js用法2

1，网站cookie

document.cookie

2， Web Storage相当于cookie，当存储量大于cookie

localStorage  存储格式都是字符串
有效期，清空缓存前，永远存在
作用域，限定在文档源级别
例
赋值
localStorage.a = 1；//注意存储的值为'1'
localStorage['a'] = 1；
删除
localStorage.removeItem('a');//清除a的值
localStorage.clear(); // 一无所有了所有数据都会干掉
取值
var a1 = localStorage['a'];//获取a的值
var a2 = localStorage.a;//获取a的值
var a3 = localStorage.getItem('a');//获取a的值
遍历
var  local_history = localStorage;
for(var tmp in local_history){
    console.log(tmp);
    console.log(local_history[tmp]);
//若value是url地址，则需要解密  decodeURI(local_history[tmp])
}