With animating certain parts UI, one comes to appreciate el.getScrollSize() in mooTools pretty fast.
jQuery is missing this function. How it looks in mooTools.
2432 getScrollSize: function(){
2433 var doc = getCompatElement(this), min = this.getSize();
2434 return {x: Math.max(doc.scrollWidth, min.x), y: Math.max(doc.scrollHeight, min.y)};
2435 },
There is a plugin for jQuery that does enable different sizing patterns. I would think it to be essential since javascript is enabling transition active web apps from Flash to HTML5.