Delay, sleep, pause, wait etc in JavaScript

This article looks into ways to simulate delay, sleep, pause, and wait in JavaScript/jQuery. I’ve briefly looked into this topic before for locking a web page on timer.

PHP has a sleep() function but JavaScript doesn’t as such. jQuery offers us both setTimeout which is similar to run a block of code after a specific time period. Well, you might say this is because it’s useless. But for simulating heavy processing and for misc performance measurements, it could be useful. So here’s how you can go about creating a sleep() in JavaScript, just a little code snippet I found somewhere.

Example of sleep function in js

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


Sleep for 1 second (1000 milliseconds).

console.log(new Date());
console.log(new Date());


Great project – essentially converting PHP function logic to JavaScript. I saw they have converted PHP’s time_sleep_until into a JavaScript function below.

function time_sleep_until (timestamp) {
  // +   original by: Brett Zamir (
  // %          note: For study purposes. Current implementation could lock up the user's browser.
  // %          note: Expects a timestamp in seconds, so DO NOT pass in a JavaScript timestamp which are in milliseconds (e.g., new Date()) or otherwise the function will lock up the browser 1000 times longer than probably intended.
  // %          note: Consider using setTimeout() instead.
  // *     example 1: time_sleep_until(1233146501) // delays until the time indicated by the given timestamp is reached
  // *     returns 1: true
  while (new Date() < timestamp * 1000) {}
  return true;

time_sleep_until(1233146501) // delays until the time indicated by the given timestamp is reached

Maybe a Chained delay() function?

- trigger function after x milliseconds $("#myElement").delay(2000).trigger("click");

Read more: jQuery: Delay execution of any function

Or a setTimeout()…

var dotCounter = 0;
(function addDot() {
  setTimeout(function() {
    if (dotCounter++ < 10) {
  }, 1000);

Read more: John Resig on How JavaScript Timers Work