucial. Techniques are being investigated for the analysis and testing of Web applications for such a purpose. However, a static analysis of the source code may be extremely difficult (and, in general, infeasible) because of the presence of dynamic generation of the HTML code that is part of the application under analysis.In this paper, a dynamic analysis technique is proposed for the extraction of a Web application model through its execution. Availability of statistical data about the accesses to the pages generated by the Web application is exploited for statistical testing, based on the recovered model. Test cases can be prioritized, so as to exercise the most frequently followed paths first. Moreover, statistical reproduction of the user's navigation paths allows for an estimation of the reliability of the application. Copyright © 2004 John Wiley & Sons, Ltd.