<!--

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 = "";

		}

	}

}



//-->