[x/tour] tour: fix pageup/pagedown navigation on non-chrome browsers

FF and IE fail to populate event.keyCode, but instead populate
event.which with the key code. event.key is a DOMString of "PageUp"
or "PageDown" in this case, so remove the invalid comparision to a
numeric key code and instead compare the keycode to event.which.

Fixes golang/go#8829

Change-Id: I7192d2e561e2be5472018d8a3b06a91ab9dab49b
Reviewed-on: https://go-review.googlesource.com/15001
Reviewed-by: Andrew Gerrand <adg@golang.org>
X-Tour-Commit: aef6c802ede697bfc71a740ccd720cc12c6de29b

tour/static/js/directives.js

@@ -13,7 +13,7 @@ directive('onpageup', function() {
     return function(scope, elm, attrs) {
         elm.attr('tabindex', 0);
         elm.keyup(function(evt) {
-            var key = evt.key || evt.keyCode;
+            var key = evt.which || evt.keyCode;
             if (key == 33 && !evt.ctrlKey) {
                 scope.$apply(attrs.onpageup);
                 evt.preventDefault();
@@ -27,7 +27,7 @@ directive('onpagedown', function() {
     return function(scope, elm, attrs) {
         elm.attr('tabindex', 0);
         elm.keyup(function(evt) {
-            var key = evt.key || evt.keyCode;
+            var key = evt.which || evt.keyCode;
             if (key == 34 && !evt.ctrlKey) {
                 scope.$apply(attrs.onpagedown);
                 evt.preventDefault();