UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/59.0.3071.29 Safari/537.36

Steps to reproduce the problem:
The XMLHttpRequest() 'onerror' event fires on all kinds of conditions. I am looking for ways to distinguish between states such as:

- net::ERR_INTERNET_DISCONNECTED
- net::ERR_QUIC_PROTOCOL_ERROR
- net::ERR_CONNECTION_TIMED_OUT
- net::ERR_NAME_NOT_RESOLVED
- XMLHttpRequest cannot load https://example.com. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

To reproduce, go to http://testmyinter.net/simpletest.html. This sends xhr requests every 30 seconds, using the params on the page. Open the Console to see error messages

1.  to force ERR_NAME_NOT_RESOLVED, enter http://WontResolve3.14159.com in the top box
2. to force ERR_CONNECTION_TIMED_OUT, enter 'http://123.45.67.89' and 20000 in the second box
3. to force a CORS error, enter a valid host (e.g. http://www.google.com)

What is the expected behavior?
Have the ability to distinguish these cases from Javascript onerror handler

What went wrong?
onerror handler only gets 'error' state, the ProgressEvent (displayed in the Console) doesn't seem to show any further info.

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 59.0.3071.29  Channel: n/a
OS Version: OS X 10.12.4
Flash Version: 

Clearly, Chrome knows how to get this info/these disparate states. Is there any way for my Javascript to do it? Thanks!