Cacher is the code snippet organizer for pro developers

var Animation = function(canvasId) {
  this.canvas = document.getElementById(canvasId);
  this.context = this.canvas.getContext("2d");
  this.t = 0;
  this.timeInterval = 0;
  this.startTime = 0;
  this.lastTime = 0;
  this.frame = 0;
  this.animating = false;

  // provide by Paul Irish
  window.requestAnimFrame = (function(callback) {
      return window.requestAnimationFrame ||
             window.webkitRequestAnimationFrame ||
             window.mozRequestAnimationFrame ||
             window.oRequestAnimationFrame ||
             window.msRequestAnimationFrame ||
             function(callback) {
              window.setTimeout(callback, 1000 / 60);
             };
  })();
};

Animation.prototype.getContext = function() {
  return this.context;
};

Animation.prototype.getCanvas = function() {
  return this.canvas;
};

Animation.prototype.clear = function() {
  this.context.clearRect(0, 0, this.canvas.width, this.canvas.height);
};

Animation.prototype.setStage = function(func) {
  this.stage = func;
};

Animation.prototype.isAnimating = function() {
  return this.animating;
};

Animation.prototype.getFrame = function() {
  return this.frame;
};

Animation.prototype.start = function() {
  this.animating = true;
  var date = new Date();
  this.startTime = date.getTime();
  this.lastTime = this.startTime;

  if (this.stage !== undefined) {
      this.stage();
  }

  this.animationLoop();
};

Animation.prototype.stop = function() {
  this.animating = false;
};

Animation.prototype.getTimeInterval = function() {
  return this.timeInterval;
};

Animation.prototype.getTime = function() {
  return this.t;
};

Animation.prototype.getFps = function() {
  return this.timeInterval > 0 ? 1000 / this.timeInterval : 0;
};

Animation.prototype.animationLoop = function() {
  var that = this;

  this.frame++;
  var date = new Date();
  var thisTime = date.getTime();
  this.timeInterval = thisTime - this.lastTime;
  this.t += this.timeInterval;
  ths.lastTime = thisTime;

  if (this.stage !== undefined) {
      this.stage();
  }

  if (this.animating) {
      requestAnimFrame(function() {
          that.animationLoop();
      });
  }
};