localStorage和sessionStorage使用

localStorage.setItem("key","value");//存数据
localStorage.getItem("key");//取数据
localStorage.removeItem("key");//删除数据
localStorage.clear();?//清空数据

function localStorage_set(key, value , exp) {
    if (typeof exp == "undefined") {
        //默认缓存7天时间
        exp = 1000 * 60 * 60 * 24 * 7;
    }
    var curTime = new Date().getTime();
    localStorage.setItem(key, JSON.stringify({data: value, time: curTime, exp: exp}));
}

function localStorage_get(key) {
    var data = localStorage.getItem(key);
    if(data == null){
        return null;
    }
    var dataObj = JSON.parse(data);
    if (new Date().getTime() - dataObj.time > dataObj.exp) {
        localStorage.removeItem(key);
        return null;
    } else {
        var dataObjDatatoJson = JSON.parse(dataObj.data)
        return dataObjDatatoJson;
    }
}