JSFiddle - React, Tailwind, and code Playground

JavaScript

function getURLParameter(){}
$(document).ready(function() {
      alert('start');  
        var month = getURLParameter('month') - 1; //-1 cause javascript months start in 0
   var currentYear = getURLParameter('year');
   var defaultDate = new Date(currentYear, month, 1); //Set to first day of the month
  $("#date").datepicker({ defaultDate: defaultDate });
  alert('end');

    });