https://www.tigerscu.org/calc.js

1// Code By Avtec ( https://avtecmedia.com )
2// Listen for Submit
3document.getElementById("loan-form").addEventListener("submit", function(e) {
4  // Hide Results
5  document.getElementById("result").style.display = "none";
6
7  // Show Loader
8  document.getElementById("loading").style.display = "block";
9
10  setTimeout(calculateResults, 2000);
11
12  e.preventDefault();
13});
14
15// Calculate Results
16function calculateResults() {
17
18  const amount = document.getElementById("amount");
19  const interest = document.getElementById("interest");
20  const years = document.getElementById("years");
21  const monthlyPayment = document.getElementById("monthly-payment");
22  const totalPayment = document.getElementById("total-payment");
23  const totalInterest = document.getElementById("total-interest");
24
25  const principal = parseFloat(amount.value);
26  const calculatedInterest = parseFloat(interest.value) / 100 / 12;
27  const calculatedPayments = parseFloat(years.value) * 12;
28
29  // Computed Monthly payment
30  const x = Math.pow(1 + calculatedInterest, calculatedPayments);
31  const monthly = (principal * x * calculatedInterest) / (x - 1);
32
33  if (isFinite(monthly)) {
34    monthlyPayment.value = monthly.toFixed(2);
35    totalPayment.value = (monthly * calculatedPayments).toFixed(2);
36    totalInterest.value = (monthly * calculatedPayments - principal).toFixed(2);
37
38    // Show Results
39    document.getElementById("result").style.display = "block";
40
41    // Hide Loader
42    document.getElementById("loading").style.display = "none";
43  } else {
44    showError("Please check number inputs");
45  }
46}
47
48// Show Error
49function showError(error) {
50  // Hide Results
51  document.getElementById("result").style.display = "none";
52
53  // Hide Loader
54  document.getElementById("loading").style.display = "none";
55
56  // Create a div
57  const errorDiv = document.createElement("div");
58
59  // Get Elements
60  const card = document.querySelector(".card");
61  const heading = document.querySelector(".heading");
62
63  // Add class
64  errorDiv.className = "alert alert-danger";
65
66  // Create text node and append div
67  errorDiv.appendChild(document.createTextNode(error));
68
69  // Insert error above heading
70  card.insertBefore(errorDiv, heading);
71
72  // Clear Error after 3 seconds
73  setTimeout(clearError, 3000);
74
75  // Clear Error
76  function clearError() {
77    document.querySelector(".alert").remove();
78  }
79}