diff --git a/js/reveal.js b/js/reveal.js
index 8edf66a3f147c023b91c375218331400e01e4f03..14b3685f63c9b4dec26e7d98ec5d9011a65d199a 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -3716,7 +3716,10 @@
 				v = parseInt( bits[1], 10 ) || 0,
 				f;
 			if( config.fragmentInURL ) {
-				f = parseInt( bits[2], 10 ) || undefined;
+				f = parseInt( bits[2], 10 );
+				if( isNaN( f ) ) {
+					f = undefined;
+				}
 			}
 
 			if( h !== indexh || v !== indexv || f !== undefined ) {