Fix #12637: restore 1.8.1 ajax crossDomain logic. Close gh-944.

src/ajax.js

@@ -580,9 +580,12 @@ jQuery.extend({
 
 		// A cross-domain request is in order when we have a protocol:host:port mismatch
 		if ( s.crossDomain == null ) {
-			parts = rurl.exec( s.url.toLowerCase() ) || false;
-			s.crossDomain = parts && ( parts.join(":") + ( parts[ 3 ] ? "" : parts[ 1 ] === "http:" ? 80 : 443 ) ) !==
-				( ajaxLocParts.join(":") + ( ajaxLocParts[ 3 ] ? "" : ajaxLocParts[ 1 ] === "http:" ? 80 : 443 ) );
+			parts = rurl.exec( s.url.toLowerCase() );
+			s.crossDomain = !!( parts &&
+				( parts[ 1 ] !== ajaxLocParts[ 1 ] || parts[ 2 ] !== ajaxLocParts[ 2 ] ||
+					( parts[ 3 ] || ( parts[ 1 ] === "http:" ? 80 : 443 ) ) !=
+						( ajaxLocParts[ 3 ] || ( ajaxLocParts[ 1 ] === "http:" ? 80 : 443 ) ) )
+			);
 		}
 
 		// Convert data if not already a string

test/unit/ajax.js

@@ -511,12 +511,22 @@ test(".ajax() - hash", function() {
 
 test("jQuery ajax - cross-domain detection", function() {
 
-	expect( 6 );
+	expect( 7 );
 
 	var loc = document.location,
+		samePort = loc.port || ( loc.protocol === "http:" ? 80 : 443 ),
 		otherPort = loc.port === 666 ? 667 : 666,
 		otherProtocol = loc.protocol === "http:" ? "https:" : "http:";
 
+	jQuery.ajax({
+		dataType: "jsonp",
+		url: loc.protocol + "//" + loc.host + ":" + samePort,
+		beforeSend: function( _ , s ) {
+			ok( !s.crossDomain , "Test matching ports are not detected as cross-domain" );
+			return false;
+		}
+	});
+
 	jQuery.ajax({
 		dataType: "jsonp",
 		url: otherProtocol + "//" + loc.host,