enable mouse wheel scrolling

1 files changed, 8 insertions, 0 deletions

diff --git a/index.html b/index.html
index a7b0463..d7cb540 100644
--- a/index.html
+++ b/index.html
@@ -108,6 +108,14 @@
             var stepped = d3.select(e.target).selectAll(".stepped")[0];
             stepped[stepped.length-1].classList.add("lastInnerstep");
         });
+
+        document.addEventListener("wheel", function(e) {
+            if (e.wheelDelta > 0) {
+                impress().prev();
+            } else {
+                impress().next();
+            }
+        });
     </script>
 
     <div class="bar" id="progressBar"><div></div></div>