将datepicker值输入到html表时出错

Question

我尝试将输入数据输入到表格html中。另一个输入工作正常但我在我的表中调用包含datepicker值的文本框时出错。怎么解决？错误说是这样的（“Object Html InputELement”）。

这是代码：

// JavaScript Document

function AddData() {
    var x = document.getElementById("material").value;
    var y = document.getElementById("kapal").value;
    var letters = '/^[a-zA-Z]+$/';
    if ((parseInt(x) != (x)) && (y == parseInt(y))) {
        alert("Wrong Value Entered");
    } else {
        var rows = "";
        var name = "sadcsad";
        var gender = $('input[name="gender"]').val();
        var tgl = document.getElementById("datepicker").value;
        var nopol = document.getElementById("nopol").value;
        var netto = document.getElementById("netto").value;

        rows += "<tr><td>" + datepicker + "</td><td>" + nopol + "</td><td>" + netto + "</td></tr>";
        $(rows).appendTo("#table_bkk tbody");
    }
}

function ResetForm() {
    document.getElementById("person").reset();
}

<div id="kanan"  class="btn btn-default" style="padding-left:20px" >
    <table id="table_bkk" cellspacing='0' class="js-serial" border="2">
        <thead>
            <tr>
                <th><center>No.</center></th>
                <th><center>Tanggal</center></th>
                <th><center>No.Polisi</center></th>
                <th><center>Berat Material</center></th>

            </tr>

        </thead>
        <tbody>
        </tbody>
        <tr>
                <td width="auto" style="border-right:hidden" align="right">Total Bongkaran</td>
                <td width="auto" style="border-right:hidden" align="left">:</td>
                <td width="auto" style="border-right:hidden">
                <td width="auto">
                <input type="text" id="sts" type="text" name="sensor1" maxlength="10" size=9 disabled="disabled"> </td>
        </tr>
        </table>
      <script>
function incrementValue()
{
    var value = parseInt(document.getElementById('no').value, 10);
    value = isNaN(value) ? 0 : value;
    value++;
    document.getElementById('no').value = value;
}
</script>