Advantages of preprocessor? sass, stylus, less.

Difference between callback and closure in js?

Example of callback? ...how

What about events? addEventListeners? e.target?

Flex-box. CSS. JS.

// What does this code return? var Foo = function (a) { this.bar = () => { return a; } var baz = function () { return a; }; }; Foo.prototype = { biz: () => { return this.bar(); } }; var f = new Foo(7); f.bar(); //=> f.baz(); //=> f.biz(); //=>

// Given var endorsements = [ { skill: 'css', user: 'Bill' }, { skill: 'javascript', user: 'Chad' }, { skill: 'javascript', user: 'Bill' }, { skill: 'css', user: 'Sue' }, { skill: 'javascript', user: 'Sue' }, { skill: 'html', user: 'Sue' } ]; getSkills = (endorsements) => { // Result // [ // { skill: 'javascript', user: ['Chad', 'Bill', 'Sue'], count: 3 }, // { skill: 'css', user: ['Sue', 'Bill'], count: 2 }, // { skill: 'html', user: ['Sue'], count: 1 } // ]; } see this image: http://i.imgur.com/UIeB3n4.png

// How can I know which radio was clicked or selected? <h2>Monstrous Government Form</h2> <form id="myForm" name="myForm"> <fieldset> <legend>Do you live in an:</legend> <p><input type="radio" name="home" value="apartment" id="apartment" /> <label for="apartment">Apartment</label></p> <p><input type="radio" name="home" value="house" id="house" /> <label for="house">House</label></p> <p><input type="radio" name="home" value="mobile" id="mobile" /> <label for="mobile">Mobile Home/Trailer</label></p> <p><input type="radio" name="home" value="coop" id="coop" /> <label for="coop">Co-op</label></p> <p><input type="radio" name="home" value="none" id="none" /> <label for="none">None</label></p> </fieldset> <fieldset> <legend>Your income is:</legend> <p><input type="radio" name="inc" value="0-50K" id="0-50K" /> <label for="0-50K">$0-50,000 USD</label></p> <p><input type="radio" name="inc" value="50-100K" id="50-100K" /> <label for="50-100K">$50,000-100,000 USD</label></p> <p><input type="radio" name="inc" value="100K+" id="100K+" /> <label for="100K+">$100,000+ USD</label></p> </fieldset> <fieldset> <legend>Your status is:</legend> <p><input type="radio" name="status" value="single" id="single" /> <label for="single">single</label></p> <p><input type="radio" name="status" value="married" id="married" /> <label for="married">married</label></p> <p><input type="radio" name="status" value="partner" id="partner" /> <label for="partner">domestic partner</label></p> </fieldset> <p>This form goes on with another 97 questions....</p> <input type="submit" value="Submit" /> </form>