Hello Guys Today i will tell you through this tutorial how you can create lone calculator through javascript code. For this I will tell you step to step, so let’s go
Create Loan Calculator by Javascript or JQuery, How Can I Make Loan Calculator Using Javascript
To create loan calculator, you have to write script code in javascript. You can write these script code by making html file or you can create separate js file for it. You have to give html and script code of loan calculation below and along with css Code has also been written.
Step 1:- In this step you are given html code how you design the loan calculator in html
<!DOCTYPE html> <html> <head> <title>How to Create Loan Calculator Using Javascript?</title> </head> <body> <h2> JavaScript Loan Calculator </h2> <table> <tr><th>Enter Loan Data:</th> <td></td> <th>Loan Balance, Cumulative Equity, and Interest Payments</th></tr> <tr><td>Amount of the loan ($):</td> <td><input id="amount" onchange="calculate();"></td> <td rowspan=8> <canvas id="graph" width="400" height="250"></canvas></td></tr> <tr><td>Annual interest (%):</td> <td><input id="apr" onchange="calculate();"></td></tr> <tr><td>Repayment period (years):</td> <td><input id="years" onchange="calculate();"></td> <tr><td>Zipcode (to find lenders):</td> <td><input id="zipcode" onchange="calculate();"></td> <tr><th>Approximate Payments:</th> <td><button onclick="calculate();">Calculate</button></td></tr> <tr><td>Monthly payment:</td> <td>$<span class="output" id="payment"></span></td></tr> <tr><td>Total payment:</td> <td>$<span class="output" id="total"></span></td></tr> <tr><td>Total interest:</td> <td>$<span class="output" id="totalinterest"></span></td></tr> <tr><th>Sponsors:</th><td colspan=2> Apply for your loan with one of these fine lenders: <div id="lenders"></div></td></tr> </table> </body> </html>
Srep 2:- In this step you are given css code how you design the loan calculator of html page
.output {
font-weight:bold;
}
#payment {
text-decoration:underline;
}
#graph {
border:solid black 1px;
}
th, td {
vertical-align: top;
}
Step 3:- In this step you are given js code how you can calculate loan calculator. You can add this code to that file by making this js code a js file and then include the html by giving the path of this file. Or you can add the code of js to html file also.
function calculate() {
//Look up the input and output elements in the document
var amount = document.getElementById("amount");
var apr = document.getElementById("apr");
var years = document.getElementById("years");
var zipcode = document.getElementById("zipcode");
var payment = document.getElementById("payment");
var total = document.getElementById("total");
var totalinterest = document.getElementById("totalinterest");
// Get the user's input from the input elements.
// Convert interest from a percentage to a decimal, and convert from
// an annual rate to a monthly rate. Convert payment period in years
// to the number of monthly payments.
var principal = parseFloat(amount.value);
var interest = parseFloat(apr.value) / 100 / 12;
var payments = parseFloat(years.value) * 12;
// compute the monthly payment figure
var x = Math.pow(1 + interest, payments); //Math.pow computes powers
var monthly = (principal*x*interest)/(x-1);
// If the result is a finite number, the user's input was good and
// we have meaningful results to display
if (isFinite(monthly)){
// Fill in the output fields, rounding to 2 decimal places
payment.innerHTML = monthly.toFixed(2);
total.innerHTML = (monthly * payments).toFixed(2);
totalinterest.innerHTML = ((monthly*payments)-principal).toFixed(2);
// Save the user's input so we can restore it the next time they visit
save(amount.value, apr.value, years.value, zipcode.value);
// Advertise: find and display local lenders, but ignore network errors
try { // Catch any errors that occur within these curly braces
getLenders(amount.value, apr.value, years.value, zipcode.value);
}
catch(e) { /* And ignore those errors */ }
// Finally, chart loan balance, and interest and equity payments
chart(principal, interest, monthly, payments);
}
else {
// Result was Not-a-Number or infinite, which means the input was
// incomplete or invalid. Clear any previously displayed output.
payment.innerHTML = ""; // Erase the content of these elements
total.innerHTML = ""
totalinterest.innerHTML = "";
chart(); // With no arguments, clears the chart
}
}
// Save the user's input as properties of the localStorage object. Those
// properties will still be there when the user visits in the future
// This storage feature will not work in some browsers (Firefox, e.g.) if you
// run the example from a local file:// URL. It does work over HTTP, however.
function save(amount, apr, years, zipcode) {
if (window.localStorage) { // Only do this if the browser supports it
localStorage.loan_amount = amount;
localStorage.loan_apr = apr;
localStorage.loan_years = years;
localStorage.loan_zipcode = zipcode;
}
}
// Automatically attempt to restore input fields when the document first loads.
window.onload = function() {
// If the browser supports localStorage and we have some stored data
if (window.localStorage && localStorage.loan_amount) {
document.getElementById("amount").value = localStorage.loan_amount;
document.getElementById("apr").value = localStorage.loan_apr;
document.getElementById("years").value = localStorage.loan_years;
document.getElementById("zipcode").value = localStorage.loan_zipcode;
}
};
// Pass the user's input to a server-side script which can (in theory) return
// a list of links to local lenders interested in making loans. This example
// does not actually include a working implementation of such a lender-finding
// service. But if the service existed, this function would work with it.
function getLenders(amount, apr, years, zipcode) {
// If the browser does not support the XMLHttpRequest object, do nothing
if (!window.XMLHttpRequest) return;
// Find the element to display the list of lenders in
var ad = document.getElementById("lenders");
if (!ad) return; // Quit if no spot for output
// Encode the user's input as query parameters in a URL
var url = "getLenders.php" + // Service url plus
"?amt=" + encodeURIComponent(amount) + // user data in query string
"&apr=" + encodeURIComponent(apr) +
"&yrs=" + encodeURIComponent(years) +
"&zip=" + encodeURIComponent(zipcode);
// Fetch the contents of that URL using the XMLHttpRequest object
var req = new XMLHttpRequest(); // Begin a new request
req.open("GET", url); // An HTTP GET request for the url
req.send(null); // Send the request with no body
// Before returning, register an event handler function that will be called
// at some later time when the HTTP server's response arrives. This kind of
// asynchronous programming is very common in client-side JavaScript.
req.onreadystatechange = function() {
if (req.readyState == 4 && req.status == 200) {
// If we get here, we got a complete valid HTTP response
var response = req.responseText; // HTTP response as a string
var lenders = JSON.parse(response); // Parse it to a JS array
// Convert the array of lender objects to a string of HTML
var list = "";
for(var i = 0; i < lenders.length; i++) {
list += "<li><a href='" + lenders[i].url + "'>" +
lenders[i].name + "</a>";
}
// Display the HTML in the element from above.
ad.innerHTML = "<ul>" + list + "</ul>";
}
}
}
// Chart monthly loan balance, interest and equity in an HTML <canvas> element.
// If called with no arguments then just erase any previously drawn chart.
function chart(principal, interest, monthly, payments) {
var graph = document.getElementById("graph"); // Get the <canvas> tag
graph.width = graph.width; // Magic to clear and reset the canvas element
// If we're called with no arguments, or if this browser does not support
// graphics in a <canvas> element, then just return now.
if (arguments.length == 0 || !graph.getContext) return;
// Get the "context" object for the <canvas> that defines the drawing API
var g = graph.getContext("2d"); // All drawing is done with this object
var width = graph.width, height = graph.height; // Get canvas size
// These functions convert payment numbers and dollar amounts to pixels
function paymentToX(n) { return n * width/payments; }
function amountToY(a) { return height-(a * height/(monthly*payments*1.05));}
// Payments are a straight line from (0,0) to (payments, monthly*payments)
g.moveTo(paymentToX(0), amountToY(0)); // Start at lower left
g.lineTo(paymentToX(payments), // Draw to upper right
amountToY(monthly*payments));
g.lineTo(paymentToX(payments), amountToY(0)); // Down to lower right
g.closePath(); // And back to start
g.fillStyle = "#f88"; // Light red
g.fill(); // Fill the triangle
g.font = "bold 12px sans-serif"; // Define a font
g.fillText("Total Interest Payments", 20,20); // Draw text in legend
// Cumulative equity is non-linear and trickier to chart
var equity = 0;
g.beginPath(); // Begin a new shape
g.moveTo(paymentToX(0), amountToY(0)); // starting at lower-left
for(var p = 1; p <= payments; p++) {
// For each payment, figure out how much is interest
var thisMonthsInterest = (principal-equity)*interest;
equity += (monthly - thisMonthsInterest); // The rest goes to equity
g.lineTo(paymentToX(p),amountToY(equity)); // Line to this point
}
g.lineTo(paymentToX(payments), amountToY(0)); // Line back to X axis
g.closePath(); // And back to start point
g.fillStyle = "green"; // Now use green paint
g.fill(); // And fill area under curve
g.fillText("Total Equity", 20,35); // Label it in green
// Loop again, as above, but chart loan balance as a thick black line
var bal = principal;
g.beginPath();
g.moveTo(paymentToX(0),amountToY(bal));
for(var p = 1; p <= payments; p++) {
var thisMonthsInterest = bal*interest;
bal -= (monthly - thisMonthsInterest); // The rest goes to equity
g.lineTo(paymentToX(p),amountToY(bal)); // Draw line to this point
}
g.lineWidth = 3; // Use a thick line
g.stroke(); // Draw the balance curve
g.fillStyle = "black"; // Switch to black text
g.fillText("Loan Balance", 20,50); // Legend entry
// Now make yearly tick marks and year numbers on X axis
g.textAlign="center"; // Center text over ticks
var y = amountToY(0); // Y coordinate of X axis
for(var year=1; year*12 <= payments; year++) { // For each year
var x = paymentToX(year*12); // Compute tick position
g.fillRect(x-0.5,y-3,1,3); // Draw the tick
if (year == 1) g.fillText("Year", x, y-5); // Label the axis
if (year % 5 == 0 && year*12 !== payments) // Number every 5 years
g.fillText(String(year), x, y-5);
}
// Mark payment amounts along the right edge
g.textAlign = "right"; // Right-justify text
g.textBaseline = "middle"; // Center it vertically
var ticks = [monthly*payments, principal]; // The two points we'll mark
var rightEdge = paymentToX(payments); // X coordinate of Y axis
for(var i = 0; i < ticks.length; i++) { // For each of the 2 points
var y = amountToY(ticks[i]); // Compute Y position of tick
g.fillRect(rightEdge-3, y-0.5, 3,1); // Draw the tick mark
g.fillText(String(ticks[i].toFixed(0)), // And label it.
rightEdge-5, y);
}
}
If you want to create a loan calculator by adding the code of html, css and js to html file only, you can also do so that you have to give the code below of how to write all the code in the same file.
loan-calculator.html
<!DOCTYPE html>
<html>
<head>
<title>How to Create Loan Calculator Using Javascript?</title>
<style>
.output {
font-weight:bold;
}
#payment {
text-decoration:underline;
}
#graph {
border:solid black 1px;
}
th, td {
vertical-align: top;
}
</style>
</head>
<body>
<h2> JavaScript Loan Calculator </h2>
<table>
<tr><th>Enter Loan Data:</th>
<td></td>
<th>Loan Balance, Cumulative Equity, and Interest Payments</th></tr>
<tr><td>Amount of the loan ($):</td>
<td><input id="amount" onchange="calculate();"></td>
<td rowspan=8>
<canvas id="graph" width="400" height="250"></canvas></td></tr>
<tr><td>Annual interest (%):</td>
<td><input id="apr" onchange="calculate();"></td></tr>
<tr><td>Repayment period (years):</td>
<td><input id="years" onchange="calculate();"></td>
<tr><td>Zipcode (to find lenders):</td>
<td><input id="zipcode" onchange="calculate();"></td>
<tr><th>Approximate Payments:</th>
<td><button onclick="calculate();">Calculate</button></td></tr>
<tr><td>Monthly payment:</td>
<td>$<span class="output" id="payment"></span></td></tr>
<tr><td>Total payment:</td>
<td>$<span class="output" id="total"></span></td></tr>
<tr><td>Total interest:</td>
<td>$<span class="output" id="totalinterest"></span></td></tr>
<tr><th>Sponsors:</th><td colspan=2>
Apply for your loan with one of these fine lenders:
<div id="lenders"></div></td></tr>
</table>
</body>
<script>
function calculate() {
//Look up the input and output elements in the document
var amount = document.getElementById("amount");
var apr = document.getElementById("apr");
var years = document.getElementById("years");
var zipcode = document.getElementById("zipcode");
var payment = document.getElementById("payment");
var total = document.getElementById("total");
var totalinterest = document.getElementById("totalinterest");
// Get the user's input from the input elements.
// Convert interest from a percentage to a decimal, and convert from
// an annual rate to a monthly rate. Convert payment period in years
// to the number of monthly payments.
var principal = parseFloat(amount.value);
var interest = parseFloat(apr.value) / 100 / 12;
var payments = parseFloat(years.value) * 12;
// compute the monthly payment figure
var x = Math.pow(1 + interest, payments); //Math.pow computes powers
var monthly = (principal*x*interest)/(x-1);
// If the result is a finite number, the user's input was good and
// we have meaningful results to display
if (isFinite(monthly)){
// Fill in the output fields, rounding to 2 decimal places
payment.innerHTML = monthly.toFixed(2);
total.innerHTML = (monthly * payments).toFixed(2);
totalinterest.innerHTML = ((monthly*payments)-principal).toFixed(2);
// Save the user's input so we can restore it the next time they visit
save(amount.value, apr.value, years.value, zipcode.value);
// Advertise: find and display local lenders, but ignore network errors
try { // Catch any errors that occur within these curly braces
getLenders(amount.value, apr.value, years.value, zipcode.value);
}
catch(e) { /* And ignore those errors */ }
// Finally, chart loan balance, and interest and equity payments
chart(principal, interest, monthly, payments);
}
else {
// Result was Not-a-Number or infinite, which means the input was
// incomplete or invalid. Clear any previously displayed output.
payment.innerHTML = ""; // Erase the content of these elements
total.innerHTML = ""
totalinterest.innerHTML = "";
chart(); // With no arguments, clears the chart
}
}
// Save the user's input as properties of the localStorage object. Those
// properties will still be there when the user visits in the future
// This storage feature will not work in some browsers (Firefox, e.g.) if you
// run the example from a local file:// URL. It does work over HTTP, however.
function save(amount, apr, years, zipcode) {
if (window.localStorage) { // Only do this if the browser supports it
localStorage.loan_amount = amount;
localStorage.loan_apr = apr;
localStorage.loan_years = years;
localStorage.loan_zipcode = zipcode;
}
}
// Automatically attempt to restore input fields when the document first loads.
window.onload = function() {
// If the browser supports localStorage and we have some stored data
if (window.localStorage && localStorage.loan_amount) {
document.getElementById("amount").value = localStorage.loan_amount;
document.getElementById("apr").value = localStorage.loan_apr;
document.getElementById("years").value = localStorage.loan_years;
document.getElementById("zipcode").value = localStorage.loan_zipcode;
}
};
// Pass the user's input to a server-side script which can (in theory) return
// a list of links to local lenders interested in making loans. This example
// does not actually include a working implementation of such a lender-finding
// service. But if the service existed, this function would work with it.
function getLenders(amount, apr, years, zipcode) {
// If the browser does not support the XMLHttpRequest object, do nothing
if (!window.XMLHttpRequest) return;
// Find the element to display the list of lenders in
var ad = document.getElementById("lenders");
if (!ad) return; // Quit if no spot for output
// Encode the user's input as query parameters in a URL
var url = "getLenders.php" + // Service url plus
"?amt=" + encodeURIComponent(amount) + // user data in query string
"&apr=" + encodeURIComponent(apr) +
"&yrs=" + encodeURIComponent(years) +
"&zip=" + encodeURIComponent(zipcode);
// Fetch the contents of that URL using the XMLHttpRequest object
var req = new XMLHttpRequest(); // Begin a new request
req.open("GET", url); // An HTTP GET request for the url
req.send(null); // Send the request with no body
// Before returning, register an event handler function that will be called
// at some later time when the HTTP server's response arrives. This kind of
// asynchronous programming is very common in client-side JavaScript.
req.onreadystatechange = function() {
if (req.readyState == 4 && req.status == 200) {
// If we get here, we got a complete valid HTTP response
var response = req.responseText; // HTTP response as a string
var lenders = JSON.parse(response); // Parse it to a JS array
// Convert the array of lender objects to a string of HTML
var list = "";
for(var i = 0; i < lenders.length; i++) {
list += "<li><a href='" + lenders[i].url + "'>" +
lenders[i].name + "</a>";
}
// Display the HTML in the element from above.
ad.innerHTML = "<ul>" + list + "</ul>";
}
}
}
// Chart monthly loan balance, interest and equity in an HTML <canvas> element.
// If called with no arguments then just erase any previously drawn chart.
function chart(principal, interest, monthly, payments) {
var graph = document.getElementById("graph"); // Get the <canvas> tag
graph.width = graph.width; // Magic to clear and reset the canvas element
// If we're called with no arguments, or if this browser does not support
// graphics in a <canvas> element, then just return now.
if (arguments.length == 0 || !graph.getContext) return;
// Get the "context" object for the <canvas> that defines the drawing API
var g = graph.getContext("2d"); // All drawing is done with this object
var width = graph.width, height = graph.height; // Get canvas size
// These functions convert payment numbers and dollar amounts to pixels
function paymentToX(n) { return n * width/payments; }
function amountToY(a) { return height-(a * height/(monthly*payments*1.05));}
// Payments are a straight line from (0,0) to (payments, monthly*payments)
g.moveTo(paymentToX(0), amountToY(0)); // Start at lower left
g.lineTo(paymentToX(payments), // Draw to upper right
amountToY(monthly*payments));
g.lineTo(paymentToX(payments), amountToY(0)); // Down to lower right
g.closePath(); // And back to start
g.fillStyle = "#f88"; // Light red
g.fill(); // Fill the triangle
g.font = "bold 12px sans-serif"; // Define a font
g.fillText("Total Interest Payments", 20,20); // Draw text in legend
// Cumulative equity is non-linear and trickier to chart
var equity = 0;
g.beginPath(); // Begin a new shape
g.moveTo(paymentToX(0), amountToY(0)); // starting at lower-left
for(var p = 1; p <= payments; p++) {
// For each payment, figure out how much is interest
var thisMonthsInterest = (principal-equity)*interest;
equity += (monthly - thisMonthsInterest); // The rest goes to equity
g.lineTo(paymentToX(p),amountToY(equity)); // Line to this point
}
g.lineTo(paymentToX(payments), amountToY(0)); // Line back to X axis
g.closePath(); // And back to start point
g.fillStyle = "green"; // Now use green paint
g.fill(); // And fill area under curve
g.fillText("Total Equity", 20,35); // Label it in green
// Loop again, as above, but chart loan balance as a thick black line
var bal = principal;
g.beginPath();
g.moveTo(paymentToX(0),amountToY(bal));
for(var p = 1; p <= payments; p++) {
var thisMonthsInterest = bal*interest;
bal -= (monthly - thisMonthsInterest); // The rest goes to equity
g.lineTo(paymentToX(p),amountToY(bal)); // Draw line to this point
}
g.lineWidth = 3; // Use a thick line
g.stroke(); // Draw the balance curve
g.fillStyle = "black"; // Switch to black text
g.fillText("Loan Balance", 20,50); // Legend entry
// Now make yearly tick marks and year numbers on X axis
g.textAlign="center"; // Center text over ticks
var y = amountToY(0); // Y coordinate of X axis
for(var year=1; year*12 <= payments; year++) { // For each year
var x = paymentToX(year*12); // Compute tick position
g.fillRect(x-0.5,y-3,1,3); // Draw the tick
if (year == 1) g.fillText("Year", x, y-5); // Label the axis
if (year % 5 == 0 && year*12 !== payments) // Number every 5 years
g.fillText(String(year), x, y-5);
}
// Mark payment amounts along the right edge
g.textAlign = "right"; // Right-justify text
g.textBaseline = "middle"; // Center it vertically
var ticks = [monthly*payments, principal]; // The two points we'll mark
var rightEdge = paymentToX(payments); // X coordinate of Y axis
for(var i = 0; i < ticks.length; i++) { // For each of the 2 points
var y = amountToY(ticks[i]); // Compute Y position of tick
g.fillRect(rightEdge-3, y-0.5, 3,1); // Draw the tick mark
g.fillText(String(ticks[i].toFixed(0)), // And label it.
rightEdge-5, y);
}
}
</script>
</html>