Ajax: Don't throw exceptions on binary data response

Fixes jquerygh-2498
Closes jquerygh-2682

The added unit test shows how this could be used to support an
ArrayBuffer return, but $.ajax does not support it natively.
The goal with this change was to avoid the exception.

Author: dmethvin

src/ajax/xhr.js

@@ -97,12 +97,13 @@ jQuery.ajaxTransport( function( options ) {
 									xhrSuccessStatus[ xhr.status ] || xhr.status,
 									xhr.statusText,
 
-									// Support: IE9
-									// Accessing binary-data responseText throws an exception
-									// (#11426)
-									typeof xhr.responseText === "string" ? {
-										text: xhr.responseText
-									} : undefined,
+									// Support: IE9 only
+									// IE9 has no XHR2 but throws on binary (trac-11426)
+									// For XHR2 non-text, let the caller handle it (gh-2498)
+									( xhr.responseType || "text" ) !== "text"  ||
+									typeof xhr.responseText !== "string" ?
+										{ binary: xhr.response } :
+										{ text: xhr.responseText },
 									xhr.getAllResponseHeaders()
 								);
 							}

test/unit/ajax.js

@@ -1660,6 +1660,30 @@ QUnit.module( "ajax", {
 		};
 	} );
 
+if ( typeof window.ArrayBuffer === "undefined" || typeof new XMLHttpRequest().responseType !== "string" ) {
+
+	QUnit.skip( "No ArrayBuffer support in XHR", jQuery.noop );
+} else {
+
+	// No built-in support for binary data, but it's easy to add via a prefilter
+	jQuery.ajaxPrefilter( "arraybuffer", function ( s ) {
+		s.xhrFields = { responseType: "arraybuffer" };
+		s.responseFields.arraybuffer = "response";
+		s.converters[ "binary arraybuffer" ] = true;
+	});
+
+	ajaxTest( "gh-2498 - jQuery.ajax() - binary data shouldn't throw an exception", 2, function( assert ) {
+		return {
+			url: url( "data/1x1.jpg" ),
+			dataType: "arraybuffer",
+			success: function( data, s, jqxhr ) {
+				assert.ok( data instanceof window.ArrayBuffer, "correct data type" );
+				assert.ok( jqxhr.response instanceof window.ArrayBuffer, "data in jQXHR" );
+			}
+		};
+	} );
+}
+
 	QUnit.asyncTest( "#11743 - jQuery.ajax() - script, throws exception", 1, function( assert ) {
 
 		// Support: Android 2.3 only