KevenHuang
一小时倒计时，代码如下：<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>js实现倒计时思路</title>
<style type="text/css">
*{
margin:0;
padding:0;
font-size:50px;
}
#wrap{
width:300px;
height:200px;
border:1px solid #abcdef;
position:absolute;
left:50%;
top:50%;
transform:translate(-50%,-50%);
text-align:center;
line-height:200px;
}
</style>
<script type="text/javascript">
window.onload = function(){
var hour = document.getElementById('hour');
var minute = document.getElementById('minute');
var second = document.getElementById('second');
var hourNum = 0;
var minuteNum = 59;
var secondNum = 60;
var timer = window.setInterval(function(){
if(secondNum!=0){
secondNum--;
if(secondNum<10){
secondNum = '0'+secondNum;
}
}else{
secondNum = 59;
//秒数为零时，时间走了一分钟，分钟数要减一
minuteNum--;
if(minuteNum<10&&minuteNum>0){
minuteNum = '0'+minuteNum;
}
}
if(minuteNum == 0){
//分钟数为零时，时间走了一小时，停止定时器
secondNum = '00';
minuteNum = '00';
window.clearInterval(timer);
}
hour.innerHTML = hourNum;
minute.innerHTML = minuteNum;
second.innerHTML = secondNum;
},1000);
}
</script>
</head>
<body>
<div id="wrap">
<span id="hour">1</span>:<span id="minute">00</span>:<span id="second">00</span>
</div>
</body>
</html>