Prevent scrolling of parent element when inner element scroll position reaches top/bottom? [duplicate]

Answer 1

New web dev here. This worked like a charm for me on both IE and Chrome.

static preventScrollPropagation(e: HTMLElement) {
    e.onmousewheel = (ev) => {
        var preventScroll = false;
        var isScrollingDown = ev.wheelDelta < 0;
        if (isScrollingDown) {
            var isAtBottom = e.scrollTop + e.clientHeight == e.scrollHeight;
            if (isAtBottom) {
                preventScroll = true;
            }
        } else {
            var isAtTop = e.scrollTop == 0;
            if (isAtTop) {
                preventScroll = true;
            }
        }
        if (preventScroll) {
            ev.preventDefault();
        }
    }
}

Don't let the number of lines fool you, it is quite simple - just a bit verbose for readability (self documenting code ftw right?)

Also I should mention that the language here is TypeScript, but as always, it is straightforward to convert it to JS.