slide-over

Nothing moves until the next page is ready; if that takes a while, a loader shows at the cursor. Then the next page slides up over this one, which shrinks and darkens as it’s covered. Going back, the same movement plays backwards: this page slides down and away, and the previous one comes forward out of the dark.

Both pages are on screen at once. The old page is a still copy kept in the layer, and the real new page slides in under it; the copy is cut away just ahead of the new page’s edge, so the new page seems to slide over it.