Function cb

static/js/jquery.form.js:612–784

(e)

            var data, doc, domCheckCount = 50, callbackProcessed;

            function cb(e) {
                if (xhr.aborted || callbackProcessed) {
                    return;
                }

                doc = getDoc(io);
                if(!doc) {
                    log('cannot access response document');
                    e = SERVER_ABORT;
                }
                if (e === CLIENT_TIMEOUT_ABORT && xhr) {
                    xhr.abort('timeout');
                    deferred.reject(xhr, 'timeout');
                    return;
                }
                else if (e == SERVER_ABORT && xhr) {
                    xhr.abort('server abort');
                    deferred.reject(xhr, 'error', 'server abort');
                    return;
                }

                if (!doc || doc.location.href == s.iframeSrc) {
                    // response not received yet
                    if (!timedOut) {
                        return;
                    }
                }
                if (io.detachEvent) {
                    io.detachEvent('onload', cb);
                }
                else {
                    io.removeEventListener('load', cb, false);
                }

                var status = 'success', errMsg;
                try {
                    if (timedOut) {
                        throw 'timeout';
                    }

                    var isXml = s.dataType == 'xml' || doc.XMLDocument || $.isXMLDoc(doc);
                    log('isXml='+isXml);
                    if (!isXml && window.opera && (doc.body === null || !doc.body.innerHTML)) {
                        if (--domCheckCount) {
                            // in some browsers (Opera) the iframe DOM is not always traversable when
                            // the onload callback fires, so we loop a bit to accommodate
                            log('requeing onLoad callback, DOM not available');
                            setTimeout(cb, 250);
                            return;
                        }
                        // let this fall through because server response could be an empty document
                        //log('Could not access iframe DOM after mutiple tries.');
                        //throw 'DOMException: not available';
                    }

                    //log('response detected');
                    var docRoot = doc.body ? doc.body : doc.documentElement;
                    xhr.responseText = docRoot ? docRoot.innerHTML : null;