开启定时器 setInterval
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script>
function show() {
alert('a');
}
setInterval(show, 1000);
</script>
</head>
<body></body>
</html>
关闭定时器clearInterval
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>无标题文档</title>
<script>
window.onload = function() {
var oBtn1 = document.getElementById('btn1');
var oBtn2 = document.getElementById('btn2');
var timer = null;
oBtn1.onclick = function() {
timer = setInterval(function() {
alert('a');
}, 1000);
};
oBtn2.onclick = function() {
clearInterval(timer);
};
};
</script>
</head>
<body><input id="btn1" type="button" value="开启" /><input id="btn2" type="button" value="关闭" /></body>
</html>