The requirements of modern website design provide significant incentives for both web development tools and usability evaluation methodologies. One such development tool, Molly, has been previously developed for rapid website design. Its lack of usability evaluation functionality made it a promising candidate for this effort. As a proxy for the user's focus of attention, eye tracking is the gold standard of usability evaluation; however, this approach requires specialized equipment under experimental conditions. A more workable proxy is mouse tracking. Four rounds of prototyping were conducted to devise a practical demonstration of instrumenting web pages with lightweight code capable of capturing real time mouse event data and transmitting such data transparently and asynchronously to a server for storage and later analysis. The final prototype was then integrated into the Molly framework to provide web page developers with a new Molly tag that instruments any page containing such a tag for event capture, with captured data being stored in the Molly database for further analysis. Basic administrative and reporting pages were also implemented. Opportunities for extending Molly mouse tracking functionality are plentiful and include polishing the elegance of the Molly event tracking code, refining the capabilities of the administrative page, extending support to non-standards compliant browsers, enhancing reporting capabilities, creating analysis and playback tools, and providing data exporting capabilities, such as web services, to facilitate dissemination of captured data.