In this paper we review five years of research in the field of automated crawling and testing of web applications. We describe the open source Crawljax tool, and the various extensions that have been proposed in order to address such issues as cross-browser compatibility testing, web application regression testing, and style sheet usage analysis. Based on that we identify the main challenges and future directions of crawl-based testing of web applications. In particular, we explore ways to reduce the exponential growth of the state space, as well as ways to involve the human tester in the loop, thus reconciling manual exploratory testing and automated test input generation. Finally, we sketch the future of crawl-based testing in the light of upcoming developments, such as the pervasive use of touch devices and mobile computing, and the increasing importance of cyber-security.@en