technobulka

var c = 9,  // current, start from length-1
    l = 10, // length
    i;      // index, 0 - prev, 1 - next
c = i?++c%l:~--c%l?c%l:l-1;

technobulka

function numEnd(n,t){return t[n%100>4&&n%100<20?2:'201112'[n%10<5?n%10:5]]}

// test
var a = [1, 2, 5, 10, 20, 21, 22],
    i = 0;

for (i in a) {
    console.log(a[i] + ' котик' + numEnd(a[i], ['', 'а', 'ов']));
}

technobulka

// Cookie object
var cookie = {
    init: function() {
        var cookies = document.cookie.split(/;\s*/),
            cookie = [],
            i = cookies.length;
        
        while (i--) {
            cookie = cookies[i].split('=');
            this[cookie[0]] = cookie[1];

technobulka

function(m,y){return 31-((m==2)<<!(!(y%400^y%100)&!(y%4)))-(m-1)%7%2}