var curResult = 0; function calculate() { var c; var t; var r; var startM; var startY; var PrincipleLoanAmount; var pvifa; var amo; PrincipleLoanAmount = parseFloat(document.LoanCalculator.pincipleLoan.value); r = parseFloat(document.LoanCalculator.rate.value); t = parseInt(document.LoanCalculator.year.value); for(var m = 0; m < document.LoanCalculator.monthList.options.length; m++) { if(document.LoanCalculator.monthList.options[m].selected) { startM = parseInt(document.LoanCalculator.monthList.options[m].value); break; } } for(var m = 0; m < document.LoanCalculator.yearList.options.length; m++) { if(document.LoanCalculator.yearList.options[m].selected) { startY = parseInt(document.LoanCalculator.yearList.options[m].value); break; } } for(var m = 0; m < document.LoanCalculator.yesnoList.options.length; m++) { if(document.LoanCalculator.yesnoList.options[m].selected) { amo = parseInt(document.LoanCalculator.yesnoList.options[m].value); break; } } if ( isNaN(PrincipleLoanAmount) || PrincipleLoanAmount<0) alert("Invalid Input: Expected Mortgage Loan Amount (HKD) "); else if (isNaN(r) || r<0) alert("Invalid Input: Interest Rate "); else if (isNaN(t) || t<0) alert("Invalid Input: Repayment period (Year(s)) "); else { r = (r / 100)/12; t = t * 12; c = PrincipleLoanAmount * r / (1 - Math.pow(( 1 + r), -t)); document.LoanCalculator.c.value = formatCurrency(Math.round(c)); curResult = document.LoanCalculator.c.value; if ( amo == 1) { m_obj = new Date(); m_obj.setMonth(startM); m_obj.setYear(startY); AmorizationTable(PrincipleLoanAmount, r, c, t, startM, startY, self.document); } } } function formatCurrency(num) { var isNegative = false; if (num < 0) { isNegative = true; num = num * -1; } num = num.toString().replace(/\$|\,/g,''); if(isNaN(num)) num = "0"; cents = Math.floor((num*100+0.5)%100); num = Math.floor((num*100+0.5)/100).toString(); if(cents < 10) cents = "0" + cents; for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++) num = num.substring(0,num.length-(4*i+3))+num.substring(num.length-(4*i+3)); if (isNegative == true) { num = "-" + num; } return (num + '.' + cents); } function AmorizationTable(PrincipleLoanAmount, r, c, t, months, years, doc) { var year = years; var month = new Array(12); month[0] = "Jan"; month[1] = "Feb"; month[2] = "Mar"; month[3] = "Apr"; month[4] = "May"; month[5] = "June"; month[6] = "July"; month[7] = "Aug"; month[8] = "Sept"; month[9] = "Oct"; month[10] = "Nov"; month[11] = "Dec"; doc.open(); doc.write(""); doc.write("") doc.write(""); doc.write(""); doc.write("
"); doc.write("
"); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); for( var i = 1 ; i<=t; i++ ) { doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); PrincipleLoanAmount = PrincipleLoanAmount - (c - (PrincipleLoanAmount * r)); if (months == 11) { months = 0; year += 1; } else months += 1; doc.write(""); } doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write(""); doc.write("
"); doc.write("Back to Calculator"); doc.write("
Installment Table
Month/Year Mortgage Balance Installment Interest Paid Principal Paid Outstanding Balance
" + month[months] + ' ' + year + "" + '$' + Math.round(PrincipleLoanAmount) + "" + '$' + Math.round(c) + "" + '$' + Math.round(PrincipleLoanAmount * r) + "" + '$' + Math.round(c - (PrincipleLoanAmount * r)) + "" + '$' + Math.round(PrincipleLoanAmount - (c - (PrincipleLoanAmount * r))) + "
For reference only
"); doc.write(" 
"); doc.write("Back to Calculator"); doc.write("
 
"); doc.write("
"); doc.write("
"); doc.write(""); doc.write(""); doc.close(); } function changeResult() { var message = "You are not allow to modify this entry."; alert( message ); self.document.LoanCalculator.c.value = curResult; } function formatCurrency(num) { num = num.toString().replace(/\$|\,/g,''); if(isNaN(num)) num = "0"; sign = (num == (num = Math.abs(num))); num = Math.floor(num*100+0.50000000001); cents = num%100; num = Math.floor(num/100).toString(); if(cents<10) cents = "0" + cents; for (var i = 0; i < Math.floor((num.length-(1+i))/3); i++) num = num.substring(0,num.length-(4*i+3))+','+ num.substring(num.length-(4*i+3)); return (((sign)?'':'-') + '$' + num + '.' + cents); }