Question

我已经建立了这个简单的租金负担能力的java脚本计算器，我有的问题是“Rent Affordability TextBox”有时可以返回的最后一个框 - （负数）我试图将该值设置为0.00如果数字变为负

我已将此添加到我的脚本中：

if (RentAffordability < 0) RentAffordability = 0.00;

没有运气。这是完整的代码：

<html lang="en-us">
<head></head>
<body>
  <script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
  <script>
    function run() {
      var PercentageRate = 40;
      var Income = parseInt(document.getElementById('YearlyIncome').value);
      var Expenses = parseInt(document.getElementById('MonthlyExpenses').value);
      var PercentageCalculated = Income / PercentageRate;

      //document.getElementById('RentAffordability').value = PercentageCalculated - Expenses;
      $('#RentAffordability').val((PercentageCalculated - Expenses).toFixed(2));
    }

    if (RentAffordability < 0) 
      RentAffordability = 0.00;
  </script>
  <script>
    (function($) {
      $.fn.currencyInput = function() {
        this.each(function() {
          var wrapper = $("<div class='currency-input' />");
          $(this).wrap(wrapper);
          $(this).change(function() {
            var min = parseFloat($(this).attr("min"));
            var max = parseFloat($(this).attr("max"));
            var value = this.valueAsNumber;
            if (value < min)
              value = min;
            else if (value > max)
              value = max;
            $(this).val(value.toFixed(2));
          });
        });
      };
    })(jQuery);

    $(document).ready(function() {
      $('input.currency').currencyInput();
    });
  </script>
  <table border="0" cellpadding="2" cellspacing="2">
    <tbody>
      <tr>
        <td>Combined Annual Income: </td>
        <td><input type="number" class="currency textBox" name="YearlyIncome" id="YearlyIncome" value="0.00" /></td>
      </tr>
      <tr>
        <td>Combined Monthly Expenses:</td>
        <td><input type="number" class="currency textBox" name="MonthlyExpenses" id="MonthlyExpenses" value="0.00" /></td>
      </tr>
      <tr>
        <td colspan="2" rowspan="1">&nbsp;</td>
      </tr>
      <tr>
        <td>Your Rent Affordability:</td>
        <td><input type="number" class="currency textBox" name="RentAffordability" id="RentAffordability" /></td>
      </tr>
      <tr>
        <td colspan="2" rowspan="1">&nbsp;</td>
      </tr>
      <tr>
        <td colspan="2" rowspan="1" style="padding-left: 250px;"><button onclick="run()">Calculate Your Rent</button></td>
      </tr>
    </tbody>
  </table>
</body>
</html>

Answer 1

使用RentAffordability = Math.max(0, RentAffordability)获取更大的0或RentAffordability的当前值。

当RentAffordability为负时，它会回落到0

Answer 2

我找到的一些问题

你的if语句不在运行函数
在检查是否为负数之前设置RentAffordability
你永远不会创建变量RentAffordability（我认为它应该是名称/ id为RentAffordability的输入标签）

更新代码应该是这样的：

function run() {
   var PercentageRate = 40;
   var Income = parseInt(document.getElementById('YearlyIncome').value);
              var Expenses = parseInt(document.getElementById('MonthlyExpenses').value);
   var PercentageCalculated = Income / PercentageRate;
   var RentAffordability = PercentageCalculated - Expenses
   if (RentAffordability < 0) 
      RentAffordability = 0.00;
   $('#RentAffordability').val((RentAffordability).toFixed(2));
}

如果数字为负，则将值设置为0.00

2 个答案: