4 ms·

This is invalid html, p tag can be nested in a p tag.

• Hendrikto 10mo ago
  Even though it arguably should be, according to HTML5 parsing rules, this is not invalid. It is just interpreted differently from what most people would probably expect. I think this is the point of the example, afaiui: The closing tags don’t clarify anything, quite the contrary, actually. They serve only to confuse the reader.