javascript - 使用 JavaScript 计算税金

Question

所以我的问题是如何将函数calculate()添加到HTML代码中以便动态更改税收输入。例如，如果我在收入字段中写入 10'000，则税金应显示 3'500，如果我在财富字段中另外添加 10'000，则税金应显示 5'000。

HTML:

var income = document.getElementById('income').value;
var wealth = document.getElementById('wealth').value;
var tax = document.getElementById('tax');

function calculate() {
  tax.innerHTML = (0.35 * income) + (0.25 * wealth);
}

<div class="row">
  <div class="col1">
    <label for="income">Income:</label>
  </div>
  <div class="col2">
    <input type="number" name="income" min="0" id="income" oninput="calculate()" required><br>
  </div>
</div>

<div class="row">
  <div class="col1">
    <label for="wealth">Wealth:</label>
  </div>
  <div class="col2">
    <input type="number" name="wealth" min="0" id="wealth" oninput="calculate()" required><br>
  </div>
</div>

<div class="row">
  <div class="col1">
    <label for="tax">Tax:</label>
  </div>
  <div class="col2">
    <input type="number" name="tax" min="0" id="tax" disabled>
  </div>
</div>

Answer 1

var incomeEl = document.getElementById('income')
var wealthEl = document.getElementById('wealth')
var taxEl    = document.getElementById('tax');

function calculate() {  
  var incomeTax = 0.35 * incomeEl.value;
  var wealthTax = 0.25 * wealthEl.value;
  var tax =  incomeTax + wealthTax;

  // round with 2 decimal places
  taxEl.value = Math.round(tax * 100) / 100;
}

incomeEl.addEventListener('input', calculate);
wealthEl.addEventListener('input', calculate);

<div class="row">
  <div class="col1">
    <label for="income">Income:</label>
  </div>
  <div class="col2">
    <input type="number" name="income" min="0" id="income" required><br>
  </div>
</div>

<div class="row">
  <div class="col1">
    <label for="wealth">Wealth:</label>
  </div>
  <div class="col2">
    <input type="number" name="wealth" min="0" id="wealth" required><br>
  </div>
</div>

<div class="row">
  <div class="col1">
    <label for="tax">Tax:</label>
  </div>
  <div class="col2">
    <input type="number" name="tax" min="0" id="tax" disabled>
  </div>
</div>