en.javascript.info/2-ui/3-event-details/4-mouse-drag-and-drop/2-drag-heroes/solution.md

To drag the element we can use position:fixed, it makes coordinates easier to manage. At the end we should switch it back to position:absolute to lay the element into the document.

When coordinates are at window top/bottom, we use window.scrollTo to scroll it.

More details in the code, in comments.