How do I trap 'enter keypress' after certain presses and disable further typing in atext area?

my textarea needs to be restricted to 16 lines no matter what. I have used the change listener and tried getting the number of 'enter' clicks. But how do i lock the textarea such that, the user cannot type anything further, but can edit what all he has written.

I can disable the textarea but this will not allow editing. Can anyone provide me with the thing i need? Hope the idea is clear.


Regards
Roshan