I'm at a total loss here. I believe I'm right in thinking there is no longer any JS API for twitter which just sucks hugely.
However I realise looking at this I could just use ajax and react to the responses from this:
https://dev.twitter.com/rest/reference/post/statuses/update
OAuth Signature Generator
Example Request POST https://api.twitter.com/1.1/statuses/update.json?status=Maybe%20he%27ll%20finally%20find%20his%20keys.%20%23peterfalk
However when I post to that url I get the following:
{"errors":[{"code":215,"message":"Bad Authentication data."}]}