W3C home > Mailing lists > Public > www-validator@w3.org > July 2003

Re: http-equiv="refresh" redirects ignored in markup validator

From: Terje Bless <link@pobox.com>
Date: Mon, 28 Jul 2003 18:04:50 +0200
To: W3C Validator <www-validator@w3.org>
cc: lholst@robotics.lu.se
Message-ID: <b02000103-1026-37E28496C11511D7B4C80030657B83E8@[]>

Hash: SHA1

Lars Holst <lholst@robotics.lu.se> wrote:

>Btw, I have no idea what "HTTP redirection" is. An explanation or a link
>would be helpful.

Ah, I suspect everyone just asumed you allready knew what it was (as opposed
to how to actually implement it) since a "HTTP Redirect" is the actual
function that your "refresh" is trying to accomplish.

What you have today is a web page that contains a special instruction. The
User Agent (be it a browser or the Validator) is expected to download the
page, look at its contents, find the "refresh" instruction, wait the specified
amount of time (which just happens to be "0" seconds, but really could be
anything), and then proceede to the new address.

A "HTTP Redirect" on the other hand acts much more directly. When the User
Agent (i.e. a browser or the validator) first contacts your server and
requests the page in question, the _server_ itself will immediately tell it
that it should instead look at the new address.

The "301" and "302" which have been mentioned here are status codes (as, e.g.,
"200 OK" and "404 Not Found") that lets the User Agent know _why_ it should
look elsewhere. It might be a temporary condition, the page might have moved
permanently, the original "page" may have been a CGI or PHP script that
generated an output file and the proper HTTP status code can tell the User
Agent this and that the resulting file can be found at a new address.

There are many good reasons why it is a good idea to do this using a HTTP
Redirect, but I'm afraid that discussion would be somewhat out of scope for
this forum. There are however several excellent forums where it could be
brought up (check the comp.infosystems.www.authoring.* hierarchy on USENET for
one example).

Kynn is very much right that you need to read up a little on the technologies
involved. A casual web author does not usaully need to know such things, as
you say, but I'm afraid the effect you are after falls somewhat outside the
"casual" bracket and moves into sufficiently advanced territory that some
reading is required.

If the page Olivier pointed you at is not sufficient then that is a
shortcoming that we acknowledge, and we should seek to remedy that by
improving the resource (if you have suggestions then please do let us know!).

How much can be done to improve it -- and the other Tips in that cataegory --
depends entirely on our available resources, and these Tips have historically
suffered from lack of time and volunteers to improve or maintain them. Now
that one specific deficiency with this Tip has been pointed out I hope we will
be able to at least adress the concern raised eventually, but it may take some

( BTW, if /anyone/ have suggestions regarding this -- or any other aspect of
the Validator for that matter! -- then we very much want to hear about it.
Links we should add or new text to include would be very much welcome! )

Thanks for your feedback on this Lars!

- -- 
Of course we are the good guys! We define what is good and evil. All other
definitions are wrong, and possibly the product of a deranged imagination.
                                                         -- Stephen Harris

Version: PGP SDK 3.0.2

Received on Monday, 28 July 2003 12:05:07 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 1 March 2016 14:17:38 UTC