JSFiddle - React, Tailwind, and code Playground

HTML

<h1>Date Picker</h1>

<form class="date-picker">
    <label>full date</label>
    
    <input type="text" class="full_date" value="" />
    <input type='hidden' id='hiddentest' />
        <label>Year</label>
    <input type="text" id='idYear' class="month-year"/>
    Month <input type="text" id='month' />
    Day <input type="text" id='day' />
</form>

CSS

label, input{
    display:block;
}
.ui-datepicker .ui-widget-content {
    background: #999 none;
}

JavaScript

$( "#hiddentest" ).datepicker({
		  showOn: "button",
	      buttonImage: "/images/calendar.gif",
	      onSelect: function (dateText, picker) {
              var dateObject = $(this).datepicker("getDate");
                $("#idYear").val(dateObject.getFullYear());
              $("#month").val(dateObject.getUTCMonth()+1);
	          $("#day").val(dateObject.getUTCDate());
              alert($("#hiddentest").val();
              
	      },
	      buttonImageOnly: true,
	      altField: "#month",
	      altFormat: "mm",
	      dateFormat: "mm/dd/yy"

	});