I’m happy to announce my first Firefox extension called Library Detector. Similar to a greasemonkey script I published to the jQuery mailing lists a couple months ago that showed if jQuery is running (which proved to be pretty useful to extend the Sites using jQuery page), the library detector is able to detect multiple libraries, currently including the following:

If one of these is found on the current page, it displays their favicon in the statusbar, and if you hover it, a tooltip will show with additional information (In most cases the version of the library, in the case of jQuery UI the plugins being used, and for Dojo if Dijit is being used).

Of course, there’s one catch in some libraries: If the developer renamed the scope of the Library (i.e. window.dojo) to something entirely different, the test fails (however, usually that’s not the case).

So, if you want to know what websites use your favorite library (or which do not), go ahead and grab the Library Detector from its download page.

Additionally, I’d love to see feedback, and if you think there’s a library missing, or if you have an idea how to improve a test / show additional information, please leave me a comment.