// JavaScript Document

function PerformCalc()
{
	var countOfDays = 0;
	if (document.getElementById("tfa_Monday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Tuesday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Wednesday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Thursday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Friday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Saturday").checked) countOfDays++ ;
	if (document.getElementById("tfa_Sunday").checked) countOfDays++ ;

	var dailyMilesRT = document.getElementById("txtDailyMilesRT").value;
	var gasMileage = document.getElementById("txtGasMileage").value;
	
	if (IsNumeric(dailyMilesRT) && IsNumeric(gasMileage))
	{
	
		
 	var daysPerMonth = 22;
        var costPerMileMaint = 0.07;
        var costPerMileTires = 0.007;
        var gasPrice = 3.40;
        var milesPerGallon = gasMileage;
		var mileage = dailyMilesRT;
        var parkingCost = 100;

        var annualOwnership15K = (15.47 * daysPerMonth * 12);
        var annualOwnership10K = annualOwnership15K - (annualOwnership15K * .156);
        var annualOwnership20K = annualOwnership15K + (annualOwnership15K * .168);
        var milesPerMonth = (mileage * daysPerMonth);
        var gallonsPerMonth = (milesPerMonth / milesPerGallon);
        var gasCostPerMonth = (gallonsPerMonth * gasPrice);
        var maintCostPerMonth = (milesPerMonth * costPerMileMaint);
        var tireCostPerMonth = (milesPerMonth * costPerMileTires);
        var operatingCostPerMonth = (gasCostPerMonth + maintCostPerMonth + tireCostPerMonth);
        var monthlyExpense = (operatingCostPerMonth + parkingCost);
        var operatingCostPerMile = (operatingCostPerMonth / milesPerMonth);
        var monthlyCosts = (milesPerMonth * operatingCostPerMile) + parkingCost;
        var annualMiles = (milesPerMonth * 12);
        var annualParkingCost = parkingCost * 12;

        var annualOwnershipCost = annualOwnership15K;

        if (annualMiles >= 20000)
        {

            annualOwnershipCost = annualOwnership20K;
        
        }

        if (annualMiles <= 10000)
        {

            annualOwnershipCost = annualOwnership10K;
        
        }


        var annualCost = (operatingCostPerMile * annualMiles) + annualOwnershipCost + annualParkingCost;
	var savings = (annualCost /365) * (countOfDays * 52);
		
		if (!isNaN(annualCost) && !isNaN(savings))
		{
		
			document.getElementById("txtSavings").value = formatCurrency(savings);
		
		}
		else
		{
		
			document.getElementById("txtSavings").value = "ERROR";
		
		}
		
	}

}

function IsNumeric(input) 
{    

	return (input - 0) == input && input.length > 0; 
	
} 

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);
		
}