docs: function (props, duration) {
  		this.each(function () {
  			if (this._step == null) {
  				this._step = {};
  				this.bind('EnterFrame', tweenEnterFrame);
  				this.bind('RemoveComponent', function (c) {
  					if (c == 'Tween') {
  						this.unbind('EnterFrame', tweenEnterFrame);
  					}
  				});
  			}
  
  			for (var prop in props) {
  				this._step[prop] = { prop: props[prop], val: (props[prop] - this[prop]) / duration, rem: duration };
  				this._numProps++;
  			}
  		});
  		return this;
  	}