JSFiddle - React, Tailwind, and code Playground

by tihg7947

HTML

<input id='StartDate' name='StartDate' value=''>
<input id='EndDate' name='EndDate' value=''>

JavaScript

$("#StartDate").datepicker({
    changeMonth: true,
    changeYear: true,
    dateFormat: "dd-M-yy",
    onSelect: function () {
        autoFillEndDate();
    }
});
$("#EndDate").datepicker({
    changeMonth: true,
    changeYear: true,
    dateFormat: "dd-M-yy"
});

function autoFillEndDate() {
    if ($('#StartDate').val().length !== 0) {

        var offset;
        var offsetType;
        var StartDate = $('#StartDate').datepicker('getDate');
        
        var newDate = StartDate.setMonth(StartDate.getMonth() + 6);
        var EndDT = $.datepicker.formatDate('dd-M-yy', new Date(newDate));

        $('#EndDate').datepicker("setDate", EndDT);
    }
}