Scroll Reveal

Elements fade in as they scroll into view: IntersectionObserver, no JS needed.

core-ui/interactive ↗

Live

Scroll down: the box below fades up as it enters the view.
This box fades up when you scroll to it.

Example

box := html.Div(html.DivConfig{},
    ui.Box(ui.BoxConfig{Pad: ui.BoxPadXL, Outlined: true},
        render.Text("Fades up when scrolled into view.")))
interactive.Reveal(box, "fade-up") // or "fade-in", "slide-left", "slide-right"