//构造函数中，如果返回的是一个对 象，那么就保留原意. 如果返回的是非对象，比如数字、布尔和字符串，那么就返回 this，如果没有 return 语句，那么也返回this.

         var myFun1 = function(){

            this.name = "LiuYashion1";

            self1 = this;

            return 'BOY'

        }

        var myFun2 = function(){

            this.name = "LiuYashion2";

            return {

                sex:'BOY'

            };

        }

        var temp1 = new myFun1();

        var temp2 = new myFun2();

        console.log(temp1);              //myFun1 {name: "LiuYashion1"}

        console.log(temp1.name);    //LiuYashion1

        console.log(temp2);              //Object {sex: "BOY"}

        console.log(temp2.name);    //undefined

        console.log(temp2.sex);       //BOY

        console.log(myFun1());        //BOY

        console.log(myFun2());        //Object {sex: "BOY"}