> the argument to `hasClass` is problematic: it uses selector-syntax and > starts with a dot. this is a mistake that easily results from copy-n- > pasting code. acceptable reactions of jQuery to this would be > responding with something like `null`, `undefined`, or `false`, or > raising an exception for having been passed a bogus argument.
I filed a bug on this, it was pretty easy to repro. http://dev.jquery.com/ticket/3380
