let mortgageSteps = “”; const currencySymbol = “$”, fixedCurrency = “USD”; function calculateMortgage(){ mortgageSteps=””; const loanAmount=parseFloat(document.getElementById(“loanAmount”).value); const interestRate=parseFloat(document.getElementById(“interestRate”).value)/100; const loanTerm=parseInt(document.getElementById(“loanTerm”).value); const extraPayment=parseFloat(document.getElementById(“extraPayment”).value); if(isNaN(loanAmount)||isNaN(interestRate)||isNaN(loanTerm)||isNaN(extraPayment)||loanAmount<=0||interestRate<=0||loanTerm<=0){ alert("Please enter valid positive values for all fields."); return; } const monthlyRate = interestRate / 12; const numberOfPayments = loanTerm * 12; const originalPayment = (loanAmount * monthlyRate) / (1 – Math.pow(1 + monthlyRate, -numberOfPayments)); const newLoanAmount = loanAmount – extraPayment * numberOfPayments; const totalInterestSaved = (originalPayment * numberOfPayments – newLoanAmount) * (interestRate / 12); document.getElementById("monthlyPayment").value = formatCurrency(originalPayment); document.getElementById("totalInterest").value = formatCurrency(totalInterestSaved); mortgageSteps += `Inputs:
Loan Amount: ${formatCurrency(loanAmount)}
Interest Rate: ${(interestRate * 100).toFixed(2)}%
Loan Term: ${loanTerm} years
Extra Payment: ${formatCurrency(extraPayment)}

`; mortgageSteps += `Formulas:
Original Payment = Loan Amount × Interest Rate ÷ (1 – (1 + Interest Rate) ^ -Loan Term)
Total Interest Saved = (Original Payment × Loan Term – New Loan Amount) × Interest Rate ÷ 12

`; mortgageSteps += `Results:
Original Monthly Payment: ${formatCurrency(originalPayment)}
Total Interest Saved: ${formatCurrency(totalInterestSaved)}
`; if(document.getElementById(“calculationStepsMortgage”).style.display===”block”){ document.getElementById(“calculationStepsMortgage”).innerHTML = mortgageSteps; } } function resetMortgage(){ document.querySelectorAll(“#calculator input”).forEach(el=>el.value=””); mortgageSteps=””; document.getElementById(“calculationStepsMortgage”).innerHTML=”

Not calculated yet.

“; } function toggleMortgageSteps(){ const s=document.getElementById(“calculationStepsMortgage”); const a=document.getElementById(“toggleArrowMortgage”); if(s.style.display===”none”||s.style.display===””){ s.style.display=”block”;a.style.transform=”rotate(180deg)”; s.innerHTML=mortgageSteps||”

Not calculated yet.

“; }else{s.style.display=”none”;a.style.transform=”rotate(0deg)”;} } function formatCurrency(n){return currencySymbol+n.toFixed(2)+” “+fixedCurrency;}