JavaScript has gone from being a mechanism for providing dynamic web pages to an important component of many web applications. Currently one of the most popular type of web applications is so-called social networks, e.g., Facebook, Twitter, and MySpace. However, the workload and execution behavior of JavaScript in this context have not been fully explored or understood. In this paper we present a methodology for characterizing the JavaScript execution behavior in interactive web applications using deterministic execution of use cases. Then, we apply this methodology to evaluate a set of social network applications and compare their behavior to a set of established JavaScript benchmarks. Our results confirm previous studies that the execution behavior of social networks differ from established benchmarks. In addition, we identify one novel difference not published before, i.e., the use of anonymous functions in web applications.