dragStart :- fires when the user starts dragging the element.
dragEnter :- fires when the draggable element is first dragged over the target element.
dragOver :- fires when the mouse is moved over an element when the drag is occurring.
dragLeave :- fired if the user’s cursor leaves an element when dragging.
drag : - fires every time we move the mouse during the dragging of our element.
drop : - fired when the actual drop is performed.
dragEnd :- fires when the user releases the mouse while dragging the object.
