I have a server process that takes 15-80 seconds to complete that is currently being requested via XMLHttpRequest in the background with a progress bar displayed to the end user while the request waits for the response.
I have modified the response to send back chunks of data as they are available so that the client can display the available data to the user.
The crux of it all is IE, of course, does not support multipart response. I am told that flash might be able to overcome this problem in IE. I found a flash impl of the XMLHttpRequest using haxe called SWFHttpRequest but it doesn't appear to fire readystatechange events until the response is complete ( which by the way is the way IE behaves without SWFHttoRequest )
I know that I could implement the http protocol on a flash9.net.Socket but I am worried about proxies etc that might not work with the Socket.