phpjs/functions/misc/time_sleep_until.js

php.js offers community built php functions in javascript

function time_sleep_until(timestamp) {
  //  discuss at: http://phpjs.org/functions/time_sleep_until/
  // original by: Brett Zamir (http://brett-zamir.me)
  //        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;
}