Auto Adjust Timer Function, does not 100% guarantee accurate.

autoadjusttimer.js

(function(root) {
  if(!root) root = {};
  var nextID = 0, timers = [];
  root.setAutoAdjustInterval = function(callback, interval, timeKeeperFunc, frameTheshold) {
    if(!timeKeeperFunc || typeof timeKeeperFunc != "function")
      timeKeeperFunc = Date.now;
    if(!frameTheshold || typeof frameTheshold != "number")
      frameTheshold = 1000 / interval;
    var timeDiff,
    thisTS,
    startTS = timeKeeperFunc(),
    lastTS = startTS,
    thisID = nextID++,
    times = 1,
    timeDiffs = [],
    calcInterval = interval,
    fn = function() {
      if(timers.indexOf(thisID) < 0) return;
      thisTS = timeKeeperFunc();
      timeDiff = thisTS - startTS;
      calcInterval = Math.round(interval * interval * times / timeDiff);
      callback();
      setTimeout(fn, calcInterval);
      timeDiffs.push(thisTS - lastTS);
      lastTS = thisTS;
      if(times < frameTheshold) times++;
      else startTS += timeDiffs.shift();
    };
    setTimeout(fn, interval);
    timers.push(thisID);
    return thisID;
  };
  root.clearAutoAdjustInterval = function(id) {
    var index = timers.indexOf(id);
    if(index >= 0)
      timers.splice(index, 1);
  };
})(this);