HTML5 localStorage with expire

html5.localstorage.ex.js

var localStorageEx = {
	get: function (key) {
		var value = localStorage[key];
		if (value != null) {
			var model = JSON.parse(value);
			if (model.payload != null && model.expiry != null) {
				var now = new Date();
				if (now > Date.parse(model.expiry)) {
					localStorage.removeItem(key);
					return null;
				}
			}
			return JSON.parse(value).payload;
		}
		return null;
	},
	set: function (key, value, expirySeconds) {
		var expiryDate = new Date();
		expiryDate.setSeconds(expiryDate.getSeconds() + expirySeconds);
		localStorage[key] = JSON.stringify({
			payload: value,
			expiry: expiryDate
		});
	}
};