JAVASCRIPT HashTable

function Hashtable（）
{
    this._hash        = new Object（）;
    this.add        = function（key,value）{
                        if（typeof（key）！="undefined"）{
                            if（this.contains（key）==false）{
                                this._hash[key]=typeof（value）=="undefined"？null:value;
                                return true;
                            } else {
                                return false;
                            }
                        } else {
                            return false;
                        }
                    }
    this.remove        = function（key）{delete this._hash[key];}
    this.count        = function（）{var i=0;for（var k in this._hash）{i++;} return i;}
    this.items        = function（key）{return this._hash[key];}
    this.contains    = function（key）{ return typeof（this._hash[key]）！="undefined";}
    this.clear        = function（）{for（var k in this._hash）{delete this._hash[k];}}

}

var a = new Hashtable（）;

a.add（"aa"）;
a.add（"bb",2342）;
a.add（"bb",2342）;

a.remove（"aa"）;

alert（a.count（））;

alert（a.contains（"bb"））;

alert（a.contains（"aa"））;

alert（a.items（"bb"））;