问根据输入值动态更改datepicker中的日期

EN

$(document).ready(function(){
    $('#day').keydown(function (event) {
        if (event.which === 13) {
            var dayval = $("#day").val();
            var monthval = $("#month").val();
            var yearval = $("#year").val();
            var sync = $('#dtpicker').datepicker({
                dateFormat: 'dd-mm-yy'
            });
            var today = new Date();
            var substractday = today - dayval
            var substractmonth = today - monthval
            var substractyear = today - yearval
            $("#dtpicker").val(substractday);
            $("#dtpicker").val(substractmonth);
            $("#dtpicker").val(substractyear);
        }
    });
});

<link href="https://code.jquery.com/ui/1.12.1/themes/base/jquery-ui.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<div>
    <div>
        <input type="text" name="dob" id="dtpicker">
    </div>
    <div>
        <input type="text" name="year" id="year" placeholder="Enter Your Age in Year">
    </div>
    <div>
        <input type="text" name="month" id="month" placeholder="Enter Your Age in Month">
    </div>
    <div>
        <input type="text" name="day" id="day" placeholder="Enter Your Age in Day">
    </div>
</div>