<script type=text/javascript charset=utf-8>
                function Map(){ 

                    var obj = {} ;// put
                    this.put = function(key , value){
                            obj[key] = value ;
                    }

                    // size
                    this.size = function(){
                            var count = 0 ;
                            for(var attr in obj){
                                count++;
                            }
                            return count ;
                    }

                    // get
                    this.get = function(key){
                        if(obj[key] || obj[key] === 0 || obj[key] === false){
                            return obj[key];
                        } else {
                            return null;
                        }
                    }

                    //remove
                    this.remove = function(key){
                        if(obj[key] || obj[key] === 0 || obj[key] === false){
                            delete obj[key];
                        }
                    }

                    // eachMap
                    this.eachMap = function(fn){
                            for(var attr in obj){
                                fn(attr, obj[attr]);
                            }
                    }

                }

　　　　　　　　  //对map的使用
                var m = new  Map();
                m.put('01' , 'abc');
                m.put('02' , false) ;
                m.put('03' , true);
                m.put('04' , new Date());

                //alert(m.size());

                //alert(m.get('02'));
                //m.remove('03');
                //alert(m.get('03'));

                m.eachMap(function(key , value){
                     alert(key +" ："+ value);
                });

        </script>