Склонение числительных в javascript

declOfNum.js

function declOfNum(number, titles) {  
    var cases = [2, 0, 1, 1, 1, 2];  
    return titles[ (number%100>4 && number%100<20)? 2 : cases[(number%10<5)?number%10:5] ];  
}

//usage:
var num = 15;
declOfNum(num, ['товар', 'товара', 'товаров']);