something interesting with prototype and window

1. 问题一

　　var obj = {};
　　function Con()
　　{
　　};
　　Con.prototype = obj;
　　var a =  new Con();
　　document.writeln((a.prototype === Object.prototype.prototype).toString());　　//true
　　document.writeln((a.prototype === obj.prototype).toString());　　　　　　　　　//true
　　document.writeln((obj.prototype == Object.prototype).toString());　　　　　　　　　　　　//false
　　document.writeln((obj.isPrototypeOf(a) && Object.prototype.isPrototypeOf(a)).toString());　　//true

Object -> Object.prototype(Object.isPrototypeOf(Object))
obj -> Object.prototype.prototype(Object.prototype.isPrototypeOf(obj))
a -> obj.prototype === Object.prototype.prototype(Object.prototype.isPrototypeOf(a))
Function -> Object.prototype.prototype(Object.prototype.isPrototypeOf(Function))

2. 问题二 

IE 下专属问题

Why this returns a false?? what's more, window.window == window.window.window...this is true!!

window.window.window == window.window.window.window also returns true!!~~~what's the special in window? quite interesting~~