<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>W3Cschool教程(w3cschool.cn)</title>
</head>
<body>
<p id="demo">单击按钮显示修改秒数后的时间</p>
<button onclick="myFunction()">点我</button>
<script>
function myFunction(){
var d = new Date();
d.setSeconds(35);
var x = document.getElementById("demo");
x.innerHTML=d;
}
</script>
</body>
</html>