【 tulaoshi.com - Web开发 】
                             
                            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"));