HTML5 Local Storage with Expiration

localStorage.js

AZHU.storage = {
	save : function(key, jsonData, expirationMin){
		if (!Modernizr.localstorage){return false;}
		var expirationMS = expirationMin * 60 * 1000;
		var record = {value: JSON.stringify(jsonData), timestamp: new Date().getTime() + expirationMS}
		localStorage.setItem(key, JSON.stringify(record));
		return jsonData;
	},
	load : function(key){
		if (!Modernizr.localstorage){return false;}
		var record = JSON.parse(localStorage.getItem(key));
		if (!record){return false;}
		// 没有超期返回保存的数据，如果超了返回false
		return (new Date().getTime() < record.timestamp && JSON.parse(record.value));
	}
}

另一个参考
支持localStorage设置过期时间功能的封装代码