From the Author:
WebGL playground is a straightforward idea: type in
your WebGL script and see the results. But the cool
part is that the editor and the results are just on
the same page and that you get a handful of features
that make your life easier.
the GLSL vertex/fragment shaders (if you have any)
at the same time in a convenient way. Everything is
organized, formatted and highlighted properly, just
as you would like!
your effects, combine multiple fragment and vertex
shaders, handle user input etc.