It would also be possible to use chrome for the same. Chrome has a feature where you can specify a parser attribute and make the piece of dynamic JS appear as a file which can then be browsed to and break points set.
the attribute that needs to be set is
//# sourceURL=dynamicScript.js
where dynamicScript.js is the name of the file that should show up in the script file browser.
More information here
Paul Irish also talks about it briefly in his excellent talk on Tooling & The Webapp Development Stack