Trial.js is a simple library to monitor mouse position and predict user input.
Scrollbear is a tool that maintains the container scroll position when images loaded.
When images loaded, the scroll position will jump and cause a unfriendly experience. Scrollbear will trace the container height and maintain the scroll position when the images loaded and container height change.
Tether includes the ability to constrain the element within the viewport, it's scroll parent, any other element on the page, or a fixed bounding box. When it exceedes those constraints it can be pinned to the edge, flip to the other side of it's target, or hide itself.