You can view HTML as a weird, quirky version of XHTML if you want. But XHTML lost the war. Browsers are HTML5 engines, not XHTML engines.

And if you're writing HTML, the browser considers <br/> to just be a weird way to write <br>. The slash is non-significant. So confusingly <script /> is not equivalent to <script></script>.

The problem I have with self-closing tags is that I've met so many web developers throughout my career who think that browsers understand self closing tags. I used to be one of them! And that will almost always, but not always work out fine:

- React / JSX supports self closing tags. So do a lot of other web frameworks.

- Void elements ignore the /. (And you don't need to close void tags anyway). So you can write input, img, br, etc tags however you want.

- HTML5 will auto-insert missing closing tags when it needs them. Eg, <div><span /></div> will render as you expect because the browser will automatically close the span when you close the div. (!)

But it'll confuse you in weird ways. Like <script src="..." /> - which the browser dangerously interprets as an open script tag. Subsequent text is interpreted as javascript!

I think its good practice to be clear in all source files whether you're writing XHTML (eg in .jsx) or writing real, god fearing HTML. And then never use self closing tags in HTML. Sooner or later, someone will think they matter and you'll get bugs.

> Void elements lacking the need for a closing tag or closing slash is one of the weird edge cases in HTML. While it's not in the HTML spec

It's explicitly in the HTML5 spec as allowed, but not required.