var Class = (function(){ // private valiable var privates = { names: {} }; var _class = function(){ this.id = 'mohwa'; this.key = String(new Date().getTime()); return this; } _class.fn = _class.prototype = { getName: function(){ return privates['names'[this.key]]; }, setName: function(name){ privates['names'[this.key]] = name; return this; } } return _class; })(); alert(new Class().setName('전성균').getName()); alert(new Class().names);