These docs are for an old release. Info on upgrading to version 2/3
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eventMouseover

Triggered when the user mouses over an event.

function( event, jsEvent, view ) { }

event is an Event Object that holds the event’s information (date, title, etc).

jsEvent holds the native JavaScript event with low-level information such as mouse coordinates.

view holds the current View Object.

Within the callback function, this is set to the event’s <div> element.