+ // #5280: we need to abort on unload or IE will keep connections alive
+ if ( ! xhrUnloadAbortMarker ) {
+
+ xhrUnloadAbortMarker = [];
+
+ jQuery(window).bind( "unload" , function() {
+
+ // Abort all pending requests
+ jQuery.each(xhrs, function(_, xhr) {
+ if ( xhr.onreadystatechange ) {
+ xhr.onreadystatechange( xhrUnloadAbortMarker );
+ }
+ });
+
+ // Reset polling structure to be safe
+ xhrs = {};
+
+ });
+ }
+
+ var xhr = xhrPool.pop() || s.xhr(),