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Re: XHTML 1.0 DTD's

From: Ian Jacobs <ij@w3.org>
Date: Sun, 12 Dec 1999 15:15:23 -0500
Message-ID: <3854025B.F214F54A@w3.org>
To: JAMESICUS@aol.com
CC: www-validator@w3.org
JAMESICUS@aol.com wrote:
> In the W3C XHTML 1.0 Working Draft, 24 November 1999, the following
> Transitional DocType/DTD is listed:
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
> After converting my web pages to XHTML, and incorporating the above,  I
> successfully Validated them via the W3C Validator.
> The W3C XHTML 1.0 Proposed Recommendation, 10 December 1999, lists the
> following Transitional DocType/DTD:
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
> "http://www.w3.org/TR/1999/PR-xhtml1-19991210/DTD/xhtml1-transitional.dtd">
> I used this on one of my converted web pages to see if it would validate - it
> did, in fact either of the above DTD's work.
> Question: which should I use as a preference?

Two different flavors of system identifier appear above. These
are two different flavors due to W3C policy.

The first URI refers to the "latest version" of the DTD. This
DTD will change each time W3C publishes a new draft of xhtml1.
You should avoid using that reference so that if the DTD changes
in a way that's incompatible with your document or software, you
won't be affected.

Instead, use dated URIs to point to specific versions of
DTDs. Once W3C publishes a document, we make every effort to
maintain it in its original form. So if you refer to a specific
DTD now, it should never change in the future (as long as W3C
service the URI).

I hope this helps.

 - Ian

Ian Jacobs (jacobs@w3.org)   http://www.w3.org/People/Jacobs
Tel/Fax:                     +1 212 684-1814
Cell:                        +1 917 450-8783
Received on Sunday, 12 December 1999 15:12:25 UTC

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