FeedLack finds scenarios where web applications ignore user input by applying static program analysis to JavaScript, HTML, and CSS. For example, the calculator below (archived from here) is rife with interactions that accept user input, but fail to provide output explaining what action the calculator took. These interactions are difficult to find by just reading code, but FeedLack can automatically analyzing the way that the application handles input. In this case, it found 54 situations in which the calculator might lack feedback. Click on the warnings and use the up and down arrow keys to read through the warning details.

See the research paper from CHI 2010 for details on how the analysis works. Questions? Contact Andrew J. Ko, Assistant Professor at the University of Washington Information School.