Tether is a JavaScript library for efficiently making an absolutely positioned element stay next to another element on the page. For example, you might want a tooltip or dialog to open, and remain, next to the relevant item on the page.
This positioning plugin includes the ability to constrain the element within the viewport, its scroll parent, any other element on the page, or a fixed bounding box. When it exceeds those constraints it can be pinned to the edge, flip to the other side of its
