<!--


  function Validate(Fields) {
//-------------------------------
    if (Fields.InvoiceNo.value == "") {
      alert("Please enter the Invoice No..")
      Fields.InvoiceNo.focus()
      Fields.InvoiceNo.select()
      return false
    }
    if (IsNumeric(Fields.Payment.value) == false) {
        alert("Payment must be a numeric value and canot be negative. Please re-enter.")
        Fields.Payment.focus()
        Fields.Payment.select()
        return false
      }

      return true;
}


//-------------------------------
  function IsNumeric(strString)
//-------------------------------
   //  check for valid numeric strings	
   {
   var strValidChars = "0123456789.";
   var strChar;
   var blnResult = true;

   if (strString.length == 0) return false;

   //  test strString consists of valid characters listed above
   for (i = 0; i < strString.length && blnResult == true; i++)
      {
      strChar = strString.charAt(i);
      if (strValidChars.indexOf(strChar) == -1)
         {
         blnResult = false;
         }
      }
   return blnResult;
   } 
// -->