JavaScript 公式语法不起作用

Question

我有以下公式，正在尝试将其转换为 JavaScript:

=(x*(y/120000)*(1+(y/120000))^(z))/((1+(y/120000))^z-1)

我使用了以下内容，但我认为语法不正确，但我无法找出原因!

var price = ((parseInt(x.value)*(parseInt(y.value)/1200)*(Math.pow(1+parseInt(y.value)/12000)),parseInt(z.value))) / (Math.pow((1+(parseInt(y.value)/1200),(parseInt(z.value)-1)));

我的整个表单脚本如下:

<form name="priceCalc" action="">
  <div align="center">
    <select name="loanamount" onchange="price();">
      <option value="130000">£130,000</option>
      <option value="160000">£160,000</option>
    </select>

    <select name="interestrate" onchange="price();">
      <option value="449">4.49%</option>
      <option value="500">5%</option>
    </select>

    <select name="numberpayments" onchange="price();">
      <option value="480">40yrs</option>
      <option value="360">30yrs</option>
    </select>

    <br>
    <div id="prices">Change items to see price</div>
  </div>
</form>

<script>
  function price() {
    var x = document.priceCalc.loanamount;
    var y = document.priceCalc.interestrate;
    var z = document.priceCalc.numberpayments;

    var price = ((parseInt(x.value)*(parseInt(y.value)/1200)*(Math.pow(1+parseInt(y.value)/12000)),parseInt(z.value))) / (Math.pow((1+(parseInt(y.value)/1200),(parseInt(z.value)-1)));

    document.getElementById("prices").innerHTML = 'Price: ' + price;
  }
</script>

任何帮助将不胜感激!

谢谢

Answer 1

=(x*(y/120000)*(1+(y/120000))^(z))/((1+(y/120000))^z-1)

翻译成类似

var x = parseInt(x.value,10), 
    y = parseInt(y.value,10)/120000, 
    z = parseInt(z.value,10)*12; // from your comments


var price = ( x*y*Math.pow(1+y,z) ) / (Math.pow(1+y,z)-1);
document.getElementById("prices").innerHTML ='Monthly repayment: £' + price.toFixed(2);

这是您的代码

window.onload = function() {
  document.priceCalc.loanamount.onchange = price;
  document.priceCalc.interestrate.onchange = price;
  document.priceCalc.numberpayments.onchange = price;

}

function price() {

    var x = parseInt(document.priceCalc.loanamount.value, 10);
    var y = parseInt(document.priceCalc.interestrate.value, 10) / 12000; 
    var z = parseInt(document.priceCalc.numberpayments.value,10)*12;

    var repayment = (x * y * Math.pow(1 + y, z)) / (Math.pow(1 + y, z) - 1); 
    console.log(x,y,z,x * y * Math.pow(1 + y, z),(Math.pow(1 + y, z) - 1),repayment)
  
    document.getElementById("prices").innerHTML = 'Monthly repayment: £' + isFinite(repayment) && !isNaN(repayment) && repayment != Number.POSITIVE_INFINITY?repayment.toFixed(2):"0.00";
}

<form name="priceCalc" action="">
  <div align="center">

    <select name="loanamount">
      <option value="0">Please select</option>
      <option value="130000">£130,000</option>
      <option value="160000">£160,000</option>
    </select>

    <select name="interestrate">
      <option value="0">Please select</option>
      <option value="449">4.49%</option>
      <option value="500">5%</option>
    </select>

    <select name="numberpayments">
      <option value="0">Please select</option>
      <option value="480">40yrs</option>
      <option value="360">30yrs</option>
    </select>

    <br>
    <div id="prices">Change items to see price</div>
  </div>
</form>