- What is delegation? (when we hang a handler on a container and check the click on the element inside - yes, they still ask)

- What is LocalStorage and how is it different from Cookies? How to protect a cookie so that it cannot be read by js (HttpOnly flag)?

- What is WebSocket? What is long-polling and how are they different? What problems do they solve?

- ServiceWorker / WebWorker / SharedWorker? What is it? Why? How?

- event.preventDefault() and event.stopPropagation() - why and when?

- What's interesting in the new proposals and what are you looking forward to the most?

- What is a higher-ordered function? (once I was asked an additional question - "can you pass a function to it?" and it was a very strange question!)