Rails - Nov 2006 - looking for a del.icio.us like function

hey all,
I use tags in my page and I have a page with a list of tags. I would
like that when the user click on a tag in the list of tags, the tag
gets displayed in a text box and when the user click back on that same
tag it disappear from the text box.

any idea how to do that?

thanx in advance

Pat