使用jquery插件操作哈希表Hashtable的应用

jQuery.Hashtable = function() {
    this.items = new Array();
    this.itemsCount = 0;
    this.add = function(key, value) {
        if (!this.containsKey(key)) {
            this.items[key] = value;
            this.itemsCount  ;
        }
        else
            throw "key '"   key   "' allready exists."
    }
    this.get = function(key) {
        if (this.containsKey(key))
            return this.items[key];
        else
            return null;
    }

    this.remove = function(key) {
        if (this.containsKey(key)) {
            delete this.items[key];
            this.itemsCount--;
        }
        else
            throw "key '"   key   "' does not exists."
    }
    this.containsKey = function(key) {
        return typeof (this.items[key]) != "undefined";
    }
    this.containsValue = function containsValue(value) {
        for (var item in this.items) {
            if (this.items[item] == value)
                return true;
        }
        return false;
    }
    this.contains = function(keyOrValue) {
        return this.containsKey(keyOrValue) || this.containsValue(keyOrValue);
    }
    this.clear = function() {
        this.items = new Array();
        itemsCount = 0;
    }
    this.size = function() {
        return this.itemsCount;
    }
    this.isEmpty = function() {
        return this.size() == 0;
    }
};

var hashtable = new jQuery.Hashtable();
$(function() {
    $('#btnAdd').click(function() {
        hashtable.add($('#txtAddKey').val(), $('#txtAddValue').val());
    });
    $('#btnGet').click(function() {
        alert(hashtable.get($('#txtGetKey').val()))
    });
})