I'm seeing a delay between AJAX head requests and the header data being available to javascript. The delay is 1-2 minutes, I'm seeing it on Windows 7 IE 11.0.9600.17358 and Windows 8 in the latest version of IE.
Here's a jsfiddle that illustrates the problem:
http://jsfiddle.net/rj8foa8k/20/
In chrome and firefox the three times printed by the jsfiddle (initial load, request made at, and update at) are the same. In IE there is a 2 minute delay between "request made at" and "update at".
I've inspected the packets with fiddler and tcpview, and it appears that IE makes the request instantly, the server responds instantly, but the data is not available to javascript until the connection is closed (keep-alive expires?). No data are sent
on the connection after the initial headers are transmitted.
It doesn't seem to be a problem on all servers, but it always breaks with http://services.swpc.noaa.gov on IE. Any insight into what the problem is, potential workarounds, etc. is greatly appreciated.