Ajax: use anchor tag for parsing urls

Fixes gh-1875
Closes gh-1880

src/ajax.js

@@ -17,7 +17,6 @@ var
 	rlocalProtocol = /^(?:about|app|app-storage|.+-extension|file|res|widget):$/,
 	rnoContent = /^(?:GET|HEAD)$/,
 	rprotocol = /^\/\//,
-	rurl = /^([\w.+-]+:)(?:\/\/(?:[^\/?#]*@|)([^\/?#:]*)(?::(\d+)|)|)/,
 
 	/* Prefilters
 	 * 1) They are useful to introduce custom dataTypes (see ajax/jsonp.js for an example)
@@ -40,11 +39,9 @@ var
 	// Avoid comment-prolog char sequence (#10098); must appease lint and evade compression
 	allTypes = "*/".concat( "*" ),
 
-	// Document location
-	ajaxLocation = location.href,
-
-	// Segment location into parts
-	ajaxLocParts = rurl.exec( ajaxLocation.toLowerCase() ) || [];
+	// Anchor tag for parsing the document origin
+	originAnchor = document.createElement( "a" );
+	originAnchor.href = location.href;
 
 // Base "constructor" for jQuery.ajaxPrefilter and jQuery.ajaxTransport
 function addToPrefiltersOrTransports( structure ) {
@@ -288,9 +285,9 @@ jQuery.extend({
 	etag: {},
 
 	ajaxSettings: {
-		url: ajaxLocation,
+		url: location.href,
 		type: "GET",
-		isLocal: rlocalProtocol.test( ajaxLocParts[ 1 ] ),
+		isLocal: rlocalProtocol.test( location.protocol ),
 		global: true,
 		processData: true,
 		async: true,
@@ -390,8 +387,8 @@ jQuery.extend({
 			responseHeaders,
 			// timeout handle
 			timeoutTimer,
-			// Cross-domain detection vars
-			parts,
+			// Url cleanup var
+			urlAnchor,
 			// To know if global events are to be dispatched
 			fireGlobals,
 			// Loop variable
@@ -496,23 +493,33 @@ jQuery.extend({
 		// Add protocol if not provided (prefilters might expect it)
 		// Handle falsy url in the settings object (#10093: consistency with old signature)
 		// We also use the url parameter if available
-		s.url = ( ( url || s.url || ajaxLocation ) + "" ).replace( rhash, "" )
-			.replace( rprotocol, ajaxLocParts[ 1 ] + "//" );
+		s.url = ( ( url || s.url || location.href ) + "" ).replace( rhash, "" )
+			.replace( rprotocol, location.protocol + "//" );
 
 		// Alias method option to type as per ticket #12004
 		s.type = options.method || options.type || s.method || s.type;
 
 		// Extract dataTypes list
 		s.dataTypes = jQuery.trim( s.dataType || "*" ).toLowerCase().match( rnotwhite ) || [ "" ];
 
-		// A cross-domain request is in order when we have a protocol:host:port mismatch
+		// A cross-domain request is in order when the origin doesn't match the current origin.
 		if ( s.crossDomain == null ) {
-			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" ) ) )
-			);
+			urlAnchor = document.createElement( "a" );
+
+			// Support: IE8-11+
+			// IE throws exception if url is malformed, e.g. http://example.com:80x/
+			try {
+				urlAnchor.href = s.url;
+				// Support: IE8-11+
+				// Anchor's host property isn't correctly set when s.url is relative
+				urlAnchor.href = urlAnchor.href;
+				s.crossDomain = originAnchor.protocol + "//" + originAnchor.host !==
+					urlAnchor.protocol + "//" + urlAnchor.host;
+			} catch ( e ) {
+				// If there is an error parsing the URL, assume it is crossDomain,
+				// it can be rejected by the transport if it is invalid
+				s.crossDomain = true;
+			}
 		}
 
 		// Convert data if not already a string

test/unit/ajax.js

@@ -301,7 +301,7 @@ module( "ajax", {
 		}
 	]);
 
-	ajaxTest( "jQuery.ajax() - cross-domain detection", 7, function() {
+	ajaxTest( "jQuery.ajax() - cross-domain detection", 8, function() {
 		function request( url, title, crossDomainOrOptions ) {
 			return jQuery.extend( {
 				dataType: "jsonp",
@@ -351,6 +351,10 @@ module( "ajax", {
 				{
 					crossDomain: true
 				}
+			),
+			request(
+				" http://otherdomain.com",
+				"Cross-domain url with leading space is detected as cross-domain"
 			)
 		];
 	});