The WebGLRenderingContext.stencilMask() method of the WebGL API controls enabling and disabling of both the front and back writing of individual bits in the stencil planes.
The WebGLRenderingContext.stencilMaskSeparate() method of the WebGL API controls enabling and disabling of front and/or back writing of individual bits in the stencil planes.
The WebGLRenderingContext.validateProgram() method of the WebGL API validates a WebGLProgram. It checks if it is successfully linked and if it can be used in the current WebGL state.
The WebGLRenderingContext.vertexAttribPointer() method of the WebGL API specifies the data formats and locations of vertex attributes in a vertex attributes array.
The WebGLRenderingContext.viewport() method of the WebGL API sets the viewport, which specifies the affine transformation of x and y from normalized device coordinates to window coordinates.
The WebGLRenderingContext.copyTexSubImage2D() method of the WebGL API copies pixels from the current WebGLFramebuffer into an existing 2D texture sub-image.