Loader is never used without ckeditor.js which sets basePath.

core/loader.js

@@ -76,39 +76,6 @@ if ( !CKEDITOR.loader ) {
 			'creators/inline': []
 		};
 
-		var basePath = ( function() {
-			// This is a copy of CKEDITOR.basePath, but requires the script having
-			// "_source/loader.js".
-			if ( CKEDITOR && CKEDITOR.basePath )
-				return CKEDITOR.basePath;
-
-			// Find out the editor directory path, based on its <script> tag.
-			var path = '';
-			var scripts = document.getElementsByTagName( 'script' );
-
-			for ( var i = 0; i < scripts.length; i++ ) {
-				var match = scripts[ i ].src.match( /(^|.*?[\\\/])(?:_source\/)?core\/loader.js(?:\?.*|;.*)?$/i );
-
-				if ( match ) {
-					path = match[ 1 ];
-					break;
-				}
-			}
-
-			// In IE (only) the script.src string is the raw valued entered in the
-			// HTML. Other browsers return the full resolved URL instead.
-			if ( path.indexOf( '://' ) == -1 ) {
-				// Absolute path.
-				if ( path.indexOf( '/' ) === 0 )
-					path = location.href.match( /^.*?:\/\/[^\/]*/ )[ 0 ] + path;
-				// Relative path.
-				else
-					path = location.href.match( /^[^\?]*\// )[ 0 ] + path;
-			}
-
-			return path;
-		} )();
-
 		var timestamp = ( CKEDITOR && CKEDITOR.timestamp ) || ( new Date() ).valueOf(); // %REMOVE_LINE%
 		/*																				// %REMOVE_LINE%
 		 * The production implementation contains a fixed timestamp						// %REMOVE_LINE%
@@ -120,7 +87,7 @@ if ( !CKEDITOR.loader ) {
 				if ( CKEDITOR && CKEDITOR.getUrl )
 					return CKEDITOR.getUrl( resource );
 
-				return basePath + resource + ( resource.indexOf( '?' ) >= 0 ? '&' : '?' ) + 't=' + timestamp;
+				return CKEDITOR.basePath + resource + ( resource.indexOf( '?' ) >= 0 ? '&' : '?' ) + 't=' + timestamp;
 			};
 
 		var pendingLoad = [];