function Map() {   
    /** 存放鍵的陣列(遍歷用到) */  
    this.keys = new Array();   
    /** 存放資料 */  
    this.data = new Object();   
    /**  
     * 放入一個鍵值對  
     * @param {String} key  
     * @param {Object} value  
     */  
    this.put = function(key, value) {   
        if(this.data[key] == null){   
            
 
this.keys.push(key);   
        }   
        this.data[key] = value;   
    };   
    /**  
     * 獲取某鍵對應的值  
     * @param {String} key  
     * @return {Object} value  
     */  
    this.get = function(key) {   
        return this.data[key];   
    };   
    /**  
     * 刪除一個鍵值對  
     * @param {String} key  
     
 
*/  
    this.remove = function(key) {   
        this.keys.remove(key);   
        this.data[key] = null;   
    };   
    /**  
     * 遍歷Map,執行處理函式  
     *   
     * @param {Function} 回撥函式 function(key,value,index){..}  
     */  
    this.each = function(fn){   
        if(typeof fn != 'function'){   
            
 
return;   
        }   
        var len = this.keys.length;   
        for(var i=0;i<len;i++){   
            var k = this.keys[i];   
            fn(k,this.data[k],i);   
        }   
    };   
    /**  
     * 獲取鍵值陣列(類似Java的entrySet())  
     * @return 鍵值物件{key,value}的陣列  
     */  
    this.entrys = function() {   
        var len = this.keys.length;   
        var entrys = new Array(len);   
        for (var i = 0; i < len; i++) {   
            entrys[i] = {   
                key : this.keys[i],   
                value : this.data[i]   
            };   
        }   
        return entrys;   
    };   
    /**  
     * 判斷Map是否為空  
     */  
    this.isEmpty = function() {   
        return this.keys.length == 0;   
    };   
    /**  
     * 獲取鍵值對數量  
     */  
    this.size = function(){   
        return this.keys.length;   
    };   
    /**  
     * 重寫toString   
     */  
    this.toString = function(){   
        var s = "{";   
        for(var i=0;i<this.keys.length;i++,s+=','){   
            var k = this.keys[i];   
            s += k+"="+this.data[k];   
        }   
        s+="}";   
        return s;   
    };   
}   

//測試效果
function testMap(){   
    var m = new Map();   
    m.put('key1','Comtop');   
    m.put('key2','測試2');   
    m.put('key3','測試3');   
    alert("init:"+m);   
       
    m.put('key1','測試測試');   
    alert("set key1:"+m);   
       
    m.remove("key2");   
    alert("remove key2: "+m);   
       
    var s ="";   
    m.each(function(key,value,index){   
        s += index+":"+ key+"="+value+"/n";   
    });   
    alert(s);   
}