Code-Fellows reading notes.
//
//
events occur when users click or tap on a link, hover or swipe over an element, type on a keyboard, resize a window, etc.
THE SELECTION OF EVENT TYPES ON PAGE 246 WILL HELP WITH FUNCTION BUILDING
element.oneevent = functionName;
function checkUsername(){
var el = document.}getElementById('username');
el.onblur = checkUsername;
;
element.addEvent =Listener('event', functionName [, Boolean]);
see diagram on page 260
HTML5 vs mutation events vs form events vs keyboard events vs mouse events vs focus & blur events vs user interface events