1 function extend(child,parent){ 2     var F=function(){} 3     F.prototype=parent.prototype; 4     child.prototype=new F(); 5     child.prototype=child; 6     child.uber=parent.prototype; //uber指向父对象的原型。方便子对象调用父对象原型中的重写的方法。 7 } 8 function Shape(){} 9 Shape.prototype.name="Shape";10 Shape.prototype.color="blue";11 12 function circle(radius){13     this.radius=radius;14 }15 16 circle.prototype.name="circle";17 circle.prototype.getS=function(){18     return this.radius*this.radius*3.14;19 }20 extend(circle,Shape);21 22 var cir=new circle(2);23 alert(cir.name);   //"circle"24 alert(cir.color);    //"blue"25 alert(cir.uber.name);    //"Shape"26 alert(cir.getS()) //"12.56"

 1 var cir=new circle(2); 2 var shape1=new Shape(); 3 cir.prototype.name="this is circle"; 4  5  6 for(var i in shape1){ 7      if(!shape1.hasOwnProperty(i)){  //遍历非实例属性 8          console.log(i+"："+shape1[i]); 9      }10 }11 12 //name:circle13 //color:blue14 //getS:function (){15     return this.radius*this.radius*3.14;16 }17 18 19 for(var i in cir){20      if(!cir.hasOwnProperty(i)){21         console.log(i+"："+cir[i]);22      }23 }24 25 //name:circle26 //color:blue27 //getS:function (){28     return this.radius*this.radius*3.14;29 }.