基于JS代码实现简单易用的倒计时 x 天 x 时 x 分 x 秒效果

<script> (function () {  var tian = document.getElementsByClassName('JS-tian')[0];  var shi = document.getElementsByClassName('JS-shi')[0];  var fen = document.getElementsByClassName('JS-fen')[0];  var miao = document.getElementsByClassName('JS-miao')[0];  var endTime = new Date('2117/07/12 23:59:59').getTime() + 1000;  var interval = null;  interval = setInterval(function () {   var syhm = endTime - Date.now(); // 剩余毫秒   if (syhm >= 0) {    tian.innerText = Math.floor(syhm / 1000 / 60 / 60 / 24);    shi.innerText = Math.floor(syhm / 1000 / 60 / 60 % 24);    fen.innerText = Math.floor(syhm / 1000 / 60 % 60);    miao.innerText = Math.floor(syhm / 1000 % 60);   } else {    clearInterval(interval);   }  }, 0); })();</script>

<div> 距结束还剩：<span class="JS-tian"></span>天<span class="JS-shi"></span>时<span class="JS-fen"></span>分<span class="JS-miao"></span>秒</div>