JSFiddle - React, Tailwind, and code Playground

HTML

<p>Loading...</p>

JavaScript

jQuery(function ($) {
    $(window).bind('beforeunload', function () {
        window.open("", "_savedata", "titlebar=0,width=100,height=100").saveFunction = window.saveFunction;
    });
    
    var store = window.open("", "_savedata");     
    window.saveFunction = store.saveFunction ? store.saveFunction : (function () {
         var lulz = 42
        
         return function () {
           lulz += 1;
           return lulz
         }
        }());
    store.close();
    alert(window.saveFunction());
});