JSFiddle - React, Tailwind, and code Playground

JavaScript

window.onbeforeunload = function() {
    return 'You have unsaved changes!';
}

/* $(window).on("beforeunload", function() {
    $.ajax("someURL", {
        async: false,
        data: "test",
        success: function(event) {
             console.log("Ajax request executed");
        }
    });
    return "This is a jQuery version";
}); */