Recording and replaying user navigations greatly simplifies the testing process of web applications and, consequently, greatly contributes to improving usability, robustness and assurance of these applications. Implementing such replaying functionalities with modern web technologies such as AJAX is very hard: the GUI may change dynamically as a result of a myriad of different events beyond the control of the replaying machinery and even locating a given GUI element across different executions may be impossible.
In this work we propose a tool that overcomes these problems and is able to handle real-world web sites based on AJAX technology. Recording occurs automatically, i.e., the user navigates with a normal browser and need not take any specific action. Replaying a previously recorded trace occurs programmatically, based on several heuristics that make the tool robust with respect to DOM variance while at the same time maintaining the ability to detect whether replaying has become impossible---perhaps because the target web site has changed too much since the recording. The entire procedure is fully transparent to the target web site. We also describe the use of our tool on several web applications including Facebook, Amazon and others.