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

/**
 * 设置缓存数据
 * 默认缓存一个星期
 * @param key
 * @param value
 * @param exp  缓存时间（d天数，h小时，m分钟，s秒【例：7d=7天，7h=7小时，7m=7分钟】）
 */
function lStorage_set(key,value,exp) {
    var timestamp = new Date().getTime();
    if(typeof exp != "undefined"){
        if (endWith(exp,'d')) {
            exp = timestamp + parseInt(exp.replace('d','')) * 1000 * 60 * 60 * 24;
        } else if(endWith(exp,'h')){
            exp = timestamp + parseInt(exp.replace('h', '')) * 1000 * 60 * 60;
        } else if (endWith(exp, 'm')) {
            exp = timestamp + parseInt(exp.replace('m', '')) * 1000 * 60;
        } else if (endWith(exp, 's')) {
            exp = timestamp + parseInt(exp.replace('s', '')) * 1000;
        } else {
            exp = timestamp + exp;
        }
    }else{
        exp = timestamp + (1000 * 60 * 60 * 24 * 7);

    }
    localStorage.setItem(key, JSON.stringify({data: value, exp: exp}));
}

/**
 * 获取缓存数据
 * @param key
 * @returns {null}
 */
function lStorage_get(key) {
    var data = localStorage.getItem(key);
    if(data == null){
        return null;
    }
    var timestamp = new Date().getTime();
    var dataObj = JSON.parse(data);
    if(timestamp < dataObj.exp){
        return dataObj.data;
    }else{
        localStorage.removeItem(key);
        return null;
    }
}

/**
 * 判断data结尾是否是end
 * @param data
 * @param end
 * @returns {boolean}
 */
function endWith(data,end){
    var d = data.length - end.length;
    return (d >= 0 && data.lastIndexOf(end) == d);
}