bool setcookie ( string name [, string value [, int expire [, string path [, string domain [, int secure]]]]])
path:
If set to '/', the cookie will be available within the entire domain. If set to '/foo/', the cookie will only be available within the /foo/ directory and all sub-directories such as /foo/bar/ of domain. The default value is the current directory that the cookie is being set in.
path:
If set to '/', the cookie will be available within the entire domain. If set to '/foo/', the cookie will only be available within the /foo/ directory and all sub-directories such as /foo/bar/ of domain. The default value is the current directory that the cookie is being set in.
1、在设定cookie的时候加了路径，含路径的cookie是不能随便被清空的。
2、php的cookie传递比较慢，清空后不会马上消失，你再刷新一下看看，也许就可以了。