<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="countdown">还剩 30 分 00 秒</div>
<script>
window.onload=function(){
var countdown=document.getElementById("countdown")
var time=1800
setInterval(function(){
time=time-1
var minute=parseInt(time/60)
var second=parseInt(time%60)
countdown.innerHTML='还剩'+minute+'分'+second+'秒'
},1000)
}
</script>
</body>
</html>
<p id="time1"></p>
<p id="time2"></p>
<p id="time3"></p>
<p id="time4"></p>
var outTime = function (time, id){
var countdown= document.getElementById(id)
setInterval(function(){
time= time - 1
var minute= parseInt(time/60)
var second= parseInt(time%60)
countdown.innerHTML= "剩余00:00:" + minute+':'+second
},1000)
}
outTime(1800, "time1")
outTime(1200, "time2")
outTime(1700, "time3")
outTime(1650, "time4")