Code compiled to WASM can already access Javascript outside it. Obviously. Otherwise how could it do anything at all??
> Issues have been opened for native DOM bindings in WASM, but I am not sure if that work ever started.
I didn't say work had started on it. I just said that it is planned. See here for proof: http://webassembly.org/docs/high-level-goals/
> access browser functionality through the same Web APIs that are accessible to JavaScript
At this time, and for the foreseeable future, there are no plans with active code in development to implement WASM as a JavaScript replacement, at least to my knowledge.