// calculateMinimumInstallment()
            // -----------------------------------------------------------------------------------------------------
            // Calculates and returns the smallest monthly payment (min EUR 17), including interest.
            // Does not take a stand on whether the credit amount is too low or high.
            // -----------------------------------------------------------------------------------------------------
            // double amount            - credit amount
            // double interest            - reference interest
            // double margin            - margin rate
            // double monthlyFee        - account management fee per month
            function calculateMinimumInstallment(amount, interest, margin, monthlyFee) {
                installment = 17;      // lowest possible monthly payment as the lowest possible credit amount is EUR 200
                
                while (1) {
                    if (installment <= 2 * (amount * (interest+margin) / 1200) + (2 * monthlyFee)) {
                        installment++;
                    }
                    else {
                        break;
                    }
                }
                
                return installment;
            }

            // calculateEstimation()
            // ---------------------------------------------------------------------------------------------------------
            // Calculates the loan period, account management fees, interest, credit expenses, credit price and 
            // actual annual interest based on the monthly payment, price of the product, reference interest, 
            // margin rate and account management fee without instalment-free months. Returns the values
            // in an html table. The monthly payment must include interest.
            // The product price must be between EUR 200 and 10,000.
            // The loan period must be between 6 and 120 months.
            // ---------------------------------------------------------------------------------------------------------
            // double loanAmountMonth    - monthly payment
            // double amount                    - product price
            // double interest                    - reference interest
            // double margin                    - margin rate
            // double monthlyFee             - account management fee per month        
            function calculateEstimation(loanAmountMonth, amount, interest, margin, monthlyFee) {
                loanPeriod = 0;             // loan period, in months
                saldo = amount;                  // outstanding balance, in euros
                totalInterest = 0;                 // total interest, in euros
                transactions = [];                 // instalments for the calculation of actual annual interest
                transactions[0] = amount;   // product price for the calculation of actual annual interest

                if (amount < 200) {
                    return "<table><tr><td>Minimum credit amount is EUR 200&;.</td></tr></table>";
                }
                else if (amount > 10000) {
                    return "<table><tr><td>Maximum credit amount is EUR 10,000&;.</td></tr></table>";
                }
                
                // Monthly payment is lower than interest
                if (loanAmountMonth <= 2 * (saldo * (interest+margin) / 1200) + (2 * monthlyFee)) {
                    return "<table><tr><td>Choose higher monthly payment.</td></tr></table>";
                }
                while (saldo > loanAmountMonth) {                                            
                    interestPaid = saldo * (interest+margin) / 1200;                  // interest per month                
                    installment = loanAmountMonth - monthlyFee - interestPaid;        // proportion of instalment in monthly payment
                    saldo -= installment;                                                            // outstanding balance
                    totalInterest += interestPaid;                                               // interest up to date
                    loanPeriod ++;                                                                     // loan period up to date
                    transactions[loanPeriod] = "-"+loanAmountMonth;              // instalment for the calculation of actual annual interest
                }
                
                interestPaid = saldo * (interest+margin) / 1200;                             // interest of the last month
                totalInterest += interestPaid;                                                           // final total interest
                loanPeriod ++;                                                                                 // final loan period                
                transactions[loanPeriod] = "-"+(saldo+interestPaid+monthlyFee);   // instalment for the calculation of actual annual interest
                

                if (loanPeriod < 6) {
                    return "<table><tr><td>Choose lower monthly payment.</td></tr></table>";
                }
                else if (loanPeriod > 120) {
                    return "<table><tr><td>Choose higher monthly payment.</td></tr></table>";
                }  
var browserName=navigator.appName; 
 if (browserName=="Microsoft Internet Explorer")
 {
 return "<table><tr><td>Laina-aika</td><td>"
                    + loanPeriod +
                    " kk</td></tr><tr><td>Kuukausierä</td><td>"
                    + loanAmountMonth +
                    " &euro;</td></tr><tr><td>Tilinhoitomaksut</td><td>"
                    + loanPeriod * monthlyFee +
                    " &euro;</td></tr><tr><td>Korot yhteensä</td><td>"
                    + totalInterest.toFixed(0) +
                    " &euro;</td></tr><tr><td>Luoton kustannukset yht.</td><td>"
                    + ((loanPeriod * monthlyFee) + totalInterest).toFixed(0) +
                    " &euro;</td></tr><tr><td>Luottohinta</td><td>"
                    + ((loanPeriod * monthlyFee) + totalInterest + amount).toFixed(0) +
                    " &euro;</td></tr><tr><td>Todellinen vuosikorko</td><td>"
                    + calculateActualInterestRate(transactions, interest+margin).toFixed(1) +
                    " %</td></tr></table>";
}else{
//alert(document.getElementById('calc1').value);
//document.getElementById('calc1').innerHTML  = loanPeriod;
//document.getElementById('calc11').innerHTML  = loanPeriod;
//alert(document.getElementById('calc1').value);

}




            }

            // calculateActualInterestRate()
            // ---------------------------------------------------------------------------------------------------------
            // Calculates and returns the actual annual interest without interest-free months.
            // Help function of CalculateEstimation().
            // ---------------------------------------------------------------------------------------------------------
            // array transactions    - product price and instalments, eg [200, -25, -25, -25, -25, -25, -25, -25, -25, -25, -16.23]
            // double interest        - interest                
            function calculateActualInterestRate (transactions, interest) {
                d = 1;
                j = 0;
                x = 1 + interest / 100;
                error = false;
                
                date = new Date();
                year = date.getFullYear();                                                    // current year
                month = date.getMonth();                                                     // current month
                theLastYear = year + parseInt(((transactions.length)/12));  // year of last instalment
                remainderMonths = (transactions.length) % 12;                  // month of last instalment
                if (month + remainderMonths > 12) {
                    theLastYear ++;
                    theLastMonth = (month + remainderMonths) - 12;
                }
                else {
                    theLastMonth = month + remainderMonths;
                }
                
                theLastDate = new Date(theLastYear, theLastMonth, 15);        // date of last instalment
                    
                do {
                    prev_d = d;                        
                    sum1 = 0;
                    sum2 = 0;
                    transactionMonth = month;
                    transactionYear = year;
                    
                    for (k = 0; k < transactions.length; k++) {            
                        transactionDate = new Date(transactionYear, transactionMonth, 15);    // date of this instalment                          
                        days  = Math.abs(theLastDate - transactionDate) / (1000 * 60 * 60 * 24);                        
                        years = days / 365.25;
                        
                        xPowSum1 = Math.pow(x, years);
                        xPowSum2 = Math.pow(x, years-1);                    

                        sum1 += transactions[k] * xPowSum1;
                        sum2 += transactions[k] * years * xPowSum2;
                                
                        if (transactionMonth < 11) {
                            transactionMonth ++;            // month of next instalment
                        }
                        else {
                            transactionMonth = 0;            // month of next instalment
                            transactionYear ++;                // year of next instalment
                        }
                    }
    
                    if (sum2) {
                        d = sum1/sum2;
                        x -= d;
                    } 
                    else {
                        error = true;                
                    }
    
                    j++;                    
                } while (Math.abs(d) >= 0.0001 && j < 100 && Math.abs(d) < Math.abs(prev_d) && sum2 != 0.0 );
        
                if ((j < 100) && !error) {                    
                    return (x - 1) * 100;
                }

                return 0;
            }