8. A computer-readable storage medium configured with data and with instructions that when executed by at least one processor causes the processor(s) to perform a technical process to facilitate debugging or testing a locally cached web application, the process comprising the steps of: (A) automatically replaying a previously recorded scenario to the locally cached web application, the locally cached web application including a plurality of functions, thereby (B) exercising a subset of the web application functions through their execution by at least one processor and (C) producing a scenario behavior from the web application; (D) automatically trimming from the web application at least one dead function, namely, a web application function which was not exercised during step (B), thereby (E) providing a trimmed version of the web application; (F) selecting a web application function which was exercised during step (B) and then (G) disabling execution of the selected exercised function; (H) attempting to again replay the previously recorded scenario to the web application, but with the selected function disabled even though it was exercised in step (B), thereby (J) producing a candidate behavior from the web application; when the step (J) candidate behavior matches the step (C) scenario behavior then (K) removing the disabled function, thereby (L) providing a trimmed and reduced version of the web application for debugging; and when the step (J) candidate behavior does not match the step (C) scenario behavior then (M) re-enabling the disabled function, thereby (N) providing a trimmed and reduction-tested version of the web application for debugging; wherein the process includes interleaving multiple instances of attempting the trimming step (D) with multiple instances of the removing step (K) for which candidate behavior matches the scenario behavior.
13. The storage medium of claim 8 , wherein at least two instances of the removing step (K) occur between two successive attempts at trimming step (D).