Is there a way to make a scrolling "viewport" box in HTML5/CSS?

Consider i have a div with content in it, but i only want to show a part of it. Specifically the part that overlaps with another div. How would I go about making that happen?

I also want to animate my content div so that it's actually scroll开发者_如何转开发ing, whilst the smaller div acts as a "window" or "viewport" to it.

Is this what you are trying to do?

http://jsfiddle.net/27bxx/

The div will scroll as soon as it is loaded

overflow: scroll;

And then just constraint the width/height.