IE6-8 实现 Function protoypte bind问题

[myseemydog]

   
		Function.prototype.bind = function (oThis) {
		
		    var aArgs = Array.prototype.slice.call(arguments, 1), 
			fToBind = this, 
			fNOP = function () {},
			fBound = function () {
			  return fToBind.apply(this instanceof fNOP && oThis
						 ? this
						 : oThis || window,
					       aArgs.concat(Array.prototype.slice.call(arguments)));
			};
		
		    fNOP.prototype = this.prototype;
		    fBound.prototype = new fNOP();
		
		    return fBound;
		  };
		  
		  
		  var person = {
			age:10,
			getAge:function(){
				return this.age;
			}
		  }
		//  
		var boundGetAge = person.getAge.bind(person);

 fNOP.prototype = this.prototype;
 fBound.prototype = new fNOP();

这里问什么要把这个返回出来的函数原型指向先前对象里面getAge的原型呢？


有大大说是EMCA262标准、、还有人说是断开引用。
求解

[myseemydog]

。。Any 大神？