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Re: data protocol URIs (was CSS selectors and xml:id)

From: David Woolley <david@djwhome.demon.co.uk>
Date: Mon, 9 May 2005 20:26:30 +0100 (BST)
Message-Id: <200505091926.j49JQUq01644@djwhome.demon.co.uk>
To: www-style@w3.org

> If there had been a fragment part, I believe that it would have been

Fragments are not part of URIs but only part of URI references.  data
URIs are URIs, not URI references.

>From RFC 2396:

4. URI References

   The term "URI-reference" is used here to denote the common usage of a
   resource identifier.  A URI reference may be absolute or relative,
   and may have additional information attached in the form of a
   fragment identifier.  However, "the URI" that results from such a
   reference includes only the absolute URI after the fragment
   identifier (if any) is removed and after any relative URI is resolved
   to its absolute form.  Although it is possible to limit the

Furthermore, and I believe this means that fragments may be used with
data URIs:

4.1. Fragment Identifier

   When a URI reference is used to perform a retrieval action on the
   identified resource, the optional fragment identifier, separated from
   the URI by a crosshatch ("#") character, consists of additional
   reference information to be interpreted by the user agent after the
   retrieval action has been successfully completed.  As such, it is not
   part of a URI, but is often used in conjunction with a URI.

and

   The semantics of a fragment identifier is a property of the data
   resulting from a retrieval action, regardless of the type of URI used
   in the reference.  Therefore, the format and interpretation of
   fragment identifiers is dependent on the media type [[27]RFC2046] of the
   retrieval result.  The character restrictions described in Section 2

Which means that a fragment on a data URI has the same meaning as the
same fragment on an HTTP URI that fetches the same data.

This is why # is not allowable, unencoded, within data URIs.
Received on Monday, 9 May 2005 19:26:37 GMT

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