An overlay component is a component that comes above the actual components in a absolute position.
In Html, it would have a higher value on the z scale (ie z-index)
When two elements overlay each other, they overlap.
Because they differ only in their characteristics, most libraries offer them all.
All these elements are overlays:
In Javascript, listen to the mouseup or mousedown not to the click event.
The reasons are:
Most software that will help to create overlay are positioning library