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));