There is a jQuery- and a Prototype-version. How about a dojo-version?
Dojo currently has something called FilteringSelect: http://livedocs.dojotoolkit.org/dijit/form/FilteringSelect which is not nearly as good as Chosen.
here's my attempt to port it to dojo:
Thanks for sharing @vafada. I'm all for people creating a forked Dojo version, but I'm not super interested in specifically supporting it in the main Chosen repo. I'm much more excited about the possibility of a version of Chosen that has zero framework dependencies.