[Prev][Next][Index][Thread]

MAIL DELIVERY FAILURE



"A.P.Miller@ncl.ac.uk" is not registered for electronic mail.

This reply has been generated automatically.  In case of difficulty,
please contact the Postmaster at the University of Newcastle who can
be reached at:

    postmaster@ncl.ac.uk

Your message follows:-
----------------------

From www-disw-request@w3.org Wed Aug  4 20:58:57 1999
Received: from www19.w3.org by cheviot.ncl.ac.uk id <UAA07328@cheviot.ncl.ac.uk>
  (8.7.6/ for ncl.ac.uk) with ESMTP; Wed, 4 Aug 1999 20:58:56 +0100 (BST)
Received: (from daemon@localhost)
	by www19.w3.org (8.9.0/8.9.0) id PAA12586;
	Wed, 4 Aug 1999 15:53:57 -0400 (EDT)
Resent-Date: Wed, 4 Aug 1999 15:53:57 -0400 (EDT)
Resent-Message-Id: <199908041953.PAA12586@www19.w3.org>
Message-ID: <37A89A45.E65050A6@w3.org>
Date: Wed, 04 Aug 1999 14:53:41 -0500
From: Dan Connolly <connolly@w3.org>
X-Mailer: Mozilla 4.51 [en] (WinNT; U)
X-Accept-Language: en
MIME-Version: 1.0
To: Eliot Christian <echristi@usgs.gov>
CC: www-disw@w3.org
References: <4.2.0.58.19990804083323.00a04b60@opsmail.er.usgs.gov>
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by www19.w3.org id PAA12570
Subject: Re: Safe use of Meta Tags
X-List-URL: http://www.w3.org/pub/WWW/Archives/Public/www-disw/
Resent-From: www-disw@w3.org
X-Mailing-List: <www-disw@w3.org> archive/latest/83
X-Loop: www-disw@w3.org
Sender: www-disw-request@w3.org
Resent-Sender: www-disw-request@w3.org
Precedence: list

Eliot Christian wrote:
> 
> It is common to find several ways of representing very similar
> concepts in HTML Meta Tags. Yet, metadata authors may wish to
> assert that various tags ought to be considered equivalent for
> search purposes.
> 
> Toward this goal, some of us are trying out a mechanism where
> an additional attribute is provided within the Meta element.
> The attribute is a "Z" number (corresponding to registered
> concepts in the Z39.50 Bib-1 Attribute Set, Use Attributes).
> We are putting the Z attribute as the last part of a Meta
> element, in the hope that it will be safely ignored by
> processors that don't understand what it is. For example,
> 
> <head>
> <title>My Very Own Web Page</title>
> <meta NAME="GILS.Originator" CONTENT="U.S. Geological Survey" z="1005">
> <link REL="schema.GILS"      HREF="elements.html#table_1">
> <meta NAME="AUTHOR"          CONTENT="Eliot Christian" z="1005">
> <meta NAME="dc.creator"      CONTENT="Eliot Christian" z="1002">
> <link REL="schema.dc"        HREF="http://purl.oclc.org/metadata/dc/">
> </head>
> 
> Is this safe?

sort of. It doesn't conform to any W3C specs, but most software
will "safe"ly ignore it. But you're not guaranteed that somebody
else isn't using the same syntax with different semantics.

If you want that guarantee, use XML namespaces; i.e.

<head xmlns:z="http://lcweb.loc.gov/z3950/-or-some-such">
<title>My Very Own Web Page</title>
<meta NAME="GILS.Originator" CONTENT="U.S. Geological Survey"
	z:Bib-1="1005" />
<link REL="schema.GILS"      HREF="elements.html#table_1" />
<meta NAME="AUTHOR"          CONTENT="Eliot Christian"
	z:Bib-1="1005" />
<meta NAME="dc.creator"      CONTENT="Eliot Christian"
	z:Bib-1="1002" />
<link REL="schema.dc"        HREF="http://purl.oclc.org/metadata/dc/" />
</head>

and describe what this syntax means at
	http://lcweb.loc.gov/z3950/-or-some-such

Note the /> at the end of the meta tags, to conform with XML.

For details, see:

XHTML™ 1.0: The Extensible HyperText Markup Language
     A Reformulation of HTML 4.0 in XML 1.0
W3C Working Draft 5th May 1999
           http://www.w3.org/TR/1999/xhtml1-19990505 

especially section 3.1.2 "Using XHTML with other namespaces"

-- 
Dan Connolly, W3C
http://www.w3.org/People/Connolly/