That's how all browser APIs are accessed from WASM, the DOM is nothing special in that regard. The only way for WASM to interact with the 'outside world' is thr

That's how all browser APIs are accessed from WASM, the DOM is nothing special in that regard. The only way for WASM to interact with the 'outside world' is through import and export function tables, and at least in the browser all functions in the import table will be Javascript functions. The only alternative would be for all browser Javascript APIs to get a separate "native C-like API" which could be plugged into the WASM import table and circumvent Javascript. That's basically how NaCl worked, with the downside that it only exposed a very small slice of browser APIs, for everything else one had to interact with Javascript via messaging, and this was a massively royal PITA. WASM does everything right in that regard.