Software regression has been a persistent issue in software development. Although numerous techniques have been proposed to prevent regression from being introduced before release, few are available to address regression as it occurs post-release. Therefore, identifying the root cause of regression has always been a time-consuming and labor-intensive task. We aim to deliver automated solutions for solving regressions based on tracing. We present Bugfox, a trace-based analyzer that reports functions as the possible cause of regression in JavaScript. The idea is to generate runtime trace with instrumented programs, then extract the differences between clean and regression traces, and apply two heuristic strategies based on invocation order and frequency to identify the suspicious functions among differences. We evaluate our approach on 12 real-world regressions taken from the benchmark BugsJS. First strategy solved 6 regressions, and second strategy solved other 4 regressions, resulting in an overall accuracy of 83% on test cases. Notably, Bugfox solve each regression in under 1 minute with minimal memory overhead (<200 Megabytes). Our findings suggest Bugfox could help developers solve regression in real development.