- 这个倒计时是不断变化的,因此需要定时器来自动变化(setInterval)
- 三个盒子里面分别存放时分秒
- 三个盒子利用 innerHTML 放入计算的小时分钟秒数
- 第一次执行也是间隔秒数,因此刚刷新页面是会有空白
- 最好采取封装函数的方式,这样可以想调用一次这个函数,防止刚开始刷新页面有空白的问题
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>倒计时</title>
<style>
span {
display: inline-block;
width: 30px;
height: 30px;
margin: 5px;
line-height: 30px;
text-align: center;
background-color: pink;
}
</style>
</head>
<body>
<div>
<span class="hour">1</span>
<span class="minute">2</span>
<span class="second">3</span>
</div>
<script>
var hour = document.querySelector('.hour');
var minute = document.querySelector('.minute');
var second = document.querySelector('.second');
var inputTime = +new Date('2020-5-20 10:00:00');
countDown();
setInterval(countDown, 1000);
function countDown() {
var nowTime = +new Date();
var times = (inputTime - nowTime) / 1000;
var h = parseInt(times / 60 / 60 % 24);
h = h < 10 ? '0' + h : h;
hour.innerHTML = h;
var m = parseInt(times / 60 % 60);
m = m < 10 ? '0' + m : m;
minute.innerHTML = m;
var s = parseInt(times % 60);
s = s < 10 ? '0' + s : s;
second.innerHTML = s;
}
</script>
</body>
</html>