function Dog(name, age) {
            this.name = name;
            this.age = age;
            return {
                name: 'pan',
                age: 18
            }
        }
 console.log(new Dog('小黃', 2)) //   {name: "pan", age: 18}

上面代碼可以看出構(gòu)造函數(shù)有返回值且為對象時,會返回這個對象.