Deep Clone a JavaScript Object

object+deepClone.js

function deepClone(obj) {
  var copy;
  var i;
  var len;

  if (!obj || typeof obj !== 'object') {
      return obj;
  }

  if (obj instanceof Array) {
      copy = [];
      for (i = 0, len = obj.length; i < len; i++) {
          copy[i] = deepClone(obj[i]);
      }
      return copy;
  }

  if (obj instanceof Object) {
      copy = Object.create(obj.constructor.prototype);
      for (var prop in obj) {
          if (obj.hasOwnProperty(prop)) {
              copy[prop] = deepClone(obj[prop]);
          }
      }
  }

  return copy;
}