JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.4/themes/ui-lightness/jquery-ui.css">

JavaScript

(function() {
    var _old_alert = window.alert;
    window.alert = function() {
        // run some code when the alert pops up
        document.body.innerHTML += "<br>alerting";
        _old_alert.apply(window,arguments);
        document.body.innerHTML += "<br>done alerting<br>";
    };
})();


alert('hey');
alert('you');
alert('there');