helge@mymath.rocks hmm, this I think I disagree with.
I'm all about valid data, sure. It's annoying when data isn't valid, sure.
I think being accepting of less-than-perfect data is something we can all strive for because it opens the door for so much more.
HTML parsing isn't perfect, it has its lumps (some fairly big ones too), but imagine how much further behind we'd be if syntactically imperfect html led to a blank page.