<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>我是个大笨蛋</title>
</head>
<body>
<p>我是程锴大爹</p>
<script>
let title =document.querySelector('title');
//onfocus获取焦点
window.onfocus=function(){
zz= setTimeout(() => {
title.innerHTML='我是个大笨蛋'
}, 3000);
title.innerHTML='大爷,里面坐';
}
//onblur 失去焦点
window.onblur=function(){
clearTimeout(zz)
title.innerHTML='客官下次再来';
}
let zz= setTimeout(() => {
title.innerHTML='我是个大笨蛋'
}, 3000);
</script>
</body>
</html>