accurateInterval() is a dop in replacement for setInterval() that does not drift over long periods of time.

accurate_interval.coffee

# Accurate Interval, guaranteed not to drift!
# (Though each call can still be a few milliseconds late)
window.accurateInterval = (time, fn) ->
  
  # This value is the next time the the timer should fire.
  nextAt = new Date().getTime() + time
  
  # Hold a reference to the timer ID so it can be canceled.
  timeout = null
  
  # Allow arguments to be passed in in either order.
  if typeof time is 'function'
    [fn, time] = [time, fn]
  
  # Create a function that wraps our function to run.  This is responsible for
  # scheduling the next call and aborting when canceled.
  wrapper = ->
    nextAt += time
    timeout = setTimeout wrapper, nextAt - new Date().getTime()
    fn()
  
  # Clear the next call when canceled.
  cancel = -> clearTimeout timeout
  
  # Schedule the first call.
  setTimeout wrapper, nextAt - new Date().getTime()
  
  # Return the wrapper function so cancel() can later be called on it.
  return { cancel }

accurate_interval.js

window.accurateInterval = function(time, fn) {
  var cancel, nextAt, timeout, wrapper, _ref;
  nextAt = new Date().getTime() + time;
  timeout = null;
  if (typeof time === 'function') _ref = [time, fn], fn = _ref[0], time = _ref[1];
  wrapper = function() {
    nextAt += time;
    timeout = setTimeout(wrapper, nextAt - new Date().getTime());
    return fn();
  };
  cancel = function() {
    return clearTimeout(timeout);
  };
  setTimeout(wrapper, nextAt - new Date().getTime());
  return {
    cancel: cancel
  };
};

accurate_interval_usage.js

// Use like setTimeout
var timer = accurateInterval(function() {
  console.log('message you will see every second!');
}, 1000);

// Or provide the time first and callback second (much nicer in coffee script)
var timer = accurateInterval(1000, function() {
  console.log('message you will see every second!');
});

// Cancel the interval later by simply calling the cancel method on the returned object.
timer.cancel();

mit.license

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Thanks. I'll test it, because i noticed that setInterval often works not correct.