window.onload = function() {
        testCons();
        Object.prototype.Clone = function() {
            var objClone;
            if (this.constructor == Object) {
                objClone = new this.constructor();
            } else {
                // objClone=new this.constructor(this.valueOf()); 
                objClone = this.valueOf();//似乎这样也没错？
            }
            for (var key in this) {
                if (objClone[key] != this[key]) {
                    if (typeof(this[key]) == ‘object‘) {
                        objClone[key] = this[key].Clone();
                    } else {
                        objClone[key] = this[key];
                    }
                }
            }
            objClone.toString = this.toString;
            objClone.valueOf = this.valueOf;
            return objClone;
        }
        var obj1 = {
            key1: 1,
            key2: {
                key21: 21,
                key22:"22",
                key23:{
                    key221:221
                }
            }

        }
        obj2 = obj1.Clone();
        console.log(obj2);
        console.log(typeof obj2.key2.key21);
    }

    function testCons() {
        var num = 5;
        console.log(num.constructor(6)); //6
        console.log(typeof num.constructor(6)); //number
        console.log(num.constructor);//function Number() { [native code] } 
        console.log(num.constructor==Number);//true 

        n=new num.constructor(6);
        console.log(typeof n); //object
        console.log(n.constructor);//function Number() { [native code] } 
        console.log(n.constructor==Object);    //false 
        //因此用constructor来判断类型是最合适不过的        

        function Person(name) {
            this.name = name;
        }
        p1 = new Person(‘fgh‘);
        console.log(p1.constructor == Person); //true
        p2 = new p1.constructor(‘bnmn‘);
        console.log(p2.name); //bnmn 
        //两者一致
        console.log(Person);
        console.log(p2.constructor);
    }