There are still quite a few older (but still globally-popular) browsers that don't support the 'wheel' event, which is why the check was in there, even if it wasn't quite correct. I suggest something like this (adapted from [MDN](https://developer.mozilla.org/en-US/docs/Web/Reference/Events/wheel#Listening_to_this_event_across_browser)):
```javascript
var wheel = 'onwheel' in element ? 'wheel' : document.onmousewheel !== undefined ? 'mousewheel' : 'DOMMouseScroll';
$(element).on(wheel, function (e) { core.wheelScroll(element, e); });
```