[mikeya]

You'd hope that before they bring you in they know that you know basic front end stuff. To be honest most front end tech is simply memorization of standards and idiosyncrasies between browsers. Anyone can go through and figure this stuff out via a simple google search. On the other hand taking say data from a Ajax call and sorting it or filtering it with custom logic takes some creative problem solving to do it gracefully.

Interviewees always forget to figure out why they interviewer and company is asking these questions or requiring particular knowledge. Next time just ask them!