scrolling drupal block/blocks

I've a website that shows a block on the 'sidebar_first' (I used acquia_marina as a reference theme n changed it as per my needs) region and is at a fixed spot. When the user scrolls down (using the scroll bar in the browser ) I want the block/blocks to scroll down as well. Is there a way do it in drupal using some configuration changes and/or php code? or is javascript the answer for this? If its javascript any onlines references (if any) would be highly apprciated
Thanks