function Shape(){}
            Shape.prototype.name='Shape';
            Shape.prototype.toString=function(){
                var result=[];
                if(this.constructor.uber){
                    console.log(this.constructor);
                    //TwoDShape 也執(zhí)行了一次toString()方法
                    result[result.length]=this.constructor.uber.toString();            
                }    
                result[result.length]=this.name;
                return result.join(', ')
            }
            
            function TwoDShape(){}
            var F=function(){};
            F.prototype=Shape.prototype;
            TwoDShape.prototype=new F();
            TwoDShape.prototype.constructor=TwoDShape;
            TwoDShape.uber=Shape.prototype;
            TwoDShape.prototype.name='2D Shape';
            
            function Triangle(side,height){
                this.side=side;
                this.height=height 
            }
            var F=function(){};
            F.prototype=TwoDShape.prototype;
            Triangle.prototype=new F();
            Triangle.prototype.constructor=Triangle;
            Triangle.uber=TwoDShape.prototype;
            Triangle.prototype.name='triangle';
            Triangle.prototype.getArea=function(){
                return this.side*this.height/2;
            }
            var my =new Triangle(5,10);
            console.log(my.toString());

為什么Triangle也會(huì)執(zhí)行一次toString()方法，我對(duì)這個(gè)流程不太清楚，麻煩幫我梳理一下。
主要是那個(gè)被重寫的toString()里面執(zhí)行下來不太明白。