Realtime code editor with color coding

Realtime code editor with color coding

We are developing a web based code editor for HTML/CSS/Javascript and want
that as the user types the code in the editor, it should color it the
syntax, like it is usually done in desktop editors like notepad ++.
For example, we want to something line what this library from google code
does http://google-code-prettify.googlecode.com/svn/trunk/README.html
However, this applies the color coding to static text on the web page. I
am looking for a solution, where as the user is typing in the text area,
the code gets color codes along the way. Anyone aware of any such JS or
other library or technique to do this ?
Thanks for your help. kabir