Comment by kstrauser

I tried using XHTML when we were told, loudly and repeatedly, that it was the inevitable future. Thank god it wasn’t.

You should close your tags. It’s good hygiene. It helps IDEs help you. But. Trust me, you do not want the browser enforcing it at runtime, lest your idea of fun is end users getting helpful error messages like an otherwise blank screen saying “Invalid syntax”.

For fun, imagine that various browsers are not 100.00% compatible (“Inconceivable!”), so that it wasn’t possible to write HTML that every browser agreed was completely valid. Now it’s guaranteed that some of your users will get the error page, even when you’re sure your page is valid.

Conceptually, XHTML and its analogs are better. In practice, they’re much, much worse.