代码示例:(标识:jsck_round_2)
<!DOCTYPE html>
<html>
<body>

<p>单击按钮可将不同的数字四舍五入为最接近的整数。</p>

<button onclick="myFunction()">试一试</button>

<p id="demo"></p>

<script>
function myFunction() {
  var a = Math.round(2.60);
  var b = Math.round(2.50);
  var c = Math.round(2.49);
  var d = Math.round(-2.60);
  var e = Math.round(-2.50);
  var f = Math.round(-2.49);

  var x = a + "<br>" + b + "<br>" + c + "<br>" + d + "<br>" + e + "<br>" + f;
  document.getElementById("demo").innerHTML = x; 
}
</script>

</body>
</html>
运行结果: