JavaScript positioning fallback for browsers without CSS anchor positioning.
Places floating relative to anchor with flip + shift collision handling,
setting inline position/top/left plus data-hl-side/data-hl-align
for CSS to react to (e.g. arrow direction). Modern engines never call this:
the stylesheet positions floating surfaces declaratively. No-ops gracefully
when the anchor has no layout box (e.g. jsdom).
JavaScript positioning fallback for browsers without CSS anchor positioning. Places
floatingrelative toanchorwith flip + shift collision handling, setting inlineposition/top/leftplusdata-hl-side/data-hl-alignfor CSS to react to (e.g. arrow direction). Modern engines never call this: the stylesheet positions floating surfaces declaratively. No-ops gracefully when the anchor has no layout box (e.g. jsdom).