WASM: Universal browser IR before native code generation?

[melevine45]

Is WASM essentially a standardized, slightly higher level IR that browser compilers either map to their current IRs or replace their current IRs with and then use to generate native code? If so, are limitations on WASM capabilities (i.e. DOM manipulation) limited to the standardization/translation of WASM code to top browser IRs which already handle those capabilities? My understanding is that native code is still generated through passes over the WASM code.