Fullcalendar client-side event filtering with checkboxes

I have a well working fullcalendar script that adds css-classes to events according to data attributes via eventRender. I now need to filter these specific attributes with checkboxes, but I have no idea at all how I should get this going!

My script looks as follows:

<script>
    $(document).ready(function() {
        $('#calendar').fullCalendar({
            eventRender: function(calEvent, element, view) {
                if (calEvent.risk == "normal") {
                    element.css('background-color', '#99FF99');
                }
                if (calEvent.risk == "event") {
                    element.css('background-color', '#415eec');
                }
                if (calEvent.risk == "whisper") {
                    element.css('background-color', '#D7CDD5');
                }
            },
            allDaySlot: true,
            displayEventTime: true,
            displayEventEnd: true,
            editable: false,
            firstDay: 1,
            weekNumbers: true,
            selectable: false,
            weekNumberCalculation: "ISO",
            eventLimit: true, 
            events: 'parts/events22.php'
        });
    });
</script>

The html checkboxes:

<div class="checkbox">
  <label><input type="checkbox" value="normal">Normal</label>
</div>
<div class="checkbox">
  <label><input type="checkbox" value="event">Event</label>
</div>
<div class="checkbox">
  <label><input type="checkbox" value="whisper">Whisper</label>
</div>

Does someone know how I can connect the checkbox-values to calEvent.risk, i.e. specific data attributes so as to filter them? Or does someone have a different idea for multiselect filtering with fullcalendar? I'd be really grateful for any help!