document.cookie is empty, however there are some cookies on this site

document.cookie is empty, however there are some cookies on this site

I try开发者_高级运维 to clean cookie from http://ya.ru (firebug show some cookies on this site) but document.cookie is empty

Why?

The cookies being set on ya.ru are invalid. From the headers:

Set-Cookie:S=; path=/; expires=Thu, 12-Apr-2001 18:01:31 GMT
S=; domain=.ya.ru; path=/; expires=Thu, 12-Apr-2001 18:01:31 GMT

That means that the cookie S is being set to blank (and once on a potentially invalid domain .ya.ru)

and from kiss.ya.ru:

Cookie:yandexuid=740707471300761151; fuid01=4d880a3f046a3adb.XAGDFwCcblJ88BiI0-dizIwYqqeFGNCvuzmuswZQjSzBOiQsoOPEvCh0rUsbgtkecV63gqRK6ya5qdTjR-LlwdBAsop6Em9vXP6vlBLZgLZQolx7uVPD4Qw_PPWCapoE
yandexuid=740707471300761151; fuid01=4d880a3f046a3adb.XAGDFwCcblJ88BiI0-dizIwYqqeFGNCvuzmuswZQjSzBOiQsoOPEvCh0rUsbgtkecV63gqRK6ya5qdTjR-LlwdBAsop6Em9vXP6vlBLZgLZQolx7uVPD4Qw_PPWCapoE

Since the site is running on ya.ru, you can't read the kiss.ya.ru cookies due to security issues.

Probably a security thing. If the Javascript has been load from a host or path different than the one set for the cookie, the cookie's invisible.