canvas webgl

var aa = document.createElement('canvas');
ab = aa.getContext('webgl');
debugger;

var ac = {
    'contextName': ab.getParameter(ab['VERSION']),
    'glVersion': ab.getParameter(ab['VERSION']),
    'shadingLanguageVersion': ab.getParameter(ab['SHADING_LANGUAGE_VERSION']),
    'vendor': ab.getParameter(ab['VENDOR']),
    'renderer': ab.getParameter(ab['RENDERER']),
    'unmaskedVendor': null,
    'unmaskedRenderer': null,
    'antialias': ab.getContextAttributes()['antialias'],
    'extensions': ab.getSupportedExtensions(),
    'maxTextureSize': ab.getParameter(ab['MAX_TEXTURE_SIZE']),
    'maxViewportDims': ab.getParameter(ab['MAX_VIEWPORT_DIMS']),
    'maxCubeMapTextureSize': ab.getParameter(ab['MAX_CUBE_MAP_TEXTURE_SIZE']),
    'maxRenderbufferSize': ab.getParameter(ab['MAX_RENDERBUFFER_SIZE']),
    'maxVaryingVectors': ab.getParameter(ab['MAX_VARYING_VECTORS']),
    'maxVertexAttribs': ab.getParameter(ab['MAX_VERTEX_ATTRIBS']),
    'maxVertexTextureImageUnits': ab.getParameter(ab['MAX_VERTEX_TEXTURE_IMAGE_UNITS']),
    'maxVertexUniformVectors': ab.getParameter(ab['MAX_VERTEX_UNIFORM_VECTORS']),
    'aliasedLineWidthRange': ab.getParameter(ab['ALIASED_LINE_WIDTH_RANGE']),
    'aliasedPointSizeRange': ab.getParameter(ab['ALIASED_POINT_SIZE_RANGE']),
    'maxFragmentUniformVectors': ab.getParameter(ab['MAX_FRAGMENT_UNIFORM_VECTORS'])
};


ad = ab.getExtension('WEBGL_debug_renderer_info');
ac['unmaskedVendor'] = ab.getParameter(ad['UNMASKED_VENDOR_WEBGL']);
ac['unmaskedRenderer'] = ab.getParameter(ad['UNMASKED_RENDERER_WEBGL']);

let t_j = JSON.stringify(ac);
console.log(t_j);
debugger;