js 中对于this 的理解的 经典案例

function Foo(){
   getName = function(){console.log(1);};
   return this;
}
Foo.getName = function(){console.log(2);};
Foo.prototype.getName = function(){console.log(3);};
var getName = function(){console.log(4);};
function getName(){console.log(5);}

Foo.getName();//2
getName();//4
Foo().getName();//1
getName();//1
new Foo.getName();//2
new Foo().getName();//3
new new Foo().getName();//3