The WebGLRenderingContext.isEnabled() method of the WebGL API tests whether a specific WebGL capability is enabled or not for this context.

By default, all capabilities except gl.DITHER are disabled.

cap

A GLenum specifying which WebGL capability to test. Possible values:

Constant	Description
gl.BLEND	Blending of the computed fragment color values. See WebGLRenderingContext.blendFunc().
gl.CULL_FACE	Culling of polygons. See WebGLRenderingContext.cullFace().
gl.DEPTH_TEST	Depth comparisons and updates to the depth buffer. See WebGLRenderingContext.depthFunc().
gl.DITHER	Dithering of color components before they get written to the color buffer.
gl.POLYGON_OFFSET_FILL	Adding an offset to depth values of polygon's fragments. See WebGLRenderingContext.polygonOffset().
gl.SAMPLE_ALPHA_TO_COVERAGE	Computation of a temporary coverage value determined by the alpha value.
gl.SAMPLE_COVERAGE	ANDing the fragment's coverage with the temporary coverage value. See WebGLRenderingContext.sampleCoverage().
gl.SCISSOR_TEST	Scissor test that discards fragments that are outside of the scissor rectangle. See WebGLRenderingContext.scissor().
gl.STENCIL_TEST	Stencil testing and updates to the stencil buffer. See WebGLRenderingContext.stencilFunc().

When using a WebGL 2 context, the following values are available additionally:

Constant	Description
gl.RASTERIZER_DISCARD	Primitives are discarded immediately before the rasterization stage, but after the optional transform feedback stage. gl.clear() commands are ignored.

A GLboolean indicating if the capability cap is enabled (true), or not (false).

gl.isEnabled(gl.STENCIL_TEST);
// false

To activate or deactivate a specific capability, use the WebGLRenderingContext.enable() and WebGLRenderingContext.disable() methods:

gl.enable(gl.STENCIL_TEST);
gl.disable(gl.STENCIL_TEST);

• WebGLRenderingContext.enable()
• WebGLRenderingContext.disable()