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Question

我非常新的JavaScript來，但我一直負責創建一個腳本，將數字汽車貸款每月的還款額。我做了一個函數，接受貸款金額，貸款期限和利率的輸入，以便我可以計算具體的每月付款。我還希望能夠向用戶顯示每月付款，如果他們獲得更長的貸款時間，如36,48或60個月。我用一個循環來改變貸款長度的變量來做到這一點，但我不知道如何讓函數接受循環創建的不同長度。也許我正在談論這一切都是錯誤的。

這是我到目前爲止有：

function payment(monthly_interest_rate, loan_amount, loan_length) { 
 
    var base = Math.pow(1 + monthly_interest_rate, loan_length); 
 
    var payment = loan_amount * monthly_interest_rate/(1 - (1/base)); 
 
    return payment; 
 
} 
 

 

 
var vehicle_price = parseInt(prompt("How much does the vehicle cost?")); 
 
var down_payment = parseInt(prompt("How much is the down payment?")); 
 
var interest_rate = parseFloat(prompt("What is the interest rate?")); 
 
var loan_amount = vehicle_price - down_payment; 
 
var monthly_interest_rate = interest_rate/1200; 
 
var loan_length = parseInt(prompt("How many months is the loan?")); 
 

 
document.write("Vehicle price: $" + vehicle_price + "<br>"); 
 
document.write("Down payment: $" + down_payment + "<br>"); 
 
document.write("Interest rate: " + interest_rate + "%" + "<br>"); 
 
document.write("Loan Amount: $ " + loan_amount + "<br>"); 
 

 

 
document.write("Number of months: " + "<br>"); 
 
for (loan_length = 24; loan_length < 61; loan_length += 12) { 
 
    document.write(loan_length + "<br>"); 
 
} 
 

 

 
var monthly_payment = payment(monthly_interest_rate, loan_amount, loan_length).toFixed(2); 
 

 

 

 
document.write("<br>" + "Monthly payment"); 
 
document.write("<br>" + "$" + monthly_payment);

<h1>Loan Calculator</h1>

Answer 1

這是你在找什麼？

function payment(monthly_interest_rate, loan_amount, loan_length) { 
 
    var base = Math.pow(1 + monthly_interest_rate, loan_length); 
 
return loan_amount * monthly_interest_rate/(1 - (1/base)); 
 
} 
 

 

 
var vehicle_price = 1000 
 
var down_payment = 200 
 
var interest_rate = 1.5 
 
var loan_amount = vehicle_price - down_payment; 
 
var monthly_interest_rate = interest_rate/1200; 
 
var loan_length = 12 
 

 
document.write("Vehicle price: $" + vehicle_price + "<br>"); 
 
document.write("Down payment: $" + down_payment + "<br>"); 
 
document.write("Interest rate: " + interest_rate + "%" + "<br>"); 
 
document.write("Loan Amount: $ " + loan_amount + "<br>"); 
 

 

 
var range = [12,24,36,48] 
 
for (x=0; x < range.length; x++) { 
 
    
 
    document.write("Loan for " + range[x] + " months: <br>"); 
 
    var monthly_payment = payment(monthly_interest_rate, loan_amount, range[x]).toFixed(2); 
 
    document.write(monthly_payment + "<br>"); 
 
    
 
}

<h1>Loan Calculator</h1>