温故知新[1]（9.1-9.5）

1.字符串转化成数组：split---[分离]

var s = 'Hello world';
s.split();
>>>["Hello world"]

- slice()可用于复制一个字符串或数组---[切片]

var s = 'Hello world';
s.slice();
>>>"Hello world"

var arr = [1,2,3];
arr.slice();
>>>(3) [1, 2, 3]

2.split()方法细节

var s = 'y';
s.split('y');
>>>(2) ["", ""]

3.实例属性无法修改原型对象中的属性

function Person(){}
Person.prototype.name = 'Gerg';
var person1 = new Person();
person1.name;
>>>"Gerg"

Person.prototype.name = 'asan';
person1.name;
>>>"asan"

person1.prototype;
>>>undefined

4.如何仅获取原型对象中的属性？

function Person(){}
Person.prototype.name = 'Gerg';
Person.prototype.age = 21;
Person.prototype.job = 'Student';
Person.prototype.sayName = function(){
    console.log(this.name);
};
var person1 = new Person();
person1.city = 'Shanghai';
function getPurePrototypeProperty(o){
    for(var i in o){
        if(!o.hasOwnProperty(i) && (i in o)){
            console.log(i);
        }
    }
}
getPurePrototypeProperty(person1);