Ajax: trigger error callback on native abort

- IE9 does not have onabort. Use onreadystatechange instead.

Fixes gh-2079
Close gh-2684

src/ajax/xhr.js

@@ -25,7 +25,7 @@ support.cors = !!xhrSupported && ( "withCredentials" in xhrSupported );
 support.ajax = xhrSupported = !!xhrSupported;
 
 jQuery.ajaxTransport( function( options ) {
-	var callback;
+	var callback, errorCallback;
 
 	// Cross domain only allowed if supported through XMLHttpRequest
 	if ( support.cors || xhrSupported && !options.crossDomain ) {
@@ -72,17 +72,26 @@ jQuery.ajaxTransport( function( options ) {
 				callback = function( type ) {
 					return function() {
 						if ( callback ) {
-							callback = xhr.onload = xhr.onerror = null;
+							callback = errorCallback = xhr.onload =
+								xhr.onerror = xhr.onabort = xhr.onreadystatechange = null;
 
 							if ( type === "abort" ) {
 								xhr.abort();
 							} else if ( type === "error" ) {
-								complete(
 
-									// File: protocol always yields status 0; see #8605, #14207
-									xhr.status,
-									xhr.statusText
-								);
+								// Support: IE9
+								// On a manual native abort, IE9 throws
+								// errors on any property access that is not readyState
+								if ( typeof xhr.status !== "number" ) {
+									complete( 0, "error" );
+								} else {
+									complete(
+
+										// File: protocol always yields status 0; see #8605, #14207
+										xhr.status,
+										xhr.statusText
+									);
+								}
 							} else {
 								complete(
 									xhrSuccessStatus[ xhr.status ] || xhr.status,
@@ -103,7 +112,31 @@ jQuery.ajaxTransport( function( options ) {
 
 				// Listen to events
 				xhr.onload = callback();
-				xhr.onerror = callback( "error" );
+				errorCallback = xhr.onerror = callback( "error" );
+
+				// Support: IE9
+				// Use onreadystatechange to replace onabort
+				// to handle uncaught aborts
+				if ( xhr.onabort !== undefined ) {
+					xhr.onabort = errorCallback;
+				} else {
+					xhr.onreadystatechange = function() {
+
+						// Check readyState before timeout as it changes
+						if ( xhr.readyState === 4 ) {
+
+							// Allow onerror to be called first,
+							// but that will not handle a native abort
+							// Also, save errorCallback to a variable
+							// as xhr.onerror cannot be accessed
+							window.setTimeout( function() {
+								if ( callback ) {
+									errorCallback();
+								}
+							} );
+						}
+					};
+				}
 
 				// Create the abort callback
 				callback = callback( "abort" );

test/unit/ajax.js

@@ -38,7 +38,7 @@ QUnit.module( "ajax", {
 	);
 
 	ajaxTest( "jQuery.ajax() - success callbacks", 8, function( assert ) {
-	    return {
+		return {
 			setup: addGlobalEvents( "ajaxStart ajaxStop ajaxSend ajaxComplete ajaxSuccess", assert ),
 			url: url( "data/name.html" ),
 			beforeSend: function() {
@@ -437,6 +437,25 @@ QUnit.module( "ajax", {
 		};
 	} );
 
+	ajaxTest( "jQuery.ajax() - native abort", 2, function( assert ) {
+		return {
+			url: url( "data/name.php?wait=1" ),
+			xhr: function() {
+				var xhr = new window.XMLHttpRequest();
+				setTimeout( function() {
+					xhr.abort();
+				}, 100 );
+				return xhr;
+			},
+			error: function( xhr, msg ) {
+				assert.strictEqual( msg, "error", "Native abort triggers error callback" );
+			},
+			complete: function() {
+				assert.ok( true, "complete" );
+			}
+		};
+	} );
+
 	ajaxTest( "jQuery.ajax() - events with context", 12, function( assert ) {
 		var context = document.createElement( "div" );