沒有工作的Javascript公式語法

Question

我有以下的公式，我試圖將其轉換爲JavaScript：

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

我用下面，但我不認爲語法是正確的，但我不能工作爲什麼！

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))); 

我的整個形式腳本如下：

<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> 

任何幫助將不勝感激！

感謝

Answer 1

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

轉化成像

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); 

這裏是你的代碼

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>

Answer 2

var price = ((parseInt(x.value)*(parseInt(y.value)/120000)*(Math.pow(1+parseInt(y.value)/120000),parseInt(z.value)))/(Math.pow((1+(parseInt(y.value)/120000),(parseInt(z.value)-1))))); 

此外，在您的頂線，你有/120000但在你的計算你有/1200

而且按照gillesc的建議：

var x = parseInt(x.value); 
var y = parseInt(y.value); 
var z = parseInt(z.value); 
var price = ((x*(y/120000)*(Math.pow((1+y)/120000),z))/(Math.pow((1+(y/120000),(z-1))))); 

Answer 3

請嘗試以下更新公式： -

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

Answer 4

我發現在最後一個辦法：

window.onload = function() { 
 
    document.repaymentcalc.loanamount.onchange = repayment; 
 
    document.repaymentcalc.interestrate.onchange = repayment; 
 
    document.repaymentcalc.numberpayments.onchange = repayment; 
 

 
} 
 

 
function repayment() { 
 

 
    var x = parseInt(document.repaymentcalc.loanamount.value, 10); 
 
    var y = parseInt(document.repaymentcalc.interestrate.value, 10)/120000; 
 
    var z = parseInt(document.repaymentcalc.numberpayments.value, 10) * 12; 
 

 
    var repayment = y * x * Math.pow((1 + y), z)/(Math.pow((1 + y), z) - 1); 
 

 
    document.getElementById("repayments").innerHTML = 'Monthly repayment: £' + repayment.toFixed(2); 
 
}

<form name="repaymentcalc" action=""> 
 
    <div align="center"> 
 
    </br> 
 
    Loan Amount 
 
    <select name="loanamount"> 
 
     <option value="100000">£100,000</option> 
 
     <option value="200000">£200,000</option> 
 
     <option value="300000">£300,000</option> 
 
     <option value="400000">£400,000</option> 
 
    </select> 
 
    </p> 
 
    Interest Rate 
 
    <select name="interestrate"> 
 
     <option value="100">1.00%</option> 
 
     <option value="200">2.00%</option> 
 
     <option value="300">3.00%</option> 
 
    </select> 
 
    </p> 
 
    Term 
 
    <select name="numberpayments"> 
 
     <option value="5">5yrs</option> 
 
     <option value="10">10yrs</option> 
 
    </select> 
 
    </p> 
 
    <br> 
 
    <div id="repayments">Monthly repayment: £837.85</div> 
 
    </div> 
 
</form>