Is this open book? I can walk a DOM in many ways. With my eyes closed, I could hack something using `childNodes` and `nextSibling`, but the best way would be the the TreeWalker class, which I have previously used, though I couldn't write a working implementation on a whiteboard without briefly consulting MDN for a refresher. If you're just filtering candidates based on if they've memorized the ever-growing web standard, you're going to lose a lot of good candidates.