JavaScript類比的HashMap，請大家多多提意見！

/** * V1.0 * HashMap javascript版 * 2013-09-04  * var map = new $.HashMap();    map.put("age","20");    map.put("name","yk1");    alert(map.get("age"));    alert(map.toString());        map = new $.HashMap({"username":"ycyk_168","password":"123456"});    map.put("age","20");    map.put("name","yk1");    alert(map.get("username"));    alert(map.get("password"));    alert(map.get("age"));    alert(map.get("name"));    alert(map.toString()); * */jQuery.HashMap = function(param) {var _map = typeof(param)=="undefined" ? [{}] : [param];/** * 向HashMap中添加資料 */_map.put =  function(key,value){this[0][key] = value;};/** * 從HashMap中擷取指定的Key的值 */_map.get = function(key){return this[0][key];};/** * HashMap中是否包含指定的Key */_map.containsKey = function(key){return this.get(key) == null ? false : true;};/** * 從HshMap中刪除Key */_map.remove = function(key){delete this[0][key];};/** * 擷取HashMap的大小 */_map.size = function(){var count = 0;for(var item in this[0]){count ++;}return count;};/** * 將HashMap轉換為string的資料 */_map.toString = function(){var str = "{";for(var item in this[0]){str += ""+ item +":"+ this[0][item] +",";}str = $.util.removeEnd(str,",") + "}";return str;};/** * 將HashMap轉換為JSON格式的資料 */_map.toJson = function(){return this[0];};return _map;};