Self-closing a <TD /> tag

Question

I came across a code where a developer attempted to close an empty table cell like this <TD /> instead of <td></td>.

Is <td /> valid? When is it appropriate to close a tag like <tag />? What language does it come from originally?

Answer 1

Non-HTML Compatible XHTML (so not if you want to use a text/html content-type or support IE 8 or older).

If an element permits content (e.g., the div element) but an instance of that element has no content (e.g., an empty section), DO NOT use the "minimized" tag syntax (e.g., <div />).

— http://www.w3.org/TR/xhtml-media-types/#C_3