Ajax 请求有时会在 Chrome 中长时间停滞。
我终于成功地复制了它并保存了所有必要的相关数据，如果有人可以帮助我的话，可以在这里发布。
The timeline from Chrome Dev Tool shows the request stalled for 42.62s as the following screen capture shows:
并在chrome://net-internals/#events（有关事件日志，请转到末尾）页面我发现最多的时间是由两个事件花费的：
两者都得到ERR_CONNECTION_RESET.
我认为该错误是请求停滞这么长时间的原因。
任何人都可以解释这些错误吗？
以下是请求的事件日志，我还将完整事件导出为 json，您可以从中获取here https://gist.githubusercontent.com/wayou/39772215d075c80d643a/raw/9c91463f22016d20c90de19e77ae3e4f302e0769/gistfile1.txt然后在Chrome中恢复chrome://net-internals/#events页。请注意，请求 url 是内部的，因此可能无法从公共网络访问：
193486: URL_REQUEST
http://qa.tieba.baidu.com/release/getReleaseHistory?projectId=fum1.0.593
Start Time: 2015-01-02 17:51:05.323
t= 1 [st= 0] +REQUEST_ALIVE [dt=42741]
t= 1 [st= 0] URL_REQUEST_DELEGATE [dt=0]
t= 1 [st= 0] +URL_REQUEST_START_JOB [dt=42740]
--> load_flags = 339804160 (BYPASS_DATA_REDUCTION_PROXY | MAYBE_USER_GESTURE | REPORT_RAW_HEADERS | VERIFY_EV_CERT)
--> method = "GET"
--> priority = "LOW"
--> url = "http://qa.tieba.baidu.com/release/getReleaseHistory?projectId=fum1.0.593"
t= 2 [st= 1] URL_REQUEST_DELEGATE [dt=0]
t= 2 [st= 1] HTTP_CACHE_GET_BACKEND [dt=0]
t= 2 [st= 1] HTTP_CACHE_OPEN_ENTRY [dt=0]
t= 2 [st= 1] HTTP_CACHE_ADD_TO_ENTRY [dt=0]
t= 2 [st= 1] HTTP_CACHE_READ_INFO [dt=0]
t= 2 [st= 1] URL_REQUEST_DELEGATE [dt=0]
t= 2 [st= 1] +HTTP_STREAM_REQUEST [dt=2]
t= 4 [st= 3] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193488 (HTTP_STREAM_JOB)
t= 4 [st= 3] -HTTP_STREAM_REQUEST
t= 4 [st= 3] +HTTP_TRANSACTION_SEND_REQUEST [dt=0]
t= 4 [st= 3] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t= 4 [st= 3] -HTTP_TRANSACTION_SEND_REQUEST
t= 4 [st= 3] +HTTP_TRANSACTION_READ_HEADERS [dt=21301]
t= 4 [st= 3] HTTP_STREAM_PARSER_READ_HEADERS [dt=21301]
--> net_error = -101 (ERR_CONNECTION_RESET)
t=21305 [st=21304] HTTP_TRANSACTION_RESTART_AFTER_ERROR
--> net_error = -101 (ERR_CONNECTION_RESET)
t=21305 [st=21304] -HTTP_TRANSACTION_READ_HEADERS
t=21305 [st=21304] +HTTP_STREAM_REQUEST [dt=3]
t=21307 [st=21306] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193494 (HTTP_STREAM_JOB)
t=21308 [st=21307] -HTTP_STREAM_REQUEST
t=21308 [st=21307] +HTTP_TRANSACTION_SEND_REQUEST [dt=3]
t=21308 [st=21307] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t=21311 [st=21310] -HTTP_TRANSACTION_SEND_REQUEST
t=21311 [st=21310] +HTTP_TRANSACTION_READ_HEADERS [dt=21304]
t=21311 [st=21310] HTTP_STREAM_PARSER_READ_HEADERS [dt=21304]
--> net_error = -101 (ERR_CONNECTION_RESET)
t=42615 [st=42614] HTTP_TRANSACTION_RESTART_AFTER_ERROR
--> net_error = -101 (ERR_CONNECTION_RESET)
t=42615 [st=42614] -HTTP_TRANSACTION_READ_HEADERS
t=42615 [st=42614] +HTTP_STREAM_REQUEST [dt=12]
t=42627 [st=42626] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193498 (HTTP_STREAM_JOB)
t=42627 [st=42626] -HTTP_STREAM_REQUEST
t=42627 [st=42626] +HTTP_TRANSACTION_SEND_REQUEST [dt=2]
t=42627 [st=42626] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t=42629 [st=42628] -HTTP_TRANSACTION_SEND_REQUEST
t=42629 [st=42628] +HTTP_TRANSACTION_READ_HEADERS [dt=112]
t=42629 [st=42628] HTTP_STREAM_PARSER_READ_HEADERS [dt=112]
t=42741 [st=42740] HTTP_TRANSACTION_READ_RESPONSE_HEADERS
--> HTTP/1.1 200 OK
Date: Fri, 02 Jan 2015 09:51:48 GMT
Content-Type: application/json; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: no-cache
tracecode: 31079600320335034634010217
tracecode: 31079600320537995786010217
Server: Apache
t=42741 [st=42740] -HTTP_TRANSACTION_READ_HEADERS
t=42741 [st=42740] HTTP_CACHE_WRITE_INFO [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_INFO [dt=0]
t=42741 [st=42740] URL_REQUEST_DELEGATE [dt=0]
t=42741 [st=42740] -URL_REQUEST_START_JOB
t=42741 [st=42740] URL_REQUEST_DELEGATE [dt=0]
t=42741 [st=42740] HTTP_TRANSACTION_READ_BODY [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42741 [st=42740] HTTP_TRANSACTION_READ_BODY [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42742 [st=42741] -REQUEST_ALIVE编辑：相关问题 问题 447463：Chrome 网络：过时套接字上的 RST 消息之前的长时间延迟会导致页面加载缓慢。 https://code.google.com/p/chromium/issues/detail?id=447463
我曾经遇到过类似的问题。问题的原因是每个浏览器对服务器的最大 TCP 连接数都有限制。对于 Chrome，限制为 6。当您使用代理服务器时，这个问题更加突出，因为所有请求都经过同一台服务器（代理服务器）。
Chrome 不允许您更改此限制。事实上不应该。如果您想了解更多有关此限制存在的原因以及其他浏览器的限制是什么，您可以阅读本文 http://www.stevesouders.com/blog/2008/03/20/roundup-on-parallel-connections/.
此限制很少成为问题的原因是，对同一主机的多个 HTTP 请求大多是连续发送的，而不是并行发送的，最好是通过同一个 TCP 连接发送。
如果您经常出现此问题，那么原因可能是：
服务器不支持持久 TCP 连接：如果问题仅在访问特定服务器时出现，原因可能是 Chrome 在并行连接上获取多个资源（如图像、CSS 文件等）。由于在您的情况下，服务器位于您的本地网络上，因此您可能需要要求服务器管理员添加对持久 TCP 连接的支持。
打开多个持久连接：如果您在代理服务器后面工作，那么同时下载多个文件或打开保持 TCP 连接打开的站点可能是问题的原因。要摆脱它，您所能做的就是不要同时下载许多文件（或如果需要，请在不同的浏览器中下载）。
PS:错误网络错误 = -101 (ERR_CONNECTION_RESET)不是由于无效标头，而是由于超时，等待之前与服务器的某些连接关闭。