Question

我正在创建一个财务计算器。这是第一次。我希望表格将数字作为变量接收，并使用该变量表进行计算。我想使用表单，以便返回按钮可以提交条目。

当input为函数使用onchange侦听器时，此方法很好用。但是，当我尝试合并<input type="submit" />时，DOM会以正确的计算方式进行更新，然后立即消失。

使用onsubmit不能正常运行功能是什么？运行功能后，onsubmit是否刷新DOM？

解决此类问题的最佳实践是什么？

谢谢，会

HTML：

function update() {

  let initialGain = Number(document.getElementById('initialGain').value);
  let initialFedTax = initialGain * .238;
  let capAvail = initialGain - initialFedTax;
  let newValue = capAvail * (1+ .09 * 10);
  let newValueB = initialGain * (1+ .09 * 10);
  let tax85 = initialFedTax * .85
  let tax2029 = (newValue - capAvail) * .238;
  let afterTax = newValue - tax2029;
  let afterTaxB = newValueB - tax85;
  let netProfit = afterTax - initialGain;
  let netProfitB = afterTaxB - initialGain;

  // Capital Gain
  
  document.getElementById('capitalGain').innerHTML = "$" +  currency(initialGain);
  document.getElementById('capitalGainB').innerHTML = "$" + currency(initialGain);

  // Top Federal Tax Paid on Original Capital Gain, 23.8%

  document.getElementById('initialFedTax').innerHTML = "$" + currency(initialFedTax);
  
  // Capital Available for a "New Investment" in 2019

  document.getElementById('capAvail').innerHTML = "$" + currency(capAvail);
  document.getElementById('capAvailB').innerHTML = "$" + currency(initialGain);

  // Value of New Investment After 10 Years

  document.getElementById('newValue').innerHTML = "$" + currency(newValue);
  document.getElementById('newValueB').innerHTML = "$" + currency(newValueB);

  // Top Federal Tax on 85% of Original Gain due Dec 31, 2026

  document.getElementById('tax85').innerHTML = "(" + currency(tax85) + ")";

  // Top Federal Tax on Disposition of New Investment in 2029

  document.getElementById('tax2029').innerHTML = "(" + currency(tax2029) + ")";

  // After Tax Proceeds

  document.getElementById('afterTax').innerHTML = "(" + currency(afterTax) + ")";
  document.getElementById('afterTaxB').innerHTML = "(" + currency(afterTaxB) + ")";

  // Less: Original Gain

  document.getElementById('originalGain').innerHTML = "(" + currency(initialGain) + ")";
  document.getElementById('originalGainB').innerHTML = "(" + currency(initialGain) + ")";

  // Net Profit

  document.getElementById('netProfit').innerHTML = "$" + currency(netProfit);
  document.getElementById('netProfitB').innerHTML = "$" + currency(netProfitB);

  var x = document.getElementsByClassName('test')
  x[0].style.backgroundColor = 'red';
  x[0].style.width = '10px';
  x[0].style.height = '10px';

}

<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8">

    <link rel="stylesheet" type="text/css" href="calculator.css">
    <script src="calculator.js"></script>

  </head>
  <body>
    <h1>
      Calculator
    </h1>
    <form onsubmit=update()>
      <input 
        type="number"
        id="initialGain"
        placeholder="$1,000,000" />
      <input
        type="submit"
        value="click" />
    </form>
    <input
      type="checkbox"
      id="toggle" />
    <table>
      <caption>After-Tax Net Profit Investment Comparison</caption>
      <thead>
        <tr>
          <td></td>
          <td>TAXABLE GAINS<br/>(Long Term)</td>
          <td>1 American Elite™</td>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td><strong>Capital Gain</strong></td>
          <td id="capitalGain"></td>
          <td id="capitalGainB"></td>
        </tr>
        <tr>
          <td><strong>Top Federal Tax Paid on Original Gain</strong><br/><em>23.8%</em></td>
          <td id="initialFedTax"></td>
          <td id="rLong">-</td>
        </tr>
        <tr>
          <td><strong>Capital Available for a "New Investment" in 2019</strong></td>
          <td id="capAvail"></td>
          <td id="capAvailB"></td>
        </tr>    
        <tr>
          <td><strong>Value of New Investment after 10 years</strong> <br/> <em>9% Simple</em></td>
          <td id="newValue"></td>
          <td id="newValueB"></td>
        </tr>
        <tr>
          <td><strong>Top Federal Tax on 85% of Original Gain due Dec 31, 2026</strong><br/> <em>23.8%</em></td>
          <td></td>
          <td id="tax85"></td>
        </tr>
        <tr>
          <td><strong>Top Federal Tax on Disposition of New Investment in 2029</strong><br/> <em>23.8%</em></td>
          <td id="tax2029"></td>
          <td></td>
        </tr>
        <tr>
          <td><strong>After Tax Proceeds</strong></td>
          <td id="afterTax"></td>
          <td id="afterTaxB"></td>
        </tr>
        <tr>
          <td>Less: Original Gain</td>
          <td id="originalGain"></td>
          <td id="originalGainB"></td>
        </tr>
        <tr>
          <td><strong>Net Profit</strong><br/><em>(After Federal Tax on Original Gain and New Investment)</em></td>
          <td id="netProfit"></td>
          <td id="netProfitB"></td>
        </tr>
      </tbody>
    </table>
    <div class="test"></div>
  </body>
</html>

Answer 1

是的，默认情况下，onsubmit通过HTTP发送表单内容以进行服务器端处理，因此刷新了站点。为避免这种情况，请将return false;作为更新函数的最后一条语句，然后将onsubmit=update()替换为onsubmit="return update();"

要使其正常工作，您的函数必须没有错误。否则，将无法到达return false;行，并且浏览器会刷新页面。

表单onsubmit运行功能，但更改不会持久

1 个答案: