Include the WorkerConsole.js script at the top of your HTML files and
your Web Worker threads should be able to use console.log() to generate
debugging output. This is just at the proof-of-concept stage, however,
and has not been carefully tested.  See the comment at the top of
WorkerConsole.js.  Only works in browsers that support MessageChannel
(this excludes Firefox 4).

See testpage.html and tests/testworker.js for the simplest possible use of 
WorkerConsole.js