//第一個參數是被克隆的對象，第二個參數是需要克隆的屬性列表
function cloneOwn() {
  var obj = arguments[0];
  if (typeof obj === 'undefined' || obj === null)
      return {};
  if (typeof obj !== 'object')
      return obj;
  //第二個參數是屬性名稱列表，就采用該列表進行刷選
  //否則就克隆所有屬性
  var attrs = arguments[1];
  var enable_spec_attr = true;
  if (!(attrs instanceof Array)) {
      //console.log(attrs);
      attrs = obj;
      enable_spec_attr = false;
  }
  var result = {};
  var i;
  for (i in attrs) {
      attr = enable_spec_attr? attrs[i]: i;
      //console.log(attr);
      if (obj.hasOwnProperty(attr)) {
          if (obj[attr] instanceof Array) {
              result[attr] = cloneArray(obj[attr]);
          }
          else if (typeof obj[attr] === 'object') {
              result[attr] = cloneOwn(obj[attr]);
          } else {
              result[attr] = obj[attr];
          }
      }
  }
  return result;
}

//克隆數組
function cloneArray(array) {
  if (typeof array === 'undefined' || array === null)
    return [];

  if (!(array instanceof Array))
    return [];

  result = [];

  var i;
  for(i in array) {
    if (typeof array[i] !== 'object') {
      result[i] = array[i];
      continue;
    }

    //clone object
    result[i] = cloneOwn(array[i]);
  }

  return result;
}

var a = {
    name:'frank',
    age:20
};
var b= cloneOwn(a);

var a = {
    name:'frank',
    age:20,
    address:'any where'
};
var b = cloneOwne(a, ['name', 'age']);

var a = {
    name: 'kxh',
    age: 20,
    books: ['hai','ho','ali'],
    likes: [
        {wname: 'kaili', wage: 81, fav: "aaaaa"},
        {wname: 'seli', wage: 82, fav: "bbb"},
        {wname: 'ailun', wage: 83, fav: "ccc"},]
};
var b = cloneOwne(a);

var a = [
   {
      name:'frank',
      age:20
    },
    {
       name:'leon',
       age:30
     }
];
var b = cloneArray(a);