รบกวนค่ะ ติดปัญหาเรื่องปัดจุดทศนิยม จาก 3ตำแหน่งให้เหลือ 2 ตำแหน่งค่ะ

function calculate(){
    binPay = 0;
    binTaxPay = 0;
    for(num = 1 ; num<=17 ; num++){
        if( (returnValue("txtPay"+num) == "") || (returnValue("txtPay"+num) == 0) ){
            document.getElementById("TaxPay"+num).innerHTML = "";
            $("#HTaxPay"+num).val( "" );
        }else{
            if( returnValue("txtRate"+num) > 0 ){
                binTaxPay += Number((returnValue("txtRate"+num)/100 * returnValue("txtPay"+num)).toFixed(3));
                $("#HTaxPay"+num).val( (returnValue("txtRate"+num)/100 * returnValue("txtPay"+num)).toFixed(3) );
                document.getElementById("TaxPay"+num).innerHTML = addCommas( $("#HTaxPay"+num).val() );
            }else if( (returnValue("txtRate"+num) == "") || (returnValue("txtRate"+num) == 0) ){
                document.getElementById("TaxPay"+num).innerHTML = "";
                $("#HTaxPay"+num).val( "" );
            }else if( returnValue("txtRate"+num) < 0 ){
                binTaxPay += Number((returnValue("txtRate"+num) * -1).toFixed(2));
                $("#HTaxPay"+num).val( (returnValue("txtRate"+num) * -1).toFixed(2) );
                document.getElementById("TaxPay"+num).innerHTML = addCommas( $("#HTaxPay"+num).val() );
            }
        }
        binPay += Number((returnValue("txtPay"+num)).toFixed(2));
    }
    binPay = binPay.toFixed(2);
    binTaxPay = binTaxPay.toFixed(2);
    document.getElementById("SumPay").innerHTML = addCommas(binPay);
    document.getElementById("SumTaxPay").innerHTML = addCommas(binTaxPay);
    $("#HSumPay").val( binPay );
    $("#HSumTaxPay").val( binTaxPay );
    num2text(binTaxPay);