问题
Firefox is sending my ".domain.tld" cookies when I go to sub.domain.tld.
How can I make sure that the browser only sends cookies of ".sub.domain.tld" and not ".domain.tld"?
回答1:
You cannot. If you set a cookie on .domain.tld it will be sent to domain.tld and all subdomains.
Although this may be unrelated to your problem, take a look at sstatic.net - where the Stack Overflow family of sites host their static resources.
来源：https://stackoverflow.com/questions/1789789/cookies-of-domain-are-sent-to-subdomain-how-to-fix