The help does not keep its promise, the site generates incorrect (X)HTML code

Question

The help does not keep its promise, the site generates incorrect (X)HTML code.

The help says that writing --- generates a horizontal rule <hr/>.

However, when I write ---, the site generates <hr> ugly and unclosed !

Instead, the site has to generate the expected <hr/>.

By the way, in the help, a space is missing between “horizontal rule” and “<hr/>”.

By the way, there is no way to find this editing help from the link “help” at the top right. This is a flaw in the flow (!).

Thank you for improving that.

Answer 1

There is nothing incorrect about <hr> in HTML. It would, indeed, be invalid XHTML, but this site does not output XHTML; nor does it claim to.

Answer 2

To put it in more correct technical terms than TRiG:

6: Then, if the element is one of the void elements, or if the element is a foreign element, then there may be a single U+002F SOLIDUS character (/). This character has no effect on void elements, but on foreign elements it marks the start tag as self-closing.

(Source: http://dev.w3.org/html5/spec-author-view/syntax.html#syntax-start-tag)

And foreign elements are:

Elements from the MathML namespace and the SVG namespace.

(Source: http://www.w3.org/html/wg/drafts/html/master/single-page.html#foreign-elements)

Thus at the very least we can conclude the character has no effect whatsoever, and it also does not close the tag or anything along those lines. So in the wise words of the great Quentin:

The slash is just syntactic sugar for people who are addicted to XML.

(Source: https://stackoverflow.com/a/3558200/1266242)