MouseEvents dispatched when a pointing device is moved onto or off of an Element or one of its descendents. Similar to mouseover and mouseout respectively, but are not cancelable and are not dispatched more than one "round-trip" into an Element's boundary.
Docs: https://developer.mozilla.org/en-US/docs/Web/Events/mouseenter https://developer.mozilla.org/en-US/docs/Web/Events/mouseleave