Fast lookup in drop down menu using javascript

It’s not strictly a rails question. It’s more of a javascript question.

I have a huge drown down in the app. If the user presses ‘R’ the the
user is taken to items starting with ‘R’. But if the next key pressed
is ‘a’ then the user is taken to items starting with ‘a’. However the
app should take the user to the items starting with ‘Ra’.

Is there any javascript solution that could be used here.

It can’t be an auto complete. It must be a drop down.

Thanks

http://www.codeproject.com/jscript/autosearch.asp?df=100&forumid=14946&exp=0&select=646883

The solution proposed in the article doesn’t work for firefox 1.5 but
it does work for IE6.0 . Both the browsers were running on win xp.

Thanks.