(blend4web) Refraction of content outside the canvas, is it possible?

Question

Blender

Friends! I recently started using Blend4Web software. The tool is interesting and functional, but I just can't figure out a few questions:
1) Is it possible to implement the refraction of the content of the site, which has a canvas on top?
2) Is it possible to implement refraction of the background of the canvas if the object has the appropriate function (crystal for example)
3) If there are experts in Blend4web, what are the ways to implement refraction along the edges of the crystal? Maybe I'm doing something wrong.
Connoisseurs of WebGL do not need to offer - "write in clean", this option is not suitable)