phpjs/experimental/misc/time_nanosleep.js

php.js offers community built php functions in javascript

function time_nanosleep(seconds, nanosecs) {
  // http://kevin.vanzonneveld.net
  // +   original by: Brett Zamir (http://brett-zamir.me)
  // %        note 1: For study purposes. Current implementation could lock up the user's browser.
  // %        note 1: Consider using setTimeout() instead.
  // %        note 2: Note that the following function's argument, contrary to the reference to
  // %        note 2: nanoseconds, does not start being significant until 1,000,000 nanoseconds (milliseconds),
  // %        note 2: since that is the smallest unit handled by JavaScript's Date function.
  // *     example 1: time_nanosleep(1, 2000000000); // delays for 3 seconds
  // *     returns 1: true

  var start = new Date().getTime();
  while (new Date() < (start + seconds * 1000 + nanosecs / 1000000)) {}
  return true;
}