This tutorial describes how to use the <canvas> element to draw WebGL graphics, starting with the basics. The examples provided should give you some clear ideas what you can do with WebGL and will provide code snippets that may get you started in building your own content.
The WebGLProgram is part of the WebGL API and is a combination of two compiled WebGLShaders consisting of a vertex shader and a fragment shader (both written in GLSL). These are then linked into a usable program.
The ANGLE_instanced_arrays extension is part of the WebGL API and allows to draw the same object, or groups of similar objects multiple times, if they share the same vertex data, primitive count and type.
The EXT_blend_minmax extension is part of the WebGL API and extends blending capabilities by adding two new blend equations: the minimum or maximum color components of the source and destination colors.
The EXT_shader_texture_lod extension is part of the WebGL API and adds additional texture functions to the OpenGL ES Shading Language which provide the shader writer with explicit control of LOD (Level of detail).