Code Guide by @mdo
codeguide.co
codeguide.co
This kills the XML parser. Yes, I know, you should use a real HTML parser like BeautifulSoup if you can. But sometimes you don't have one available, or you're working with legacy tools.
More importantly, if you're looking through the code and you don't know what tags are self-closing, you can't instantly tell whether something's a syntax error or not. Off hand, do you know which of the SVG tags are self-closing, vs. those that permit optional but rarely-used contents? [0] What about the embed tag? If you make a mistake in rattling off that list, then you cannot claim that you can read through an arbitrary @mdo-compliant document and know with certainty whether there is or is not a syntax error. And I'd bet that many talented frontend developers would make a mistake.
It's an extra character that makes your HTML parse-able by a person or program that isn't a geek (or the programmatic equivalent thereof) who's read the HTML spec. And that's well worth the pinky-press.
I came to say this, so I'll second you instead. Syntax is less cognitive load than remembering what element does what - and in reading code, if I don't see a closing marker I'll go looking for the closing tag before thinking about the tag.