JSFiddle - React, Tailwind, and code Playground

JavaScript

var timeStart = new Date().getTime();
setTimeout(test, 3000); //<-- timeout should be 100

function test() {
    var timeAfter100MS = new Date().getTime();
    $('body').append('Timeout Fired at: <br>' + (timeAfter100MS - timeStart) + 'ms<br> (should be ~3000, but it did not take the blocked time into account.)');
}

function block() {
    for (var i = 0; i < 100000000; i++) {};
}
block();
block();
block();

var timeEnd = new Date().getTime();
$('body').append('Page was blocked(running importaint code :)) for:<br>' + (timeEnd - timeStart) + 'ms<br>');