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Re: HELP: XHTML 1.1 and usemap's value

From: Jukka K. Korpela <jkorpela@cs.tut.fi>
Date: Tue, 29 Jan 2002 00:51:17 +0200
To: www-html-editor@w3.org
Message-Id: <20020128225116.MQVI24910.fep01-app.kolumbus.fi@oemcomputer>
[posted to comp.infosystems.www.authoring.html
and mailed to www-html-editor@w3.org]

In message news:a33jn8$12s$1@mordred.cc.jyu.fi
Ville Seppänen <rissepp@itu.st.jyu.fi> wrote:

> The problem is that a document which contains a client-side imagemap
> does not validate as XHTML 1.1. I have used <img usemap="#mymap" ...
> /> and later <map id="mymap">. 
> While validating it as XHTML 1.1 an error is
> Error: character "#" is not allowed in the value of attribute
> "usemap" 
> However, the same document validates as XHTML 1.0 Transitional and
> Strict. Any ideas what is wrong? I havent found any hints that would
> suggest this is changed in 1.1 and usemap's correct value still seems
> to be idref (URI). 

This is confusing, and what might be done to reduce the confusion is a 
correction to the XHTML 1.1 specification, which is why I'm sending a 
copy of this to maintainer of that document.

In XML (as well as in SGML), when an attribute is declared to take IDREF 
value, the value must be an identifier as such, without any # prefix, and 
an identifier that is defined elsewhere in the document in an ID 
attribute. More formally:

"Validity constraint: IDREF

Values of type IDREF must match the Name production, and values of type 
IDREFS must match Names; each Name must match the value of an ID 
attribute on some element in the XML document; i.e. IDREF values must 
match the value of some ID attribute."


In XHTML 1.0, the usemap attribute in <img> is declared as %URI whereas 
in XHTML 1.1 it is declared as IDREF. The same applies to some other 
attributes as well, like usemap in <img>. I haven't studied the 
differences systematically, but surely there are changes that should be 
listed at
It is not sufficient to mention that "On the a and map elements, the name 
attribute has been removed in favor of the id attribute". Related actual 
changes elsewhere should be explicitly mentioned too. A clarifying 
reference could be made to

This is a real change that makes some valid XHTML 1.0 documents invalid 
under XHTML 1.1. In the other direction, things are different, since 
usemap="foo" is valid in XHTML 1.0 but lacks useful meaning, since the 
semantics is as defined in HTML 4.01:
"usemap = uri [CT] 
This attribute associates an image map with an element. The image map is 
defined by a MAP element. The value of usemap must match the value of the 
name attribute of the associated MAP element."

The semantic change should be noted too. XHTML specifications generally 
make normative references to HTML specifications as regards to semantics, 
and here the reference needs to be modified suitably.

Yucca, http://www.cs.tut.fi/~jkorpela/
Pages about Web authoring: http://www.cs.tut.fi/~jkorpela/www.html
Received on Monday, 28 January 2002 17:51:19 UTC

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