FullCalendar: Event with tooltips/custom event attributes

HTML

<link rel="stylesheet" href="http://arshaw.com/js/fullcalendar-1.5.3/fullcalendar/fullcalendar.css">
<script src="http://www.arshaw.com/js/fullcalendar-1.5.3/fullcalendar/fullcalendar.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.10.6/moment.min.js"></script>
<div style="border:solid 2px red;">
        <div id='calendar'></div>
</div>

JavaScript

$(document).ready(function() {

    var date = new Date();
    var d = date.getDate();
    var m = date.getMonth();
    var y = date.getFullYear();

    var events_array = [
        {
        title: 'Test1',
        start: new Date(2012, 8, 20),
        tip: 'Personal tip 1'},
    {
        title: 'Test2',
        start: new Date(2012, 8, 21),
        tip: 'Personal tip 2'}
    ];

    $('#calendar').fullCalendar({
        header: {
            left: 'prev,next today',
            center: 'title',
            right: 'month,agendaWeek,agendaDay'
        },
        selectable: true,
        events: events_array,
        eventRender: function(event, element) {
            element.attr('title', event.tip);
        },
        
           select: function(start, end, jsEvent, view) {
         // start contains the date you have selected
         // end contains the end date. 
         // Caution: the end date is exclusive (new since v2).
         var allDay = !start.hasTime && !end.hasTime;
         alert(["Event Start date: " + moment(start).format(),
                "Event End date: " + moment(end).format(),
                "AllDay: " + allDay].join("\n"));
    }
        
        
    });
});