Fix #14379: AJAX requests on unload

src/ajax/xhr.js

@@ -18,18 +18,16 @@ var xhrSupported = jQuery.ajaxSettings.xhr(),
 		// #1450: sometimes IE returns 1223 when it should be 204
 		1223: 204
 	},
-	// Support: IE9
-	// We need to keep track of outbound xhr and abort them manually
-	// because IE is not smart enough to do it all by itself
 	xhrId = 0,
 	xhrCallbacks = {};
 
+// Support: IE9
+// Open requests must be manually aborted on unload (#5280)
 if ( window.ActiveXObject ) {
 	jQuery( window ).on( "unload", function() {
 		for ( var key in xhrCallbacks ) {
 			xhrCallbacks[ key ]();
 		}
-		xhrCallbacks = undefined;
 	});
 }
 

test/data/ajax/onunload.html

+<!doctype html>
+<html>
+<head>
+	<meta http-equiv="Content-type" content="text/html; charset=utf-8"/>
+	<title>onunload ajax requests (#14379)</title>
+	<script src="../../jquery.js"></script>
+</head>
+<body>
+	<form id="navigate" action="about:blank"></form>
+	<script>
+		jQuery( window ).on( "unload", function() {
+			var ajaxStatus;
+			jQuery.ajax({
+				url: "../name.html",
+				async: false,
+				complete: function( xhr, status ) {
+					ajaxStatus = status;
+				}
+			});
+			parent.iframeCallback( ajaxStatus );
+		});
+
+		jQuery(function() {
+			setTimeout(function() {
+				document.getElementById( "navigate" ).submit();
+			}, 0 );
+		});
+	</script>
+</body>
+</html>

test/unit/ajax.js

@@ -1522,6 +1522,11 @@ module( "ajax", {
 		}
 	} );
 
+	testIframeWithCallback( "#14379 - jQuery.ajax() on unload", "ajax/onunload.html", function( status ) {
+		expect( 1 );
+		strictEqual( status, "success", "Request completed" );
+	});
+
 //----------- jQuery.ajaxPrefilter()
 
 	ajaxTest( "jQuery.ajaxPrefilter() - abort", 1, {