My lab (SurfLab) manages a program called BezierView which is used for rendering different kinds of Bezier surfaces (triangular, tensor-product, rational, etc.). BezierView has not been updated for a few years, so me and a few other colleagues decided to update the program using WebGL instead.
Now instead of downloading BezierView to your own computer and running a .exe file, you can just run it online through a webpage. You can find the still-being-updated version here. For now you can view tensor-product, triangular and rational patches along with polyhedra. It is being currently updated to include a better interface and to have support for all types.
BezierView was developed using the excellent Three.js library. I highly recommend using it if you are developing a WebGL application.
The source code is available on GitHub.
You can find BezierView here.