function input_money(value){
	while ((i=value.indexOf(",")) >= 0) {
		value = value.substring(0,i) + value.substring(i+1,value.length);
	}
	i=parseInt(value);
	return i;
}

function format_money(value) {

	var result = "";
	value += ""; 

	if (value.length > 6)
		result = (value.substring(0, (value.length - 6))) + "," + 
				(value.substring((value.length - 6), (value.length - 3))) + "," + 
				(value.substring((value.length - 3), value.length));
	else{

		if (value.length > 3)
			result = (value.substring(0, (value.length - 3))) + "," + 
					(value.substring((value.length - 3), value.length));

		else 
			result = value;
	}
	return result;
}

function calcTax(incometax){
	var period = incometax.period.options[incometax.period.selectedIndex].value;
 	var salary = incometax.salary.value;
	salary = input_money(salary);
 	var tax;
 	var medicare;

if (isNaN(salary)) {
	window.alert("Please enter value for Salary.");
}
else {

	if (period == "Y"){
		salaryan = salary;
	}
	else if (period == "M"){
		salaryan = salary * 12;
	}
	else if (period == "F"){
		salaryan = salary * 26;
	}
	else {
		salaryan = salary * 52;
	}

	if (salaryan <= 6000){
     tax = 0;
	}
	else if ((salaryan > 6000) && (salaryan < 21600)){
     tax = (salaryan - 6000) * 0.15;
	}
	else if ((salaryan >= 21600) && (salaryan < 63000)){
     tax = ((salaryan - 21600) * 0.3) + 2340;
	}
	else if ((salaryan >= 63000) && (salaryan < 95000)){
     tax = ((salaryan - 63000) * 0.42) + 14760;
	}
	else {
     tax = ((salaryan - 95000) * 0.47) + 28200;
	}
 
	if (salaryan >= 17191){
	medicare = salaryan * 0.015;
	}
	else if ((salaryan >= 15903) && (salaryan <= 17190)){
	medicare = ((salaryan - 15902) * 0.2);
	}
	else {
	medicare = 0;
	}

var total = tax+medicare;
var net = salaryan - total;

tax = Math.round(tax);
medicare = Math.round(medicare);
net = Math.round(net);

incometax.tax.value = format_money(tax);
incometax.medicare.value = format_money(medicare);
incometax.net.value = format_money(net);
incometax.salary.value = format_money(salary)

}
}