only hosts within the specified domain can set a cookie for a domain and domains must have at least two (2) or three (3) periods in them to prevent domains of the form: .com, .edu, and va.us. any domain that fails within one of the seven special top level domains listed below only require two periods. any other domain requires at least three. the seven special top level domains are: com, edu, net, org, gov, mil, and int.
看出来了吧，真他娘的草蛋！除了com, edu, net, org, gov, mil, and int这几个后缀的域名可以设置二级作用域，其他的域名至少三级才可以，也就是说想通过设置作用域为b.cn来实现a.b.cn和c.b.cn下的 cookie共享用php是不行的，php只能实现作用域b.a.cn下的d.b.a.cn和e.b.a.cn间的cookie共享，希望大家注意，再遇到此类问题，别浪费时间拼命的测试了……