LocalStorage cookie emulation for using in iframes for example.

cookie.js

var getCookie = function(name) {
  var ls = window.localStorage,
	  data = ls.getItem(name);

	if(data) {
		data = JSON.parse(data);
		if(new Date(data.expires).getTime() > Date.now() ) {
			return data.value;
		} else {
			ls.removeItem(name);
		}
	}
	return undefined;
};

var setCookie = function(name, value, expires) {
	var ls = window.localStorage;
	if(value === null) {
		ls.removeItem(name);
	} else {
		ls.setItem(name, JSON.stringify({value: value, expires: expires}));
	}
};