function GetDifference(v)
{

    client_gross = document.calculator.gross.value.replace(",",".");
    client_tax = document.calculator.tax.value.replace(",",".");
    sel_year = document.calculator.year.value;
 
    if (v == 1 && !client_gross && !client_tax)
    {
	return;
    }
    
    if (sel_year == "2006/2007")
    {
        ten_procent = 2150;
        twenty_procent = 33300;
	fix_value = 5035;
	end_procent = 40;
    }
    else if (sel_year == "2005/2006")
    {
        ten_procent = 2090;
        twenty_procent = 30310;
	fix_value = 4895;
	end_procent = 40;
    }
    else if (sel_year == "2004/2005")
    {
        ten_procent = 2020;
        twenty_procent = 29380;
	fix_value = 4745;
	end_procent = 40;
    }
    else if (sel_year == "2003/2004")
    {
        ten_procent = 1920;
        twenty_procent = 27980;
	fix_value = 4615;
	end_procent = 40;
    }
    else if (sel_year == "2002/2003")
    {
        ten_procent = 1920;
        twenty_procent = 27980;
	fix_value = 4615;
	end_procent = 40;
    }
    else if (sel_year == "2001/2002")
    {
        ten_procent = 1880;
        twenty_procent = 27520;
	fix_value = 4535;
	end_procent = 40;
    }
    else if (sel_year == "2000/2001")
    {
        ten_procent = 1520;
        twenty_procent = 26880;
	fix_value = 4385;
	end_procent = 40;
    }
    if (isBlank(client_gross))
    {
        alert("Please enter Gross Pay value");
        document.calculator.gross.value = "";
        document.calculator.gross.focus();
        return;
    }
    if (isBlank(client_tax))
    {
        alert("Please enter Tax value");
        document.calculator.tax.value = "";
        document.calculator.tax.focus();
        return;
    }

    gross_value = parseFloat(client_gross);
    tax_value = parseFloat(client_tax);
    
    taxable = gross_value - fix_value;
    total_tax = 0;
    
    if (taxable > 0)
    {
	if (taxable <= ten_procent)
	{
	    total_tax = taxable*0.1;
	}
	else
	{
	    total_tax += ten_procent*0.1;
	    taxable -= ten_procent;
	    if (taxable <= twenty_procent)
	    {
		total_tax += taxable*0.22;
	    }
	    else
	    {
		total_tax += twenty_procent*0.22;
		taxable -= twenty_procent;
		total_tax += taxable*end_procent/100;
	    }
	}
    }
    if (total_tax > tax_value)
    {
	document.calculator.refund.value = 0;
    }
    else if (total_tax <= tax_value)
    {
	refund_value = parseInt(tax_value) - parseInt(total_tax);
	document.calculator.refund.value = refund_value;
    }
}

function isBlank(val)
{
    if(val==null)
    {
        return true;
    }
    for(var i=0;i<val.length;i++)
    {
        if ((val.charAt(i)!=' ')&&(val.charAt(i)!="\t")&&(val.charAt(i)!="\n")&&(val.charAt(i)!="\r"))
        {
            return false;
        }
    }
    return true;
}

function GetSubmit()
{
    if (document.calculator.refund.value != 0)
    {
	document.calculator.submit();
    }
}