The Code

                        
                            "use strict";

                            //Calculate the payment for the loan
                            function calcPayment(amount, rate, term) {
                                return (amount * (rate / 1200)) / (1 - Math.pow(1 + rate / 1200, -term));
                            }
                            
                            //calculate the interst for the current balance of the loan
                            function calcInterest(balance, rate) {
                                return balance * (rate / 1200);
                            }
                            
                            //Build the amoritization schedule
                            function buildSchedule() {
                                let amount = document.getElementById("lamount").value;
                                let rate = document.getElementById("lrate").value;
                                let term = document.getElementById("lterm").value;
                            
                                //get the table we are going to add to.
                                let tableBody = document.getElementById("scheduleBody");
                                let template = document.getElementById("scheduleTemplate");
                            
                                //clear the table for previous calculations
                                tableBody.innerHTML = "";
                            
                                //setup some variables to hold the value in the schedule
                                let payment = calcPayment(amount, rate, term);
                                let balance = amount;
                                let totalInterest = 0;
                                let monthlyPrincipal = 0;
                                let monthlyInterest = 0;
                                let monthlyTotalInterest = 0;
                            
                                //create a loop for each month of the loan term
                                for (let month = 1; month <= term; month++) {
                                monthlyInterest = calcInterest(balance, rate);
                                totalInterest += monthlyInterest;
                                monthlyPrincipal = payment - monthlyInterest;
                                balance = balance - monthlyPrincipal;
                            
                                //get a clone row template
                                let clone = template.content.cloneNode(true);
                                //grab only the columns in the template
                                let columns = clone.querySelectorAll("td");
                            
                                //build the row
                                //we know that there are six columns in our template
                                columns[0].textContent = month;
                                columns[1].textContent = payment.toFixed(2);
                                columns[2].textContent = monthlyPrincipal.toFixed(2);
                                columns[3].textContent = monthlyInterest.toFixed(2);
                                columns[4].textContent = totalInterest.toFixed(2);
                                columns[5].textContent = balance.toFixed(2);
                            
                                //append to the table
                                tableBody.appendChild(clone);
                                }
                            
                                //Build out the summary area
                                let labelPrincipal = document.getElementById("totalPrincipal");
                                labelPrincipal.innerHTML = Number(amount).toLocaleString('en-US', {
                                style: 'currency',
                                currency: 'USD'
                                });

                                let labelInterest = document.getElementById("totalInterest");
                                labelInterest.innerHTML = totalInterest.toLocaleString('en-US', {
                                style: 'currency',
                                currency: 'USD'
                                });

                                let paymentdiv = document.getElementById("payment");
                                paymentdiv.innerHTML = payment.toLocaleString('en-US', {
                                style: 'currency',
                                currency: 'USD'
                                });

                                let totalCostDiv = document.getElementById("totalCost");
                                let totalCost = Number(amount) + totalInterest;
                                totalCostDiv.innerHTML = Number(totalCost).toLocaleString('en-US', {
                                style: 'currency',
                                currency: 'USD'
                                });

                            }
                        
                    

Comments to come

Hello World

The function is call to display ...
'Test - Hello World!'