Question

我试图将两个输入字段相乘，并在总输入元素中显示结果。有人可以告诉我这段代码在哪里吗？

var amount = document.getElementById("amount").value;
var amount = parseInt(amount, 10);
var quantity = document.getElementById("quantity").value;
var quantity = parseInt(quantity, 10);
var total = amount * quantity;
document.getElementById("total").innerHTML = total;

Amount: <input type="number" id="amount" name="amount">
<br> Quantity: <input type="number" id="quantity" name="quantity">
<br> Total: <input type="number" id="total" name="total">

Answer 1

使用document.getElementById("total").value代替document.getElementById("total").innerHTML = total。另外，您需要在特定事件上触发代码。在这里，我刚刚将其设置为在用户使用两个输入字段上的oninput="calc()"属性向任一输入字段输入值时触发：

function calc() {
  var amount = document.getElementById("amount").value;
  var amount = parseInt(amount, 10);
  var quantity = document.getElementById("quantity").value;
  var quantity = parseInt(quantity, 10);
  var total = amount * quantity;
  document.getElementById("total").value = total;
}

Amount: <input type="number" id="amount" name="amount" oninput="calc();">
<br> Quantity: <input type="number" id="quantity" name="quantity" oninput="calc();">
<br> Total: <input type="number" id="total" name="total">

Answer 2

可能您需要将事件绑定到按钮（单击）或输入元素（输入）

在此示例中，按钮触发了计算。

以下调整：

将属性.value用于输入表单元素。
使用对象Number或加号+转换为数字。
验证输入的值（由您决定）。

document.getElementById('calculate').addEventListener('click', function() {
  var amount = document.getElementById("amount").value;
  var amount = +amount;
  var quantity = document.getElementById("quantity").value;
  var quantity = +quantity;
  var total = amount * quantity;
  document.getElementById("total").value = total;
});

Amount: <input type="number" id="amount" name="amount">
<br> Quantity: <input type="number" id="quantity" name="quantity">
<br>
<br> <input id='calculate' type='button' value='Calculate'>
<br>
<br> Total: <input type="number" id="total" name="total">

Answer 3

您应该添加一个函数，并在输入更改时调用它因此请尝试使用oninput事件并将document.getElementById("total").innerHTML = total;更改为document.getElementById("total").value = total;

<html><head></head><body>
Amount: <input type="number" oninput="calculate()" id="amount" name="amount">
<br>
Quantity: <input type="number" oninput="calculate()" id="quantity" name="quantity">
<br>
Total: <input type="number" id="total" name="total">

    
	<script>
		function calculate(){
			var amount = document.getElementById("amount").value;
			var amount = parseInt(amount, 10);
			var quantity = document.getElementById("quantity").value;
			var quantity = parseInt(quantity, 10);
			var total = amount * quantity;
			document.getElementById("total").value = total;
		}
	</script>
</body>
</html>

Answer 4

ffmpeg -i mysong.ogg -i coverart.jpg song_with_art.ogg

如何计算两个输入字段并使总显示在输入元素中

4 个答案: