javascript - 不使用按钮计算平均值

Question

如何在html中计算平均值而不单击按钮显示结果，每次输入类型文本更改时，输出也会更改而无需单击按钮

function multiplyBy() {
  num1 = document.getElementById("firstNumber").value;
  num2 = document.getElementById("secondNumber").value;
  document.getElementById("result").innerHTML = num1 * num2;
}

function divideBy() {
  num1 = document.getElementById("firstNumber").value;
  num2 = document.getElementById("secondNumber").value;
  document.getElementById("result").innerHTML = num1 / num2;
}

<form>
  1st Number : <input type="text" id="firstNumber" /><br> 2nd Number: <input type="text" id="secondNumber" /><br>
  <input type="button" onClick="multiplyBy()" Value="Multiply" />
  <input type="button" onClick="divideBy()" Value="Divide" />
</form>
<p>The Result is : <br>
  <span id="result"></span>
</p>

Answer 1

为两个按钮添加一个input监听器:

const inputs = document.querySelectorAll('input');
for (const input of inputs) {
  input.addEventListener('input', () => {
    document.getElementById("result").textContent = (Number(inputs[0].value) + Number(inputs[1].value)) / 2;
  });
}

1st Number : <input type="text" id="firstNumber" /><br> 2nd Number: <input type="text" id="secondNumber" /><br>
<p>The Result is : <br>
  <span id="result"></span>
</p>