Is this a per device sort of thing? Or is it based on the browser? Sorry for such a basic question but I cant seem to find a straight answer.
It is based on OpenGL ES 2.0, and according to the spec, it must support GLSL ES version 1.00. In fact that is all it supports.
On another note, this has been my general reference for GLSL features: http://www.shaderific.com/glsl/