jQuery enables rich interactions: drag-and-drop, infinite scroll, lightboxes, typeaheads, counters, file uploads, and keyboard shortcuts. Always pair interactions with accessibility attributes (aria-expanded, aria-pressed, aria-label) and keyboard support.
// UI interaction checklist:
// [x] Debounce typeahead: 300ms after last keypress
// [x] IntersectionObserver for scroll-triggered effects
// [x] Event delegation for dynamically added elements
// [x] aria-expanded on toggle triggers
// [x] Escape key closes all overlays/modals
// [x] Focus management: return focus after dialog closes
// [x] Mobile touch events alongside click events
// [x] processData/contentType false for FormData uploadsInteractions are invisible when they work perfectly — users only notice them when they fail.