«Вирусы» в расширениях на примере FastProxy

let getWebglFingerprint = () => {
	var a;
	var e = function(e) {
		a.clearColor(0, 0, 0, 1); 
		a.enable(a.DEPTH_TEST); 
		a.depthFunc(a.LEQUAL);
		a.clear(a.COLOR_BUFFER_BIT | a.DEPTH_BUFFER_BIT);
		
		return '[' + e[0] + ', ' + e[1] + ']';
	};
	a = getWebglContext();
	if ( !a ) return null;
	
	var t = [];
	var i = a.createBuffer();
	
	a.bindBuffer(a.ARRAY_BUFFER, i);
	
	var n = new Float32Array([-.2, -.9, 0, .4, -.26, 0, 0, .732134444, 0]);
	a.bufferData(a.ARRAY_BUFFER, n, a.STATIC_DRAW); 
	i.itemSize = 3; 
	i.numItems = 3;
	
	var r = a.createProgram();
	var o = a.createShader(a.VERTEX_SHADER);
	a.shaderSource(o, "attribute vec2 attrVertex;varying vec2 varyinTexCoordinate;uniform vec2 uniformOffset;void main(){varyinTexCoordinate=attrVertex+uniformOffset;gl_Position=vec4(attrVertex,0,1);}"); 
	a.compileShader(o);
	
	var s = a.createShader(a.FRAGMENT_SHADER);
	a.shaderSource(s, "precision mediump float;varying vec2 varyinTexCoordinate;void main() {gl_FragColor=vec4(varyinTexCoordinate,0,1);}"); 
	a.compileShader(s); 
	a.attachShader(r, o); 
	a.attachShader(r, s); 
	a.linkProgram(r); 
	a.useProgram(r); 
	r.vertexPosAttrib = a.getAttribLocation(r, 'attrVertex'); 
	r.offsetUniform = a.getUniformLocation(r, 'uniformOffset'); 
	a.enableVertexAttribArray(r.vertexPosArray); 
	a.vertexAttribPointer(r.vertexPosAttrib, i.itemSize, a.FLOAT, false, 0, 0); 
	a.uniform2f(r.offsetUniform, 1, 1); 
	a.drawArrays(a.TRIANGLE_STRIP, 0, i.numItems);
	try {
		t.push(a.canvas.toDataURL())
	} catch (a) {}
	t.push('extensions:' + (a.getSupportedExtensions() || []).join(';')); 
	t.push('webgl aliased line width range:' + e(a.getParameter(a.ALIASED_LINE_WIDTH_RANGE))); 
	t.push('webgl aliased point size range:' + e(a.getParameter(a.ALIASED_POINT_SIZE_RANGE))); 
	t.push('webgl alpha bits:' + a.getParameter(a.ALPHA_BITS)); 
	t.push('webgl antialiasing:' + (a.getContextAttributes().antialias ? 'yes' : 'no')); 
	t.push('webgl blue bits:' + a.getParameter(a.BLUE_BITS)); 
	t.push('webgl depth bits:' + a.getParameter(a.DEPTH_BITS)); 
	t.push('webgl green bits:' + a.getParameter(a.GREEN_BITS)); 
	t.push('webgl max anisotropy:' + function(a) {
			var e = 
				a.getExtension('EXT_texture_filter_anisotropic') || 
				a.getExtension('WEBKIT_EXT_texture_filter_anisotropic') || 
				a.getExtension('MOZ_EXT_texture_filter_anisotropic');
			if (e) {
					var t = a.getParameter(e.MAX_TEXTURE_MAX_ANISOTROPY_EXT);
					return 0 === t && (t = 2), t
			}
			return null
	}(a)), 
	t.push('webgl max combined texture image units:' + a.getParameter(a.MAX_COMBINED_TEXTURE_IMAGE_UNITS));
	t.push('webgl max cube map texture size:' + a.getParameter(a.MAX_CUBE_MAP_TEXTURE_SIZE));
	t.push('webgl max fragment uniform vectors:' + a.getParameter(a.MAX_FRAGMENT_UNIFORM_VECTORS));
	t.push('webgl max render buffer size:' + a.getParameter(a.MAX_RENDERBUFFER_SIZE));
	t.push('webgl max texture image units:' + a.getParameter(a.MAX_TEXTURE_IMAGE_UNITS));
	t.push('webgl max texture size:' + a.getParameter(a.MAX_TEXTURE_SIZE));
	t.push('webgl max varying vectors:' + a.getParameter(a.MAX_VARYING_VECTORS));
	t.push('webgl max vertex attribs:' + a.getParameter(a.MAX_VERTEX_ATTRIBS));
	t.push('webgl max vertex texture image units:' + a.getParameter(a.MAX_VERTEX_TEXTURE_IMAGE_UNITS));
	t.push('webgl max vertex uniform vectors:' + a.getParameter(a.MAX_VERTEX_UNIFORM_VECTORS));
	t.push('webgl max viewport dims:' + e(a.getParameter(a.MAX_VIEWPORT_DIMS)));
	t.push('webgl red bits:' + a.getParameter(a.RED_BITS));
	t.push('webgl renderer:' + a.getParameter(a.RENDERER));
	t.push('webgl shading language version:' + a.getParameter(a.SHADING_LANGUAGE_VERSION));
	t.push('webgl stencil bits:' + a.getParameter(a.STENCIL_BITS));
	t.push('webgl vendor:' + a.getParameter(a.VENDOR));
	t.push('webgl version:' + a.getParameter(a.VERSION));
	
	try {
		var l = a.getExtension('WEBGL_debug_renderer_info');
		l && t.push('webgl unmasked vendor:' + a.getParameter(l.UNMASKED_VENDOR_WEBGL)); 
		t.push('webgl unmasked renderer:' + a.getParameter(l.UNMASKED_RENDERER_WEBGL));
	} catch (a) {}
	if (!a.getShaderPrecisionFormat) return t.join('~');
	
	['FLOAT', 'INT'].forEach( e => {
		['VERTEX', 'FRAGMENT'].forEach( i => {
			['HIGH', 'MEDIUM', 'LOW'].forEach( n => {
				['precision', 'rangeMin', 'rangeMax'].forEach( r => {
					var o = a.getShaderPrecisionFormat(a[i + '_SHADER'],
					a[n + '_' + e])[ r ];
					if( 'precision' !== r ) r = 'precision ' + r;
					var s = ['webgl ', i.toLowerCase(), ' shader ', n.toLowerCase(), ' ', e.toLowerCase(), ' ', r, ':', o];
					
					t.push(s.join(''))
				});
			});
		});
	});
	
	return t.join('~');
};