Php backend
The front js
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.Xxx.com easily operate together before and after the end of the multi-domain points in front of, on nginx configuration, can not go anywhere, given nginx
proxy_set_header Cookie $http_cookie;
proxy_cookie_domain
In front of the .xxx..com point seemingly not nginx php or add only back-end operations cookie and no prefix point
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Starting off from js plus point, document.domain not add up, does not add up. After the cookie and the Path operation js also wander around the edge, a plurality of the cookie value generated easily, and is also not a fixed path through document.domain
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Math calculation, let js ajax sent to the back-end synchronization cookie bar