JS 怎么写 哈希列表

window.Hashtable=function()
{
        this.Items={};
        this.Count=function()
        {
                var count=0;
                for(var i in this.Items)        count++;
                return count;
        };        //长度

        this.Add=function(key,value)
        {
                if(this.ContainsKey(key))        this.Error("Hashtable已经存在"+key+"键");
                this.Items[key]=value;
        }
        this.SetValue=function(key,value)
        {
                if(this.ContainsKey(key))        this.Items[key]=value;
                else this.Error("Hashtable不存在"+key+"键");
        }
        this.RemoveAll=function(){this.Items={};}
        this.Remove=function(key){delete this.Items[key];}
        this.GetValue=function(key)
        {
                if(this.ContainsKey(key))        return this.Items[key];
                this.Error("Hashtable不存在"+key+"键");
        }
        this.ContainsKey=function(key){return this.Items.hasOwnProperty(key);}
        this.ContainsValue=function(value)
        {
                for(var i in Items)        if(this.Items[ i ]==value)        return true;
                return false;
        }
        this.Keys=function()
        {
                var resultArr=[];
                for(var i in this.Items)        resultArr.push(i.toString());
                return resultArr;
        }
        this.Values=function()
        {
                var resultArr=[];
                for(var i in this.Items)        resultArr.push(Items[ i ]);
                return resultArr;
        }
        this.IsEmpty=function(){return this.Count()==0;}
        this.toArray=function()
        {
                var resultArr=[];
                for(var i in this.Items)        resultArr.push({Key:i,Value:this.Items[ i ]});
                return resultArr;
        }
        this.Error=function(errorMsg)
        {
                CXP.Throw(errorMsg);
        }
}