登陆问题，浏览器是如何知道下一次请求网址的？

rm_jwf

输入https://account.xiaomi.com/pass/serviceLogin?回车，居然连续发送了4次请求！如图：

我的疑问是浏览器是访问https://account.xiaomi.com/pass/serviceLogin?后
是如何知道下一次请求网址(https://account.xiaomi.com/pass/ ... p;_dc=1453106363536)的？


另外每次清楚cookie后访问https://account.xiaomi.com/pass/serviceLogin?，第二个请求https://account.xiaomi.com/pass/ ... p;_dc=1453106363536，中的dc=***************会变，这个dc值是浏览器自已自动产生的还是
服务器分配的？如果是分本的话。它是怎么告诉浏览器的？我看了看response全文里没提及dc=


response原文如下：

• Cache-Control:
  no-cache
  
• Cache-Control:
  no-cache
  
• Cache-Control:
  no-cache
  
• Connection:
  keep-alive
  
• Content-Encoding:
  gzip
  
• Content-Type:
  text/html; charset=UTF-8
  
• Date:
  Mon, 18 Jan 2016 08:39:21 GMT
  
• Expires:
  Thu, 01 Dec 1994 16:00:00 GMT
  
• Server:
  Tengine
  
• Set-Cookie:
  cUserId=EXPIRED; domain=.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  JSESSIONID=aaaLvlmzOpXrt9Ff7a2iv; path=/
  
• Set-Cookie:
  deviceId=wb_68a8a6f2-3deb-45c5-ba58-a8a37693af94; domain=account.xiaomi.com; path=/; expires=Sat, 05-Feb-2084 11:53:28 GMT
  
• Set-Cookie:
  userId=EXPIRED; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  userId=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  userId=EXPIRED; domain=.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  userId=EXPIRED; domain=account.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  userId=EXPIRED; domain=.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; domain=.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; domain=account.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  serviceToken=EXPIRED; domain=.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  cUserId=EXPIRED; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  uLocale=zh_CN; domain=.xiaomi.com; path=/; expires=Tue, 02-Feb-2016 08:39:21 GMT
  
• Set-Cookie:
  cUserId=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  cUserId=EXPIRED; domain=account.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  cUserId=EXPIRED; domain=.xiaomi.com; path=/pass/auth; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  passToken=EXPIRED; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  passToken=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  passToken=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  continue=EXPIRED; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  sns_type=EXPIRED; domain=.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  sns_weixin_openId=EXPIRED; domain=.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  sns_weixin_openId=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  etao_qs=EXPIRED; domain=account.xiaomi.com; path=/; expires=Thu, 01-Dec-1994 16:00:00 GMT
  
• Set-Cookie:
  pass_trace=zCzdrInwyxJaQHgLajqLI0ylcUPl3kV28C/MgBLW4JaQYgbyHpfrBauDBL6Zj6Q7pA+cmMLbFUT8WImgbkjHk/sfesaxSSmkUliqdLpsFKFDWfeeguhuK5/QjyuVoTeB; domain=account.xiaomi.com; path=/; expires=Sat, 05-Feb-2084 11:53:28 GMT
  
• Strict-Transport-Security:
  max-age=7
  
• Transfer-Encoding:
  chunked
  
• X-Frame-Options:
  SAMEORIGIN
  
  

helloword

js写的