WebAssembly has nothing to do with JavaScript. When people make this association it is clear they are painfully unaware of what each (or both) technologies are.
WebAssembly is a replacement for Flash, Silverlight, and Java Applets.
Flash, Silverlight and Java Applets all provided APIs and functionality above and beyond what JavaScript or the browser DOM provides. WebAssembly is the opposite, as it is much more restricted than JavaScript. WASM is a sandbox inside a sandbox.
I am extremely unclear on whatever point you're trying to make, here, because it really does seem to come from a place of ignorance on WASM and JS. It makes no sense.
It seems like you're claiming, in a really roundabout way, that WASM will never have DOM access, even though it's planned[1]. There are even VDOMs[2] for WASM already. Future WASM implementations that include DOM access can absolutely, and for many folks will, replace Javascript.
> It seems like you're claiming, in a really roundabout way, that WASM will never have DOM access
I am not going to say never. It does not now and will not for the foreseeable future though. I know DOM interop is a popular request, but nobody has started working on it and it isn't a priority.
Part of the problem in implementing DOM access to a unrestricted bytecode format is security. Nobody wants to relax security so that people who are JavaScript challenged can feel less insecure.
Which of the security concerns browser Javascript deals with do you think are intrinsic to the language, as opposed to the bindings the browser provides the language? If the security issues are in the bindings (ie: when and how I'll allow you to originate a request with credentials in it), those concerns are "portable" between languages.
Not sure if this is directly relevant, but there have been all sorts of type confusion bugs when resizing arrays, etc. Stuff in the base language. They exist independent of API, but merely because the language is exposed.
It isn't due to the language but to context of known APIs provided to the language that can only be executed a certain way by the language.
How would a browser know to restrict a web server compiled into bytecode specifically to violate same origin? The browser only knowns to restrict this from JavaScript because such capabilities are allowed only from APIs the browser provides to JavaScript.
I really don't understand your example. Are you proposing a web server running inside the browser as a WebAssembly program, and the browser attempting to enforce same origin policy against that server? That doesn't make much sense.
Yep, it doesn't make sense and that is the problem. There is no reason why you couldn't write a web server in WASM that runs in an island inside the browser to bypass the browser's security model.
It will take more than just DOM access to replace Javascript. Just off the top of my head you'd also need access to the event loop, XHR, websockets, audio & video, webRTC, Canvas, 3D, Filesystem, cookies & storage, encryption, Web Workers and more.
That's an arbitrary distinction that's driven by developer group politics, not a meaningful technical distinction. (Much like the old Rubyist, "It's an interpreter, not a VM.")
Machine languages were originally intended to be used by human beings, as were punch cards and assembly language. There's no reason why a person couldn't program in bytecode. In fact, to implement certain kinds of language runtime, you basically have to do something close to this. Also, writing Forth is kinda close to directly writing in Smalltalk bytecode. History also shows us that what the language was intended for is also pretty meaningless. x86, like a lot of CISC ISAs, was originally designed to be used by human beings. SGML/XML was intended to be human readable, and many would debate that it succeeded.
> That's an arbitrary distinction that's driven by developer group politics
Not at all. JavaScript is a textual language defined by a specification. Modern JavaScript does have a bytecode, but it is completely proprietary to the respective JIT compiler interpreting the code and utterly unrelated to the language's specification.
> There's no reason why a person couldn't program in bytecode.
The point is that a "textual language defined by a specification" can serve the exact same purpose that a bytecode does. And JavaScript is very much on this path.
That is this discussion, because the fact that people program directly in JavaScript does not prevent it from being in the same class of things as a bytecode.
WebAssembly is a replacement for Flash, Silverlight, and Java Applets.