Sljubura

    var arr = [],
        i = arr.length;

    while (i--) {

        // Do something with array.

    }

Sljubura

    function foo() {
        console.log('global foo');
    }
    function bar() {
        console.log('global bar');
    }
    function hoistMe() {
        console.log(typeof foo); // "function"
        console.log(typeof bar); // "undefined"

Sljubura

    // Calling callback when callback is a method of an object
    var myapp = {};
    myapp.elementHeight = 100;
    myapp.setElementHeight = function (node) {
        node.style.height = this.elementHeight;
    };
    // Where setElementHeight is our callback

    // findNodes() function which call our callback
    var findNodes = function (callback) {

Sljubura

    // Self-defining functions
    var greetings = function () {

        console.log("Hello!");

        greetings = function () {

            console.log("Goodbye!");

        }

Sljubura

    // Clean globals with name-spacing pattern
    // Anti-pattern
    // Pollution with 5 objects added to global.
    function add() {}
    function subtract() {}

    var container = {};
    var data = {};
    data.person = {name: 'John', email: 'smith@gmail.com'};
    data.account = {};

Sljubura

    // Implement private members with closure
    function Person() {
        var name = 'Frank';
        this.getName = function () { // Privileged method, has access to private property.
            return name;
        }
    }
    var user = new Person();

    console.log(user.name); // undefined

Sljubura

    // Module pattern
    APP.utilities.array = (function () {

        // Private properties 
        var array_string = "[object Array]",
            ops = Object.prototype.toString(),

            // Private methods
            inArray = function (haystack, needle) {
                for (var i = 0; i < haystack.length; i = i + 1) {

Sljubura

    // Module pattern that creates constructor function.
    APP.utilities.Array = (function (app, global) {

        // Dependencies
        var uobj = APP.utilities.object,
            ulang = APP.utilities.lang,

        // Private properties
            Constructor;

Sljubura

    function Sandbox() {

        // turning arguments into an array
        var args = Array.prototype.slice.call(arguments),
            // last argument is the callback
            callback = args.pop(),
            // modules can be passed as an array or as individual parameters
            modules = (args[0] && typeof args[0] === "string") ? args : args[0],
            i;

Sljubura

// Always use lates version

// Not all selectors are equaly fast
// Fastest to slowest selectors.
$('#selector-by-id');
$('div', 'input');
$('.class-selectors');
// And the slowest are pseudo selectors
$(':visible, :hidden, [attribute=value]');