Objects are key value pairs, values can be any type, passed by reference, undefined for properties that are undefined

A function inside an object is called a method

Polymorphism: same name but different behavior; different method

Keyword this is set to the object or function we are calling

Instanceof: checks prototype

Wrapping JavaScript in function block creates a closure and avoids potential name clashes between modules and libraries

JavaScript is loosly typed, define without specifying type

No destructors in JavaScript

Graceful degradation: providing alternate version of functionality to ensure the product is usable, you start with modern browsers

Progressive enhancement: establish basic user experience and build in more advanced functionality

Optimize assets/resources: fewer HTTP requests, use Content Delivery Network, add an Expires header, put CSS on top, scripts on bottom, JavaScript and CSS external, minify JavaScript, avoid redirects, remove duplicate scripts, host assets on a different domain

Decrease page load: minimize images, combine JavaScript files, combine CSS files

Standards: more stable web, reduce development and maintenance time, backward capabilities, increase search engine success, common knowledge

CORS: cross-origin resource sharing, allows restricted resources to be requested from another domain

Undefined: value of variable was undefined, type is undefined

Null: empty or non-existant value, primative value, null == undefined

Object equality: primitives by value, objects compared by reference

'false' is true because its a string greater than 0

Currying: partial invocation of a function

Window is a global object that holds global variables, functions, and location

Document is under window: window.document === document

Reflow: change the size or position of an element and everything else moves

Repaint: change the look without changing the size or shape

Use semantic tags for SEO, accessibility

Use anonymous functions because no name is needed or only used once