html - XHTML5 and HTML4 character entities

Question

Welcome To Ask or Share your Answers For Others

html - XHTML5 and HTML4 character entities

asked Oct 24, 2021 in Technique[技术] by 深蓝 (71.8m points)

Does XHTML5 support character entities such as   and —. At work we can require specific software to access the admin side of the site, and people are demanding multi-file-upload. For me this is an easy justification to require migrating to FF 3.6+, so I'll be doing it soonish. We currently use XHTML 1.1, and upon moving to HTML5, I'm only having issues with character entity names... Does anyone have a doc on this?

I see there is a list on the WHATWG spec but I'm not sure if it affects files served as application/xhtml+xml. By any means the two mentioned trigger errors in both Chromium nightly and FF 3.6.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙；凝视深渊过久,深渊将回以凝视…

297 views

1 Answer

深蓝 · Answer 1 · 2021-10-23T17:51:22+0000

There is no DTD for XHTML5, so an XML parser will see no entity definitions (other than the predefined ones). If you wanted to use an entity you would have to define it for yourself in the internal subset.

<!DOCTYPE html [
    <!ENTITY mdash "—">
]>
<html xmlns="http://www.w3.org/1999/xhtml">
    ... &mdash; ...
</html>

(Of course using the internal subset is likely to trip browsers up if you serve it to them as text/html. Sending an internal subset in a non-XHTML HTML5 document is disallowed.)

The HTML5 wiki currently recommends:

Do not use entity references in XHTML (except for the 5 predefined entities: &, <, >, " and ')

And I agree with this advice not just for XHTML5 but for XML and HTML in general. There's little reason to be using the HTML entities for anything today. Unicode characters typed directly are far more readable for everyone, and &#...; character references are available for those sad cases when you can't guarantee a 8-bit/encoding-clean transport. (Since HTML entities are not defined for the majority of Unicode characters, you are going to need those anyway.)

Categories

html - XHTML5 and HTML4 character entities

Please log in or register to add a comment.

Please log in or register to answer this question.

1 Answer

Please log in or register to add a comment.

Just Browsing Browsing

Most popular tags