User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ru; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 XPCOMViewer/0.9.5 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; ru-RU; rv:1.8.1.1) Gecko/20061204 Firefox/2.0.0.1 I am writing extention for new e-mail messages notification with multi-account support. And i need to harvest all cookies for each account and save them in array - it's not difficult (Using httpChannel.getResponseHeader("Set-Cookie").split("\n");), but when i checking each account i need to dinamicly change cookie header. i use following code: for (var name in this._cookieData) httpChannel.setRequestHeader("Cookie", this._cookieData[name], true); But this code make following: Cookie: name1=value1, name2=value2,... nameN=valueN instead: Cookie: name1=value1; name2=value2;... nameN=valueN source of it i found in following core code: http://lxr.mozilla.org/mozilla/source/netwerk/protocol/http/src/nsHttpHeaderArray.cpp#48 83 // Delimit each value from the others using a comma (per HTTP spec) 84 entry->value.AppendLiteral(", "); I found RFC: HTTP State Management Mechanism - Proposed Standard RFC 2109 This document specifies a way to create a stateful session with HTTP requests and responses. It describes two new headers, Cookie and Set-Cookie, which carry state information between participating origin servers and user agents. The method described here differs from Netscape's Cookie proposal, but it can interoperate with HTTP/1.0 user agents that use Netscape's method. (See the HISTORICAL section.) http://www.w3.org/Protocols/rfc2109/rfc2109 and what i see: Note: For backward compatibility, the separator in the Cookie header is semi-colon (;) everywhere. A server should also accept comma (,) as the separator between cookie-values for future compatibility. Server SHOULD, but 99% of servers backend software use the following (or similar) code to split Cookie header: var cookieHeader = ..... var cookiesArray = cookieHeader..split(";") And as a result for me, servers got cookie header with comma delimiter without error, but software cannot work with cookies. Some mail services set session ID in url, but several (for example: mail.yandex.ru - one of bigger mail service in Russia will mot work without cookies - Why? "That the question, but not to me" (c) W. Shakespeare). So i see two way: change from: 84 entry->value.AppendLiteral(", "); to: 84 entry->value.AppendLiteral("; "); Or (and i think it better than first way) make opportunity for developers ti choise beetwen comma and semi-colon: httpChannel.setRequestHeader("Cookie", this._cookieData[name], true, DELIMITER_TYPE); const DELIMITER_TYPE_SEMI_COLON = 1 (if type blank = semi-colon is default value) const DELIMITER_TYPE_COMMA = 2 For this moment i make trick for fix this bug: var compl_cookies = ""; for (var name in this._cookieData) compl_cookies = compl_cookies + this._cookieData[name] + "; "; httpChannel.setRequestHeader("Cookie", compl_cookies, true); Reproducible: Always Steps to Reproduce: 1. 2. 3.