<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
input{
text-align: right;
font-weight:bold;
}
</style>
</head>
<body>
minutes:<input type="text" value="0" >
seconds:<input type="text" value="0">
<script type="text/javascript">
var minutesCode=document.getElementsByTagName('input')[0];
var secondsCode=document.getElementsByTagName('input')[1];
var seconds=0,
minutes=0;
var timer= setInterval(function (){
seconds++;
if(seconds==60){
minutes++;
seconds=0;
}
secondsCode.value=seconds;
minutesCode.value=minutes;
if(minutes==3){
clearInterval(timer);
}
},10)
// setInterval(function (){
// console.log('s');
// },200) //////定时器
// var firstTime=new Date().getTime();
// setInterval(function (){
// var lastTime=new Date().getTime();
// console.log(lastTime-firstTime);
// firstTime=lastTime;
// },1000);
</script>
</body>
</html>
//setInterval()
setTiemout()推迟一段时间在执行
clearInterval()
clearTimeout()
