SCROLL = function(obj, attr) 
{
  var interval;
  var offset = {'top': obj.offsetTop || 0,'height': obj.offsetHeight || 0 };
  
  this.start = function(amount) 
  {
	  /* Default setzen */
	  attr.top = attr.top || 0;
	  attr.width = attr.width || "auto";
	  attr.height = attr.height || "auto";
	  
	  interval = setInterval(function(){move(amount);},attr.time);
  };


function move(amount) 
{
	/* Werte refreshen */
    attr.top += amount;
    attr.height += amount;
    offset.top -= amount;
    
    /* Grenze überschritten? */
    if (attr.top < 0 || attr.height > offset.height) 
    {
        attr.top -= amount;
        attr.height -= amount;
        offset.top += amount;
        return;
    }
    
    /* Object bewegen */
    obj.style.clip = "rect(" + attr.top + "px " + attr.width + "px " + attr.height + "px 0)";
    obj.style.top = offset.top + "px"; 
  }
	
	this.stop = function() 
	{
		if (interval)
		{
			clearInterval(interval);
		}
	}

}