JSFiddle - React, Tailwind, and code Playground

by John Schulz

HTML

<button type="button" id="show">Show message</button>
<button type="button" id="hide">Hide message</button>
<button type="button" id="refresh">Refresh the page</button>

JavaScript

var app = {};
onbeforeunload = function() {
    if (app.some_test) return "Here's your message";
}

document.getElementById('show').addEventListener('click', function(e) {
    app.some_test = true;
}, false);

document.getElementById('hide').addEventListener('click', function(e) {
    app.some_test = false;
}, false);

document.getElementById('refresh').addEventListener('click', function() {
    document.location.reload();
}, false);