深入理解JavaScript中的对象复制(Object Clone)

Object.prototype.clone = function() { var copy = (this instanceof Array) ? [] : {}; for (attr in this) {  if (!obj.hasOwnProperty(attr)) continue;  copy[attr] = (typeof this[i] == "object")?obj[attr].clone():obj[attr]; }  return copy;};a = {k1:1, k2:2, k3:3};b = a.clone();

function clone(obj) {  // Handle the 3 simple types, and null or undefined  if (null == obj || "object" != typeof obj) return obj;  // Handle Date  if (obj instanceof Date) {    var copy = new Date();    copy.setTime(obj.getTime());    return copy;  }  // Handle Array  if (obj instanceof Array) {    var copy = [];    for (var i = 0, var len = obj.length; i < len; ++i) {      copy[i] = clone(obj[i]);    }    return copy;  }  // Handle Object  if (obj instanceof Object) {    var copy = {};    for (var attr in obj) {      if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);    }    return copy;  }  throw new Error("Unable to copy obj! Its type isn't supported.");}