A HTML page that computes an OAuth 1.0 signature, showing all the workings so you can debug your own implementation.
http://7digital.github.com/oauth-reference-page
It supports POSTs in the form of application/x-www-form-urlencoded, as well as POSTs of application/xml and application/json using the Authorization header - just put the XML or JSON into the 'body' field and set the 'body encoding' accordingly.
The page is hosted on Github Pages, so be sure to merge your changes into the gh-pages branch to see them.
The JavaScript is generated from the PogoScript files. Once you have installed PogoScript, just:
pogo -cw *.pogo
Tests are written using Zombie.js and mocha.
mocha test/spec.pogo