Fix for aborted requests in IE9 #1

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tlianza commented Dec 25, 2011


I noticed your code referenced from here: and when I tried it out, it worked perfectly in IE8, but not on IE9. It looks like for IE9, you need to define the onprogress handler or requests will abort:

From my testing, setting this handler to jQuery.noop wasn't sufficient, but the empty function is.

Hope this helps someone!


Thank you guys for working on this. Julian, what are your thoughts on merging that one line to make this work in IE9?


jaubourg commented May 3, 2012

@troyharvey I'm all for it. I'd just like to have a unit test to go with it.

I'm also doubtful about jQuery.noop not working and I think leaving an anonymous function on the xdr may cause the closure within which it is defined to leak -- it's IE we're talking about. Thing is I never found the time to tackle this.

tlianza commented May 3, 2012

@jaubourg Was there ever a unit test for it? Happy to update it if you point me in the right direction.


jaubourg commented May 3, 2012

No there is none, and that's the problem, I'd need a unit test and do all the usual careful testing but I just didn't find the time :(


jaubourg commented Sep 25, 2012

@jeroenooms I'm convinced your specific case is a miscommunication between IE and your server that is not related to the issue at hand.

I tried my best to reproduce the issue... to no avail. No-one provided an actual reduced test case that would demonstrate the issue. I lost countless hours because of that.

I added a unit test to tentatively trigger onprogress handlers (and thus trigger the error) here: Of course, it doesn't trigger anything but if someone wants to take this as a first step to demonstrate the bug, be my guest.

I added an onprogress handler set to noop and I now always set the timeout property and companion ontimeout handler (it seems the XDomainRequest instance can act weirdly if some field/handler is not set or so I read on the interweb). I also re-ordered everything so that open and send are called after setting the handlers and properties. Why? Because I suspect we have a race condition here which would explain the non-reliably-repeatable nature of this non-sense. Even if I didn't experience the bug, ever.

So, if someone wants to make a unit test that demonstrates the problem, you'd probably have to reset back to the transport as it was before.

I officially give up on this one: I couldn't reproduce the issue but I read stuff on the web and acted accordingly. Now, if you have a bug related to the XDomainRequest transport, open a new ticket with a reduced test case demonstrating the issue: if there is no test case, the ticket will be closed, period. Sorry to be that abrupt but I don't have enough hair to lose on wild goose chases, especially when IE and its horrid, stupid, outrageously useless dev tools are involved.

jaubourg closed this Sep 25, 2012

nelsonmenezes referenced this pull request in MoonScript/jQuery-ajaxTransport-XDomainRequest Dec 3, 2012


Fix for IE9 bug which causes some requests to abort #8

I had a request that worked a couple of hours ago in a Virtualbox Win7 image which was not fully up-to-date with patches. I rebooted, updates were applied and then the same request was aborted. This patch made it work again.

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