I'm using a mousewheel / wheel event to zoom in/out on my page. When I call it with el.on("mousewheel DOMMouseScroll", functionName) jQuery handler, it runs smoothly and everything works fine, event.delta has consistent values.

On the other hand, when I call the same function with el.addEventListener("wheel", functionName), the scroll is all over the place, sometimes it triggers, sometimes it doesn't, event.deltaY changes the sign depending on how it feels at the moment, unrelated to the direction of my wheel.

Is there a way to achieve the smoothness of the jQuery event without loading the whole library only for that single purpose? How would I go about writing/finding the equivalent?

Solved: The event wasn't causing the stutter, event.deltaY property was. Javascript wheel property event.wheelDeltaY is the equivalent to jQuery's event.delta.

Object documentation Thank you @CBroe