是的，实际上chrome是按照w3c标准来执行的，你可以看这里的原文描述， http://www.w3.org/TR/XMLHttpRequest/#...

我把它摘录出来

Terminate these steps if header is a case-insensitive match for one of the following headers:

Accept-Charset
Accept-Encoding
Connection
Content-Length
Cookie
Cookie2
Content-Transfer-Encoding
Date
Expect
Host
Keep-Alive
Referer
TE
Trailer
Transfer-Encoding
Upgrade
User-Agent
Via

也就是说，当你的header匹配以上字符时，这一步骤将被终止