IE9 ajax abort on unload requires Event module about jquery

[dmethvin]

You can't use onbeforeunload because one of the things that handler might do is ask "There are server requests in progress. Do you want to stop those, exit, and lose your work?" If the user were to cancel the damage would still be done.

I agree the dependency here is unfortunate and undesired.

[gibson042]

We could guard the whole block on jQuery.fn.on, though, basically restricting the fix to more complete builds.

[markelog]

We're not doing anything special for unload event in effects module and that hack is relative for oldIE only, plus we already have guard through checking for presence of ActiveXObject object (although this code path will be executed in newer version of IE).

So why we can't use attachEvent method directly?

[dmethvin]

@gibson042 Guarding the block works, and justifies not having it listed as a dependency I suppose.

@markelog I had remembered, falsely it seems, that unload didn't work with attachEvent. So perhaps we can just check for attachEvent as our feature detect and attach it that way? This problem is supposed to be fixed in IE11 where attachEvent isn't present.

[markelog]

So perhaps we can just check for attachEvent as our feature detect and attach it that way?

I think so, yes. I can provide patch today.