In the asm.js spec, see that for variable type annotations, it says:
Lookup(Δ, Γ, f) must be fround and n must be a floating-point literal with the character . in its source.
This is not how it is used though, as Emscripten generates and Firefox validates without the '.' character. My initial thought was that maybe the validation rule was actually being treated as any fround(NumericLiteral), which would essentially be the integer range [-2^31, 2^32), or any numeric literal with a '.' present.
However, this does not seem to be the case either, as Firefox validates any numeric literal, without respect to how NumericLiteral is defined in the spec or used elsewhere. To me this seems inconsistent, so what should the behavior be? My opinion on the matter is that it should be handled the same as NumericLiteral elsewhere.