JavaScript Mortgage CalculatorThis page uses a form to create a mortgage calculator, and then uses JavaScript (displayed below the calculator) to perform the actual calculations.Here's how you use this form:
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<SCRIPT LANGUAGE="JavaScript"> <!-- function checkForZero(field) { if (field.value == 0 || field.value.length == 0) { alert ("This field can't be 0!"); field.focus(); } else calculatePayment(field.form); } function cmdCalc_Click(form) { if (form.price.value == 0 || form.price.value.length == 0) { alert ("The Price field can't be 0!"); form.price.focus(); } else if (form.ir.value == 0 || form.ir.value.length == 0) { alert ("The Interest Rate field can't be 0!"); form.ir.focus(); } else if (form.term.value == 0 || form.term.value.length == 0) { alert ("The Term field can't be 0!"); form.term.focus(); } else calculatePayment(form); } function calculatePayment(form) { princ = form.price.value - form.dp.value; intRate = (form.ir.value/100) / 12; months = form.term.value * 12; form.pmt.value = Math.floor((princ*intRate)/(1-Math.pow(1+intRate,(-1*months)))*100)/100; form.principle.value = princ; form.payments.value = months; } //--> </SCRIPT>