<html><body><p>更改后单击按钮显示秒数和毫秒数。</p><button onclick="myFunction()">试一试</button><p id="demo"></p><script>function myFunction() { var d = new Date(); d.setUTCSeconds(35, 825); var s = d.getUTCSeconds(); var ms = d.getUTCMilliseconds(); var x = document.getElementById("demo"); x.innerHTML = s + ":" + ms;}</script></body></html>