var Map = function(){  // 構造entry實體  var Entry = function(key, value){    this.key = key;    this.value = value;  }  this.entries = new Array();  // 構造put方法在數組中放入一個Entry  this.put = function(key, value){    // 數組中已存在就不放入    for (var i = 0; i < this.size(); i++) {      if (this.entries[i].key === key) {        return false;      }    }    this.entries.push(new Entry(key, value));  };  // 模擬get方法  this.get = function(key){    for (var i = 0; i < this.size(); i++) {      if (this.entries[i].key === key) {        return this.entries[i].value;      }    }    return null;  };  // 查找下標值  this.indexOf = function(key){    var index = -1;    for (var i = 0; i < this.size(); i++) {      if (this.entries[i].key === key) {        index = i;        break;      }    }    return index;  }  // 刪除一個元素  this.remove = function(key){    var index = this.indexOf(key);    if (index != -1) {      this.entries.splice(index, 1);    }  }  // 取得map長度  this.size = function(){    return this.entries.length;  };  // 重新設置鍵值對  this.setValue = function(key, value){    var index = this.indexOf(key);    if (index != -1) {      this.entries[i].value = value;    };  };  // 是否為空map  this.isEmpty = function(){    return this.size() <= 0;  };  //清空map ;  this.clear = function(){    this.entries = [];  };  // 得到entry實體  this.getEntry = function(index){    if (index >= 0 && index < this.size()) {      return this.entries[index];    }    return null;  }  this.toString = function(){    var str = "[";    for (var i = 0; i < this.size(); i++) {      str += this.getEntry(i).key + "=" + this.getEntry(i).value + ",";    }    // 去除最后一個","    str = str.substring(0, str.length - 1);    str += "]";    return str;  };}