2.1.47 [ECMA-262-1999] Section 15.1, The Global Object
The global object does not have a [[Construct]] property; it is not possible to use the global object as a constructor with the new operator.
The global object does not have a [[Call]] property; it is not possible to invoke the global object as a function.
The values of the [[Prototype]] and [[Class]] properties of the global object are implementation-dependent.
In JScript 5.x the global object is a host object rather than a native object. The [[Class]] property of the global object has the value Object. The JScript 5.x global object does not actually have a [[Prototype]] property but for all situations described in this specification it behaves as if it had a [[Prototype]] property whose value was null. The global object does not inherit any properties from the built-in Object.prototype object.