var digit = /^\d*\.?\d+$/;
function report_digit_error()
{
  alert("請確定欄位是否輸入正確(請輸入正確數字格式)");
}
function trialing_function() {
  var credit_amount = 0;
  var credit_ratio = 0;
  var credit_year = 0;
  var formobj = document.getElementsByName("calform");

  credit_amount = document.getElementsByName("creditAmt")[0].value;
  if(!digit.test(credit_amount))
  {
    report_digit_error();
    return false;
  }
  credit_ratio = document.getElementsByName("creditRatio")[0].value;
  if(!digit.test(credit_ratio))
  {
    report_digit_error();
    return false;
  }
  credit_year = document.getElementsByName("creditYear")[0].value;
  if(!digit.test(credit_year))
  {
    report_digit_error();
    return false;
  }

  credit_amount = credit_amount * 10000;
  credit_ratio = credit_ratio/12/100;
  //credit_year = credit_year;

  var month_pay = credit_amount*credit_ratio*Math.pow(1+credit_ratio, credit_year*12)/(Math.pow(1+credit_ratio, credit_year*12)-1);
  var year_pay = month_pay*12;
  var total_pay = year_pay*credit_year;

  var total_pay = Math.round(total_pay);
  var year_pay = Math.round(year_pay);
  var month_pay = Math.round(month_pay);

  //document.getElementsByName("totalpay")[0].value = total_pay;
  //document.getElementsByName("yearpay")[0].value = year_pay;
  var strMonth_pay = ((month_pay + "").length % 3 == 0?(month_pay + "").substr(0, 3):(month_pay + "").substr(0, (month_pay + "").length % 3));

  for (i = 0; i < ((month_pay + "").length % 3 == 0?(month_pay + "").length / 3 - 1:Math.floor((month_pay + "").length / 3)); i++) {
    strMonth_pay = strMonth_pay + "," + (month_pay + "").substr(((month_pay + "").length % 3 == 0?3:(month_pay + "").length % 3) + 3 * i, 3);
  }

  document.getElementsByName("monthpay")[0].value = strMonth_pay;

  //if (digit.test(credit_amount))
  //	alert("+"+credit_amount);
  //else
  //	alert("-"+credit_amount);
}