JS实现随机抽选数字
<!DOCTYPE html>
<html lang="zh">
<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></title>
</head>
<body>
<button id="start">启动</button>
<button id="stop">停止</button>
<div id="num"></div>
<script type="text/javascript">
var start = document.getElementById('start')
var stop = document.getElementById('stop')
var num = document.getElementById('num')
var intv = null
start.onclick = function(){
if(intv == undefined){
intv = setInterval(()=>{
num.innerHTML = Math.floor(Math.random()*30)
},10)
}
}
stop.onclick = function(){
clearInterval(intv)
intv = null
}
</script>
</body>
</html>
