JavaScript 实现倒计时功能及 Date 对象用法详解

倒计时核心逻辑与DOM操作

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>h
<style>
#box {
 width: 100%;
 height: 400px;
 background: black;
 color: #fff;
 font-size:40px;
 line-height:400px;
 text-align:center;
}
</style>
<script>
window.onload = function(){
 var oBox = document.getElementById('box');
 var oDate = new Date();//获取当前时间;
 oDate.setFullYear(2016,11,31);//自动进位；
 oDate.setHours(0,0,0,0);

 function countDown(){
  //未来时间戳减去现在时间的时间戳;
  var ms = oDate.getTime() - new Date().getTime();

  //毫秒转换成秒
  var oSec = parseInt(ms/1000);

  //秒转换成天
  var oDay = parseInt(oSec/86400);

  //不到一天剩下的秒数;
  oSec%=86400;

  //转换成小时
  var oHour = parseInt(oSec/3600);

  //不到一小时剩下的秒数;
  oSec%=3600;

  //转换成分钟
  var oMin = parseInt(oSec/60);

  //不到一分钟剩下的秒数;
  oSec%=60;

  oBox.innerHTML = '距离2016年12月31日还有:'+oDay+'天'+oHour+'时'+oMin+'分'+oSec+'秒';
 } 
 countDown();
 setInterval(countDown,1000);
}
</script>
</head>

<body>
<div id="box">距离2016年12月31日还有:xx天xx时xx分xx秒</div>
</body>
</html>

  var oDate = new Date();
  oYear = oDate.getFullYear();
  oMon = oDate.getMonth();
  oDay = oDate.getDate();
  oHou = oDate.getHours();
  oMin = oDate.getMinutes();
  oSec = oDate.getSeconds();
  oWeek = oDate.getDay();

  oDate.setFullYear(年,月,日);
  oDate.setMonth(月);
  oDate.setDate(日);
  oDate.setHours(时,分,秒,毫秒);
  时间会自动进位;