We have some exciting news to share with you all, recently I have managed to get MonoGame running inside the web browser. The web version of MonoGame requires WebGL 2 and has support for Chrome, Firefox, Opera and Vivaldi web browsers. You can see the good old Platformer2D XNA sample running on the following link: http://www.monogame.net/webdemo/ (source code also available)
Currently the web version is getting compiled to JS using Bridge.NET, this is however only a temporary solution and we'll switch to using WebAssembly (WASM) once C# -> WASM conversion gets to a more stable point. This will greatly improve performance.
An Alpha version will become available on October 12th with easy to use templates, so keep your eyes peeled. If you are interested in following the news regarding this, you can do so in one of the following ways: