Been checking out WebGL as part of my more recent Saturday Morning Project. And as far as I can surmise, WebGL seems to be an interface that exposes GPU hardware buffers to the browser. And javascript in this context, is basically utilized to push floating-point values to vertex buffers, and shuttling them through the C(?) foreign-function interface into the GL library.
Here's the current code state of my fiddling with a simple, bare bones WebGL context:
https://github.com/miketon/webGL
Here's a mindmap of my current understanding OpenGL functions and hardware registers:
http://www.mindomo.com/view.htm?m=fe720acc4ba34b7bb49c8524b427c768
There's a lot to love about the how graphics development on the web is trending. It feels like a reset/re-invention of the industry ~10 years ago.