没有object对象的转化 @param json @return

* Make a map and return a function for checking if a key * is in that map.

* Displays an alert. * @param {String} str String to display.

* Quick object check - this is primarily used to tell * Objects from primitive values when we know the value * is a JSON-compliant type.

* Extend a prototyped class by new members * @param {Object} parent * @param {Object} members

* Check for object * @param {Object} obj

* Strict object type check. Only returns true * for plain JavaScript objects.