代码示例:(标识:js_callback_4)
<!DOCTYPE html>
<html>
<body>

<h1>JavaScript 回调</h1>

<p>进行计算,然后显示结果。</p>

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

<script>
function myDisplayer(some) {
  document.getElementById("demo").innerHTML = some;
}

function myCalculator(num1, num2, myCallback) {
  let sum = num1 + num2;
  myCallback(sum);
}

myCalculator(5, 5, myDisplayer);
</script>

</body>
</html>
运行结果: