jsfiddle demonstrating IE11 difference talking to nginx vs google

[Maxim Dounin]

Hello!

On Wed, Apr 29, 2015 at 01:13:37AM +1000, jb wrote:

> See, or please try:
> http://jsfiddle.net/qe44nbwh/
> 
> If you see what I see in my IE11, when I press Start Test, and the target
> is nginx.org, the duration for each request goes slow/normal/slow/normal
> 
> But when I change nginx.org to google.com, the timing is
> normal/normal/normal ...
> 
> This only happens with IE11, other browsers behave normally
> (they all do normal/normal/normal timings)
> 
> Why would IE11 be sensitive to an nginx server, and not to google ?
> What is nginx doing that google is not doing...

It looks like a combination of the following factors:

- for some reason IE11 closes connections after JS requests to 
  nginx.org in your test;

- when IE11 have to open a connection, it opens 2 of them.

As a result, every second request request uses pre-cached connection 
established previously, and it is fast.  Others have to wait while 
a connection is established.

No idea why IE closes connections, but it doesn't happen on normal 
use.  May be some bug, or heuristics, or a security measure (as 
the test triggers CORS errors).

-- 
Maxim Dounin
http://nginx.org/