DragEffect

When dragging, there are several operations that may be performed. The copy operation is used to indicate that the data being dragged will be copied from its present location to the drop location. The move operation is used to indicate that the data being dragged will be moved, and the link operation is used to indicate that some form of relationship or connection will be created between the source and drop locations.

You can specify which of the three operations are allowed for a drag source by setting the effectAllowed property within a dragstart event listener.

Note that these values must be used exactly as defined below.

https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Drag_operations#drageffects