Fixes #11426: getting the responseText of an xhr should be tried/caught because of IE's inability to give access to binary data. Unit test added.

src/ajax/xhr.js

@@ -148,7 +148,13 @@ if ( jQuery.support.ajax ) {
 									if ( xml && xml.documentElement /* #4958 */ ) {
 										responses.xml = xml;
 									}
-									responses.text = xhr.responseText;
+
+									// When requesting binary data, IE6-9 will throw an exception
+									// on any attempt to access responseText (#11426)
+									try {
+										responses.text = xhr.responseText;
+									} catch( _ ) {
+									}
 
 									// Firefox throws an exception when accessing
 									// statusText for faulty cross-domain requests

test/unit/ajax.js

@@ -2322,6 +2322,20 @@ test("jQuery.ajax - abort in prefilter", function() {
 
 });
 
+test( "jQuery.ajax - loading binary data shouldn't throw an exception in IE (#11426)", 1, function() {
+	stop();
+	jQuery.ajax( url( "data/1x1.jpg" ), {
+		success: function( data ) {
+			ok( data === undefined || /JFIF/.test( data ) , "success callback reached" );
+			start();
+		},
+		error: function( _, __, error ) {
+			ok( false, "exception thrown: '" + error + "'" );
+			start();
+		}
+	});
+});
+
 test("jQuery.ajax - active counter", function() {
     ok( jQuery.active == 0, "ajax active counter should be zero: " + jQuery.active );
 });