Ajax: Do not execute scripts for unsuccessful HTTP responses

The script transport used to evaluate fetched script sources which is
undesirable for unsuccessful HTTP responses. This is different to other data
types where such a convention was fine (e.g. in case of JSON).

Fixes gh-4250
Closes gh-4379

1 files changed, 5 insertions, 0 deletions

diff --git a/src/ajax.js b/src/ajax.js
index c1f7b14d9..53557253f 100644
--- a/src/ajax.js
+++ b/src/ajax.js
@@ -748,6 +748,11 @@ jQuery.extend( {
 				response = ajaxHandleResponses( s, jqXHR, responses );
 			}
 
+			// Use a noop converter for missing script
+			if ( !isSuccess && jQuery.inArray( "script", s.dataTypes ) > -1 ) {
+				s.converters[ "text script" ] = function() {};
+			}
+
 			// Convert no matter what (that way responseXXX fields are always set)
 			response = ajaxConvert( s, response, jqXHR, isSuccess );