ตัวอย่างการใช้งาน ปฏิทิน ปีพ.ศ. ด้วย jQuery.datepicker

<form id="frmMain">
        Meeting date - En <input type="text" name="dtEn" id="dtEn" /><br />
        Meeting date - Th <input type="text" name="dtTh" id="dtTh" /><br />
        Meeting date - Th2 <input type="text" name="dtTh2" id="dtTh2" /><br />
        <button id="btnShow">Display date</button>
        <div id="result"></div>
    </form>

    <script src="../jquery-3.3.1.js"></script>
    <script src="../jQuery.UI.Combined.1.12.1/Content/Scripts/jquery-ui-1.12.1.js"></script>
    <script src="../lb/jquery-ui-datepicker-th.js"></script>
    <script type="text/javascript">
        $(function () {
            $("#dtEn").datepicker();
            $("#dtTh").datepicker($.datepicker.regional.th);
            $("#dtTh2").datepicker($.extend({}, $.datepicker.regional.th, { dateFormat: "dd/mm/yy" }));

            $("#btnShow").on("click", function (e) {
                e.preventDefault();
                var sOutput = "Meeting date - En: " + $.datepicker.getYMD("#dtEn");
                sOutput += "<br />Meeting date - Th: " + $.datepicker.getYMD("#dtTh");
                sOutput += "<br />Meeting date - Th2: " + $.datepicker.getYMD("#dtTh2");
                $("#result").html(sOutput);
            });
        });

    </script>

<form id="frmMain">
        Meeting date - 1 <input type="text" name="dt1" id="dt1" /><br />
        Meeting date - 2 <input type="text" name="dt2" id="dt2" /><br />
        Meeting date - 3 <input type="text" name="dt3" id="dt3" /><br />
        <button id="btnShow">Display date</button>
        <div id="result"></div>
    </form>

    <script src="../jquery-3.3.1.js"></script>
    <script src="../jQuery.UI.Combined.1.12.1/Content/Scripts/jquery-ui-1.12.1.js"></script>
    <script src="../lb/jquery-ui-datepicker-th.js"></script>
    <script type="text/javascript">

        // กำหนดค่า default ที่นี่ 
        $.datepicker.setDefaults($.extend($.datepicker.regional.th, { dateFormat: "dd/mm/yy" }));

        $(function () {
            $("input[id^='dt']").datepicker();

            $("#btnShow").on("click", function (e) {
                e.preventDefault();
                var sOutput = "Meeting date 1: " + $.datepicker.getYMD("#dt1");
                sOutput += "<br />Meeting date 2: " + $.datepicker.getYMD("#dt2");
                sOutput += "<br />Meeting date 3: " + $.datepicker.getYMD("#dt3");
                $("#result").html(sOutput);
            });
        });
    </script>

// ระบุ ID
var sOutput = "Meeting date 1: " + $.datepicker.getYMD("#dt1");  

// Form Input Element
sOutput += "<br />Meeting date 2: " + $.datepicker.getYMD(frmMain.dt2);

// datapicker data instance
sOutput += "<br />Meeting date 3: " + $.datepicker.getYMD($("#dt3").data("datepicker"));

<form id="frmMain">
        Meeting date - En <input type="text" name="dtEn" id="dtEn" /><br />
        Meeting date - Th <input type="text" name="dtTh" id="dtTh" /><br />
        Meeting date - Th2 <input type="text" name="dtTh2" id="dtTh2" /><br />
        <div id="myCalEn"></div>
        <div id="myCalTh"></div>
        <button id="btnShow">Display date</button>
        <div id="result"></div>
    </form>

    <script src="../jquery-3.3.1.js"></script>
    <script src="../jQuery.UI.Combined.1.12.1/Content/Scripts/jquery-ui-1.12.1.js"></script>
    <script src="../lb/jquery-ui-datepicker-th.js"></script>
    <script type="text/javascript">
        $(function () {
            $("#dtEn").datepicker();
            $("#dtTh").datepicker($.datepicker.regional.th);
            $(frmMain.dtTh2).datepicker($.extend({}, $.datepicker.regional.th, { dateFormat: "dd/mm/yy" }));
            var calEn = $("#myCalEn").datepicker().data("datepicker");
            var calTh = $("#myCalTh").datepicker($.extend({}, $.datepicker.regional.th, {
                changeMonth: false,
                changeYear: false
                })).data("datepicker");

            $("#btnShow").on("click", function (e) {
                e.preventDefault();
                var sOutput = "Meeting date - En: " + $.datepicker.getDate("#dtEn");
                sOutput += "<br />Meeting date - Th: " + $.datepicker.getDate(frmMain.dtTh);
                sOutput += "<br />Meeting date - Th2: " + $.datepicker.getDate(frmMain.dtTh2);
                sOutput += "<br />myCalEn: " + $.datepicker.getDate(calEn);
                sOutput += "<br />myCalTh: " + $.datepicker.getDate(calTh);
                $("#result").html(sOutput);
            });
        });

    </script>