You can see the difference in the WebAssembly Benchmark: http://iswebassemblyfastyet.com
Firefox WASM: 1809ms
Chrome WASM: 2855ms
Edge WASM: 12872ms
Firefox JS: 5413ms
Chrome JS: 4779ms
Edge JS: 8512ms
Firefox linux (v62.0.3)1904
From article: "This means that in the latest version of Firefox * Beta *, calls between JS and WebAssembly are faster than non-inlined JS to JS function calls."
Firefox linux 2132