设置秒数与毫秒数

<p id="demo">单击按钮显示修改后的秒数和毫秒数：</p>

<button onclick="myFunction()">点我</button>

<script>

  function myFunction() {

    var d = new Date();

    d.setSeconds(35, 825);

    var s = d.getSeconds();

    var ms = d.getMilliseconds();

    var x = document.getElementById("demo");

    x.innerHTML = s + ":" + ms;

  }

</script>