diff --git a/src/ajax/ajax.js b/src/ajax/ajax.js
index fa047188..4b1e9b0e 100644
--- a/src/ajax/ajax.js
+++ b/src/ajax/ajax.js
@@ -622,7 +622,7 @@ jQuery.extend({
 		// Wait for a response to come back
 		var onreadystatechange = function(isTimeout){
 			// The transfer is complete and the data is available, or the request timed out
-			if ( xml && (xml.readyState == 4 || isTimeout == "timeout") ) {
+			if ( !requestDone && xml && (xml.readyState == 4 || isTimeout == "timeout") ) {
 				requestDone = true;
 				
 				// clear poll interval