Hello,

We've been having a problem with IE9 dying during the load process. I can see the request, see the response with the script content, but the script content is empty (at least IE's dev tools shows it to be empty). This seems to kill the loader as no more requests are made and the app never starts because it's waiting for all of the scripts to be loaded. There are no errors reported in the console, windows event logs, or anywhere as far as I can tell. Even more frustrating, while consistent, it's very difficult to reproduce the conditions that cause it. Unfortunately, I tried to create an example for you but wasn't' able to repro on a small scale.

I've tracked it down to Boot.js and the manner of listening for the readystate of the script node. It seems the use of onreadystatechange is not recommended for >=IE9 http://ift.tt/1ftttXj.

I have confirmed this by modifying boot.js to follow the pattern demonstrated in the MSDN article (using the load event and appending the script node to the head to initiate an async script load) and it fixes the problem.


I've attached a diff of the changes I made that seem to make loading in IE 9 more consistent.