It seems like they "could" complement each other, but that's not a defining characteristic of WASM. WASM, as I understand it, essentially allows me to take my higher-level language like Python/Haskell/Perl/(Maybe also JS) and compile an AST that can be interpreted by the engine on the client-side. Which is great for Python/Haskell/Perl developers that they no longer have to pay the toll of learning/sharing/contributing to JS - they are Haskell devs, maybe they shouldn't have to contribute to JS. We can call that a good thing, but let's not pretend that doesn't marginalize JS (which - again!! - maybe it should). "But they still don't have access to the DOM" is not much of an impediment to that Perl dev, and means as your run-of-the-mill guy I now have to debug the Perl-produced WASM AST (Maybe pretty-printing will let me read it in 5 hours instead of 12, but I'm still reading binary/AST which does not seem like an awesome time) and the cruft from whatever Perl-WASM binding library they forked from Github. Again - I know this makes life better for that Perl dev, and maybe he/she deserves it. But unless I'm missing something, I don't see how allowing that dev to (basically) skip JS in their path from whatever IDE Perl devs use to the Web makes WASM "chummy" with Javascript. In fact, it seems like now that dev will start making/contributing to libraries that conform to their stack (Perl-specific web libraries that compile to WASM). Now if I want to contribute to that library - which is now a part of the web - I have to learn Perl. Before, that Perl dev would have had to learn Javascript - which I know sucks for them - but it was good for me and good for Javascript... and I would say "good for the web". We were all speaking the same language, which led to an explosion of learning and collaboration. Sure, .3 != .1 + .2 But it was that way for all of us. Now everyone is going to go back to their own little feifdoms and just tipping their hat to JS along the way with a lightweight DOM binding port.
Yeah, the VM is the same but allows low-level JS instructions to run. So next step, is to build a <your favorite language> to webasm transpiler and not have to use JS again ... :) I believe emscriptem is already doing this for C/C++
