Rich-text editing in chunks

[Jason Stitt <jjstitt wisc edu>]

I'm trying to design a text editor that would allow specific blocks of
text in a document to be edited; in between them would be read-only
structure.  For example, the blocks could be enclosed in visual boxes,
with create/update timestamps attached.  It would be nice to be able to
collapse and expand these boxes.

I think an HTML-editing widget may be the way to go (preferably one with
CSS support.)  Is there a well-developed one available?  And would it
allow me to selectively make certain bits read-only and others
editable?  Or would I have to program a custom widget?

Thanks,

Jason Stitt