这是与浏览器设置有关, 过去我们的网站是http, 设置了缓存cookies使得网友每次访问都快速;现在使用了https,安全考虑会在缺省状态下每次清理缓存---当你登陆出去后; 但是如果保留登陆状态, 即便关机, 浏览器如果设置保留依旧会保留缓存:你这样检查---Google Chrome
Click the menu icon on the browser toolbar.
Select Settings.
Click the Show advanced settings... link.
Click Content Settings... ...
In the "Cookies" section of the dialog that appears, make sure Allow local data to be set is selected to allow both first-party and third-party cookies.
Click Done.