eventClick
Triggered when the user clicks 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 click coordinates.
view holds the current View Object.
Within the callback function, this is set to the event’s <div> element.
Here is an example demonstrating all these variables:
$('#calendar').fullCalendar({
  eventClick: function(calEvent, jsEvent, view) {
    alert('Event: ' + calEvent.title);
    alert('Coordinates: ' + jsEvent.pageX + ',' + jsEvent.pageY);
    alert('View: ' + view.name);
    // change the border color just for fun
    $(this).css('border-color', 'red');
  }
});
Return Value
Normally, if the Event Object has its url property set, a click on the event will cause the browser to visit the event’s url (in the same window/tab). Returning false from within your function will prevent this from happening.
Often, developers want an event’s url to open in a different tab or a popup window. The following example shows how to do this:
$('#calendar').fullCalendar({
  events: [
    {
      title: 'My Event',
      start: '2010-01-01',
      url: 'https://google.com/'
    }
    // other events here
  ],
  eventClick: function(event) {
    if (event.url) {
      window.open(event.url);
      return false;
    }
  }
});
The window.open function can take many other options.