Different things work for different people, personally white boarding is my favorite. I think the best would be to offer the candidate options. Let them come in for the culture fit portion of the interview, at the end present them a problem and let them choose if they prefer white boarding, pair programming, or take home and submit by the end of the day.

I think you can just iterate over the text nodes and see if you stumble upon every letter you're looking for in the right order, it would work for any kind of randomly added text.

It's a way to preemptively send assets to the client before they request them.

Pretty much the same effect is granted to any HTTP version by simply including stylesheets or scripts verbatim into the HTML.

That's anything but "simple" - you might want to reuse those stylesheets/scripts on other pages as well, for example; if you inline them into HTML, you're now wasting far more bandwidth, as you're unconditionally pushing them with every HTML response.