[mehrzad]

https://html5test.com/results/desktop.html

Why does Firefox do so poorly? ;_; Mozilla is such a good organization (but to be fair can only survive with Google).

[khuey]

Because much of what it tests isn't in HTML5. Some of what it tests isn't even standards track (e.g. WebSQL). The tests are also usually pretty superficial and test things like "does this property exist", not "does this feature work".