function pluralizeRus(n, forms) {
return n % 10 == 1 && n % 100 != 11
? forms[0]
: (n % 10 >= 2 && n % 10 <= 4
&& (n % 100 < 10
|| n % 100 >= 20) ? forms[1] : forms[2]);
}
alert('6 Скриншот' + pluralizeRus(6, ['', 'а', 'ов']));