<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>定时器</title>
<script>
window.onload=function(){
var btn1=document.getElementById("btn1");
var btn2=document.getElementById("btn2");
var time=null;
btn1.onclick=function(){
time= setInterval(function(){
alert(1);
},1000);
// time= setTimeout(function(){
// alert(1);
// },1000);
}
btn2.onclick=function(){
clearInterval(time);
// clearTimeout(time);
}
}
</script>
</head>
<body>
<input type="button" id="btn1" value="开启">
<input type="button" id="btn2" value="关闭">
</body>
</html>