diff --git a/js/reveal.js b/js/reveal.js
index 8edf66a..14b3685 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 ) {