<script type="text/javascript">
function Hashtable() { 
 this._hashValue= new Object(); 
 this._iCount= 0; 
} 
 
Hashtable.prototype.add = function(strKey, value) { 
 if(typeof (strKey) == "string"){ 
 this._hashValue[strKey]= typeof (value) != "undefined"? value : null; 
 this._iCount++; 
 returntrue; 
 } 
 else 
 throw"hash key not allow null!"; 
} 
 
Hashtable.prototype.get = function (key) { 
 if (typeof (key)== "string" && this._hashValue[key] != typeof('undefined')) { 
 returnthis._hashValue[key]; 
 } 
 if(typeof (key) == "number") 
 returnthis._getCellByIndex(key); 
 else 
 throw"hash value not allow null!"; 
 
 returnnull; 
} 
 
Hashtable.prototype.contain = function(key) { 
 returnthis.get(key) != null; 
} 
 
Hashtable.prototype.findKey = function(iIndex) { 
 if(typeof (iIndex) == "number") 
 returnthis._getCellByIndex(iIndex, false); 
 else 
 throw"find key parameter must be a number!"; 
} 
 
Hashtable.prototype.count = function () { 
 returnthis._iCount; 
} 
 
Hashtable.prototype._getCellByIndex = function(iIndex, bIsGetValue) { 
 vari = 0; 
 if(bIsGetValue == null) bIsGetValue = true; 
 for(var key in this._hashValue) { 
 if(i == iIndex) { 
 returnbIsGetValue ? this._hashValue[key] : key; 
 } 
 i++; 
 } 
 returnnull; 
} 
 
Hashtable.prototype.remove = function(key) { 
 for(var strKey in this._hashValue) { 
 if(key == strKey) 
 { 
 deletethis._hashValue[key]; 
 this._iCount--; 
 } 
 } 
} 
 
Hashtable.prototype.clear = function () { 
 for (var key in this._hashValue) { 
 delete this._hashValue[key]; 
 } 
 this._iCount = 0; 
} 
</script>

StringCollection/ArrayList/Stack/Queue等等都可以借鉴这个思路来对JavaScript 进行扩展。