Simple Timer

example.js

// create a new Timer
var reloader = new Timer(30000);

// reload the page
reloader.register(window.location.reload.bind(window.location, true));

// reschedule on mouse movement
document.addEventListener("mousemove", reloader.restart.bind(reloader));

// reschedule on keyboard acitivity
document.addEventListener("keydown", reloader.restart.bind(reloader));

timer.js

function Timer(interval) {
  // save the interval
  this.interval = typeof interval == "number" ? interval : 10000;
  
  // save the callbacks
  this.callbacks = [];
  if(typeof interval == "function") {
    this.register.apply(this, Array.prototype.slice.call(arguments, 0));
  } else {
    this.register.apply(this, Array.prototype.slice.call(arguments, 1));
  }
  
  // start the timeout
  this.start();
}

// set the interval
Timer.prototype.setInterval = function(interval) {
  this.restart(interval);
};

// get the interval
Timer.prototype.setInterval = function() {
  return this.interval;
};

// register a callback
Timer.prototype.register = function() {
  this.callbacks = this.callbacks.concat(Array.prototype.slice.call(arguments));
};

// remove a callback
Timer.prototype.remove = function(cb) {
  var i = this.callbacks.indexOf(cb);
  if(~i) this.callbacks.splice(i, 1);
};

// start the timeout
Timer.prototype.start = function(interval) {
  this.interval = typeof interval == "number" ? interval : this.interval;
  this.timeout = setTimeout(this.exec.bind(this), this.interval);
};

// stop the timeout
Timer.prototype.stop = function() {
  clearTimeout(this.timeout);
};

// restart the timeout
Timer.prototype.restart = function(interval) {
  this.stop();
  this.start(interval);
};

// execute the callbacks
Timer.prototype.exec = function() {
  this.callbacks.forEach(function(cb) {
    cb();
  });
  this.start();
};