store history and local storage ex

storeHistory.js

// store the canvas image and push to local storage

var storeHistory = function () {
	img = canvas.toDataURL("image/png");
	history.pushState({ imageData: img }, "", window.location.href);
	if (window.localStorage) { localStorage.curImg = img; }
};


//retrieve local storage
if (window.localStorage) { 
	var img = new Image();
	$(img).load(function () {
	       canvas.getContext("2d").drawImage(img, 0, 0);
	});
	if (localStorage.curImg) {
		img.src = localStorage.curImg;		
	}
}

//do history moves
var undo = function () {
	window.history.back();
};

var redo = function () {
	window.history.forward();
};