I want is any of the model value is blank the save msg should not execute, how can I do ?

<script type="text/javascript">
    $(document).ready(function () {



        $("#btnSave").click(function () {
            var empObj = {
                SERIALNO: $('#txtSerialNo').val(),
                CARDSERIALNO: $('#txtCardSNO').val(),
                FAULTCODE1: $('#txtFaultcode').val(),
                DATE_RECEIVED: $('#txtDateReceived').val(),
                PONO: $('#txtPONO').val(),
                CARDPARTNO: $('#txtCardPartNo').val(),

            };

         if (!$("#myform").valid())
            {
            return false;
            }

            $.ajax({
                url: "/Scanning/Postprescaning",
                data: JSON.stringify(empObj),
                type: "POST",
                contentType: "application/json;charset=utf-8",




         success: function (result,data)
            {
             alert("DATA SAVED !!");
                },
                error: function (errormessage) {
                    alert(errormessage.responseText);
                }

            });
        });
    });
        </script>

<script type="text/javascript">
    $(document).ready(function () {



        $("#btnSave").click(function () {
            var empObj = {
                SERIALNO: $('#txtSerialNo').val(),
                CARDSERIALNO: $('#txtCardSNO').val(),
                FAULTCODE1: $('#txtFaultcode').val(),
                DATE_RECEIVED: $('#txtDateReceived').val(),
                PONO: $('#txtPONO').val(),
                CARDPARTNO: $('#txtCardPartNo').val(),

            };

         if (!$("#myform").valid())
            {
            return false;
            }

            $.ajax({
                url: "/Scanning/Postprescaning",
                data: JSON.stringify(empObj),
                type: "POST",
                contentType: "application/json;charset=utf-8",




         success: function (result,data)
            {
             alert("DATA SAVED !!");
                },
                error: function (errormessage) {
                    alert(errormessage.responseText);
                }

            });
        });
    });
        </script>