How do you live in such a bliss ignorance where supposedly an order of magnitude difference in performance between two state of the art browsers doesn't make you reconsider even for a second that you might have not written a working benchmark? :)

Sorry but unless you have deep knowledge of how both engines and browsers work (knowing how `appendChild` is actually implemented for starters), you simply cannot write a working benchmark. Even then, it's very hard and tedious.

If you don't have time to obtain such expertise, you could take a shortcut and compare realistic end-to-end benchmark. E.g. if your game runs at 210-270 fps in firefox but only at 30 fps in chrome, then you could claim that "firefox blows chrome out of the water".

It's very easy (just look at 80%+ of jsperfs) to construct benchmarks that don't look completely broken to the untrained eye but actually are. The common theme is the benchmark missing many aspects of realistic code and being reduced to measuring irrelevant optimizing compiling features. For example the benchmark could only be measuring how thorough the engine's dead code elimination pass is even though what you wanted to benchmark is string concatenation performance.