// FOR UNITTEST
return '\\' + 2;

var attributes = "\\[" + a + "*(" + b + ")(?:" + c +
		// Operator (capture 2)
		"*([*^$|!~]?=)" + d +
		// "Attribute values must be CSS identifiers [capture 5] or strings [capture 3 or capture 4]"
		"*(?:'((?:\\\\.|[^\\\\'])*)'|\"((?:\\\\.|[^\\\\\"])*)\"|(" + e + "))|)" + f +
		"*\\]";

var a = 200;