IE9 XmlHttpRequest returns 12019 error instead of HTTP/417 response code

Question

I have some error processing for ajax request to WCF service on client side,

 self.remove = function (dep, processingResult) {
            var data = { \"id\": d         


        

Answer 1

If clearing the cache doesn't help, it's likely that this is related to how URLMon wraps certain HTTP error status codes; for instance IE9 and below would convert a HTTP/204 response into a bogus 1223 status code (see http://www.enhanceie.com/ie/bugs.asp)

This problem was fixed in IE10 such that the server's response status is correctly returned to the script.