opengl reference for emscripten

[Alessio Mochi]

Hello,

I created an opengl context with

 ctx = emscripten_webgl_create_context("#canvas", &attr) and I would like to manage the component entirely from emscripten. 

Is there a reference book to understand which opengl functions are supported by emscripten in hadware mode or a similar documentation? What's shader support?

Thanks in advance.