Question

This cool article briefly discusses no-content style elements. Particularities include that they don’t have closing brackets, and :before: and :after cannot be used on them. Examples include hr and br.

Where can I find an exhaustive list of such elements?

Answer 1

These elements are commonly known as empty elements, i.e. they can’t have any content, which is why :before and :after can’t be used on them:

Some HTML element types have no content. For example, the line break element BR has no content; its only role is to terminate a line of text. Such empty elements never have end tags. The document type definition and the text of the specification indicate whether an element type is empty (has no content) or, if it can have content, what is considered legal content.

You can find a whole list of them in this table.

In the HTML5 drafts, they are known as void elements. Here’s the list:

Void elements
area, base, br, col, command, embed, hr, img, input, keygen, link, meta, param, source, track, wbr