https://www.esakihome.co.jp/assets_new/js/kanseihirou_banner.js

1(function() {
2  var now = new Date();
3  var today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
4  for (var i = 0; i < SCHEDULES.length; i++) {
5    var s = SCHEDULES[i];
6    // 開催日は土曜なので-5で週初めの日付を取得
7    var monday = new Date(s.year, s.month - 1, s.date01 - 5);
8    // 最終開催日を取得
9    var lastDay = s.date01;
10    for (var j = 2; j <= 3; j++) {
11      var dk = 'date' + ('0' + j).slice(-2);
12      if (!s[dk] || s[dk] === '') break;
13      lastDay = s[dk];
14    }
15    var lastDate = new Date(s.year, s.month - 1, lastDay, 23, 59, 59);
16    if (today >= monday && today <= lastDate) {
17      var el = document.getElementById('mascot-kanseihirou');
18      el.style.display = 'block';
19      el.querySelector('img').src = s.yutorin_banner;
20      break;
21    }
22  }
23})();