JSFiddle - React, Tailwind, and code Playground

JavaScript

function sleep(milliseconds) {
  var start = new Date().getTime();
  for (var i = 0; i < 1e7; i++) {
    if ((new Date().getTime() - start) > milliseconds){
      break;
    }
  }
}

alert('hello');
sleep(5000); // wait 5 seconds
alert('world');