http://stackoverflow.com/questions/42292994/how-to-erase-drawing-in-fabric-js
http://stackoverflow.com/questions/42296241/fabricjs-group-itext-and-rectangle-within-rectangle-boundaries
Assign object identifier to some objects in fabric.js and save it as json
jQuery 2.2.0, HTML, CSS, JavaScript
jQuery 1.11.0, HTML, CSS, JavaScript