Does anyone know of a web browser that will let you edit TEXTAREA fields using an external editor?

I am writing a book using wikilatex (http://wikilatex.sf.net), which uses a WIKI-type web interface. This is great for backing up the work and breaking it down into manageable chunks, but suffers from one problem; I have previously written long works under emacs and I don't like not having familiar keyboard shortcuts (ESC,Backspace to delete the last word, ctrl+r to regex-isearch, etc.).

Can anyone recommend a browser or browser plugin to let me edit a textarea in a (preferably embedded) emacs session?

If you are using editing a Wiki and using Firefox you might want to take a look at
Wikipedia Extension http://wikipedia.mozdev.org/

I took a look at the Wikipedia extension, and it looks very good for marking up text like a Wiki.

Unfortunately, WikiLaTeX uses a LaTeX type mark-up rather than a conventional Wiki-type one (it being a LaTeX editor). (The joys of trying to write your own word processor…)

The main problem (and I find this in Wikis too) is that when a page gets long you need to search through it for a particular word or phrase — for example, to fix a spelling mistake. Currently the only way to do that is to scroll through it and skim it by eye, which can take much longer than a quick i-search in emacs. Firefox won't even let you use the find dialog to search inside a text area. And, good though it is, I don't think that Wikipedia extension addresses this problem.

What about "EmacsWiki gives you quick access to a hypertext "wiki" system for storing and navigating information from within Emacs. The wiki pages are normal files, and can contain wiki markup which can be published to HTML and TeX or used entirely within Emacs."
http://freshmeat.net/projects/emacswiki/