This article contains the list of limitation which cookies do have. One of them is the limitation of domain it limited to one domain only. And only 20 cookies are allowed per domain. That really means cookies can only be read from the page of its own domain. Other limitation of the cookies is the path. It can only be used if you know the particular path.
` if the cookies expiration time is not set then it will stay only for that time up to which browser session reside. If cookies cross the expiry date then it will get removed automatically