https://www.akeno-clinic.jp/wp-content/plugins/xo-event-calendar/js/ajax.js?ver=1.9.0

1jQuery(function ($) {
2  xo_event_calendar_month = function (id, month, event, categories, holidays, prev, next, start_of_week, months, navigation) {
3    target = $('#' + id);
4    target.prop('disabled', true);
5    target.addClass('xoec-loading');
6    $.ajax({
7      type: 'POST',
8      url: xo_event_calendar_object.ajax_url,
9      data: {
10        'action': xo_event_calendar_object.action,
11        'id': id,
12        'month': month,
13        'event': event,
14        'categories': categories,
15        'holidays': holidays,
16        'prev': prev,
17        'next': next,
18        'start_of_week': start_of_week,
19        'months': months,
20        'navigation': navigation
21      },
22      datatype: 'html',
23      success: function (response) {
24        target.removeClass('xoec-loading');
25        target.find(".xo-months").html(response);
26      },
27      error: function () {
28      }
29    });
30    return false;
31  };
32});