Currently the Emscripten “test” HTML page is unattractive and doesn’t provide a way for the user to see the download progress of the .js file. A simple ‘loading’ screen that shows a progress meter while resources are downloading (similar to the plugin’s) would be useful.
The only problem is that dependencies such as models, textures, etc. are downloaded after the .js file begins running. And, as far as I know, Emscripten doesn’t provide a way for us to monitor the progress of that. (If you look at the code of the test page, there appears to be a sort of progress/loading indication for these, but the actual compiled script never actually calls those functions.)