Boolean attributes in XHTML/HTML5

Boolean attributes in XHTML/HTML5

I always thought that in XHTML we must use e.g. disabled="disabled".
In HTML the name part of the attribute is enough. But I discovered
recently, http://dev.w3.org/html5/spec/Overview.html#boolean-attributes,
that in HTML5 disabled="" also works, and it is my guess that it's
also ok in good old XHTML and in XHTML5 (HTML5 parsed with XML parser)
for that matter.

In my opinion disabled="" is extremely confusing and should never be
used. It is my feeling that disabled="disabled" contributed to a bad
name of XHTML. The repetition was too silly. I'm wondering why
disabled="yes" or disabled="true", a little bit more sensible, was not
chosen for XML parsing?

Is there an explanation why we ended up with the awkward disabled="disabled"?


Cheers
Jesper Tverskov

http://www.xmlplease.com