diff --git a/js/impress.js b/js/impress.js
index 13bec98c7..d7da550e6 100644
--- a/js/impress.js
+++ b/js/impress.js
@@ -304,13 +304,13 @@
         if ( select(target) ) {
             event.preventDefault();
         }
-    });
+    }, false);
     
-    document.addEventListener("mousewheel", function( event ) {        
+    document.addEventListener("mousewheel", function ( event ) {
         next = steps.indexOf( active ) - event.wheelDelta / Math.abs(event.wheelDelta);
         next = next >= 0 ? steps[ next ] : steps[ steps.length-1 ];
         select(next);
-    }, false); 
+    }, false);
     
     var getElementFromUrl = function () {
         // get id from url # by removing `#` or `#/` from the beginning,