The convergence of desktop, mobile and web application development has resulted in new types of software systems. These new systems are built to leverage the World Wide Web, and they allow the use of dynamically downloaded applications and services from any type of terminal, including desktop computers and mobile devices. At the same time, the JavaScript language has become the de facto programming language of the Web. In this paper we introduce Lively for Qt – a practical JavaScript application platform that supports the development of highly interactive mobile web applications and mashups that run both in the web browser and as standalone “phonetop” applications. Additionally, we present our vision for mobile web applications, as well as summarize the experiences and lessons learned during the development of the new system. Categories and Subject Descriptors D.2.2 [Software Engineering]: Design Tools and Techniques – modules and interfaces, software libraries, user interface...