Null vs Undefined

Learn about the difference between null and undefined in JavaScript. Code: ? http://codepen.io/beaucarnes/pen/ygLwod?editors=0012 Other resources on topic: ? http://www.jstips.co/en/differences-between-undefined-and-null/ ? https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/null#Difference_between_null_and_undefined JS Nuggets: Brisk JavaScript training and tips