Freeze List Header when reaching top of page

[rprameshwor]

I have a report page with few prompts [ including multiselect and select and search types  that take up good amount of space] and a List.

I am able to freeze the list headers in its initial position [ by using two table rows and blocks inside them , one for list header and one for list body ]. but since the prompts also occupy a significant space in the report ,
the list headers are freezed around the middle of page causing the list area to be small..

Is there someway i could let the list headers scroll until it reaches the top of page  [ so that the prompts are off the page ] but after that Freeze the list headers so that they should stay at the top while the list data gets scrolled.

Any javascript / css or other approach to the solution highly appreciated.

Thanks In Advance ,