<!-- hide script from old browsers

function checkNum(input) {

        var oldnum;

        var newnum;

        var ch;



        oldnum = input.value;

        newnum ="";

        for(var i=0; i<oldnum.length; i++) {

                ch = oldnum.charAt(i);

                if(ch != ",") {

                        newnum += ch;

                }

        }

        return parseFloat(newnum);

}





function checkNumPeriods(input) {

        input.value = checkNum(input);

        input.value = parseInt(input.value);

        if(input.value == null ||

         input.value.length == 0 ||

           input.value == "NaN") {

                input.value = "";

        }

        else {

                if(parseFloat(input.value) <= 0) {

                        input.value = "";

                }

        }

        calcMonthly(input.form);
        calcMonthlyCA(input.form);

        input.value = commas_place(input.value);

}

function checkTotal(input) {

        input.value = checkNum(input);

        input.value = parseFloat(input.value);

        if(input.value == null ||

         input.value.length == 0 ||

           input.value == "NaN") {

                input.value = "";

        }

        else {

                if(parseFloat(input.value) < 0) {

                        input.value = "";

                }

        }

        calcMonthly(input.form);
        calcMonthlyCA(input.form);


        input.value = commas_place(input.value);

}



function checkInterest(input) {

        input.value = parseFloat(input.value);

        if(input.value == null ||

         input.value.length == 0 ||

           input.value == "NaN") {

                input.value = "";

        }

        else {

                if(parseFloat(input.value) <= 0 ||

                   parseFloat(input.value) > 100.0) {

                        input.value = "";

                }

        }

        calcMonthly(input.form);
        calcMonthlyCA(input.form);


}


function commas_place(input) {

    var result, len;



    input += "";

    len = input.indexOf(".");

    if(len == -1)
    {

        len = input.length;

        result = "";

    }

    else
    {

        result = input.substring(len, input.length);

    }

    while(len > 3)
    {

        result = input.substring(len-3, len) + result;

        result = "," + result;

        len -= 3;

    }

    result = input.substring(0, len) + result;

    return result;

}



function commas_remove(input) {

        var newnum;

        var ch;



        newnum ="";

        for(var i=0; i<input.length; i++) {

                ch = input.charAt(i);

                if(ch != ",") {

                        newnum += ch;

                }

        }

        return parseFloat(newnum);

}




function calcMonthly() {

        if(document.calculator.interest.value == "" ||

           document.calculator.nper.value == "" ||

           document.calculator.loan.value == "") {

                document.calculator.monthly.value = "";

        }

        else {

                i = commas_remove(document.calculator.interest.value) / 1200;

                n = commas_remove(document.calculator.nper.value) * 12;

                tmp = Math.pow((1.0 + i),n)

                tmp = commas_remove(document.calculator.loan.value) * (i / (1.0 - (1.0 / tmp)))

                tmp = Math.round(tmp*100) / 100;


                document.calculator.monthly.value = commas_place(tmp);

                if(document.calculator.monthly.value == null ||

                 document.calculator.monthly.value.length == 0 ||

                   document.calculator.monthly.value == "NaN") {

                        document.calculator.total.value = "";

                }

        }

}

function calcMonthlyCA() {

        if(document.calculator.interest.value == "" ||

           document.calculator.nper.value == "" ||

           document.calculator.loan.value == "") {

                document.calculator.monthlyCA.value = "";

        }

        else {

                i = commas_remove(document.calculator.interest.value) / 200;

                n = commas_remove(document.calculator.nper.value) * -12;

                tmp = Math.pow((1.0 + i),(1/6)) - 1.0

                tmp = commas_remove(document.calculator.loan.value) * (tmp / (1.0 - (Math.pow((1.0 + tmp),n))))

                tmp = Math.round(tmp*100) / 100;


                document.calculator.monthlyCA.value = commas_place(tmp);

                if(document.calculator.monthlyCA.value == null ||

                 document.calculator.monthlyCA.value.length == 0 ||

                   document.calculator.monthlyCA.value == "NaN") {

                        document.calculator.total.value = "";

                }

        }

}

// end hiding script from old browsers -->