Update billing.js

js/billing.js

@@ -100,8 +100,7 @@ function billingUpdater() {
 
 }
 //calenderfunction myFunction() {
-$(document).ready(function () {});
-$(document).ready(function () {
+document.addEventListener('DOMContentLoaded', function () {
     var month = new Array();
     month[0] = "January";
     month[1] = "February";