https://nakanoshima-terrace.com/js/view_timer.js

1//指定の日時に表示・非表示（jquery.min.js必要）
2$(document).ready(function() {
3  $(".view_timer").each(function(index, target) {
4    var startDate = $(this).attr("data-start-date");
5    var endDate = $(this).attr("data-end-date");
6    var nowDate = new Date();
7
8    if (startDate) {
9      startDate = new Date(startDate);
10    } else {
11      startDate = nowDate;
12    }
13    if (endDate) {
14      endDate = new Date(endDate);
15    }
16
17    if (startDate <= nowDate && (!endDate || nowDate <= endDate)) {
18      $(this).show();
19    } else {
20      $(this).hide();
21    }
22  });
23});