The only actual numbers I've seen, from emscripten author Alon Zakai, show gzipped minified emscripten JS output as comparable in size to gzipped native code:

The only actual numbers I've seen, from emscripten author Alon Zakai, show gzipped minified emscripten JS output as comparable in size to gzipped native code: http://mozakai.blogspot.com/2011/11/code-size-when-compiling-to-javascript.html http://mozakai.blogspot.com/2011/11/code-size-when-compiling...