Re: Back reference

Abigail (abigail@fnx.com)
Mon, 21 Jul 1997 11:25:18 -0400 (EDT)


From: abigail@fnx.com (Abigail)
Message-Id: <199707211525.LAA25397@fnx.com>
Subject: Re: Back reference
To: rory@omega.ru.ac.za
Date: Mon, 21 Jul 1997 11:25:18 -0400 (EDT)
Cc: panos.matsinopoulos@mailcity.com, www-html@w3.org
In-Reply-To: <m0wqGhn-001ZFUC@cs.ru.ac.za> from "Rory Freeman" at Jul 21, 97 01:32:42 pm

You, Rory Freeman, wrote:
++ 
++ Hi
++ 
++ > I am getting more specific. I write an html file. I want to create a
++ > link to the file that called this html file I write. The URL that calls
++ > my html file is not always the same. Is there any way to reference the
++ > caller of my html file. Is there any variable that the browser can
++ > understand.
++ 
++ Using SSI you can do:
++ 
++ --
++ 	You came from <!--#echo var="HTTP_REFERER"--> .


Please, please stop spreading disinformation.

First of all, browsers are required to send the referer URL, and in
certain cases not even supposed to. What is your SSI going to do when
there is no HTTP_REFERER?

Furthermore, this will at best create a *forward* link to the previous
page, which is not at all the same as a back reference.  Try following
such back references *twice*. You'll go back to the page you just left,
instead of going back 2 pages in your history stack.

Lastly, this will either screw caching, or get screwed by caching.
What if person A visits the pages, loads the proxy with that page and
then person B visits the page, getting the page served from the proxy's
cache? He will then go back to A's previous page, not his previous page;
and your page will look foolish. And in case the proxy will always do a
'get if modified' request, you've disabled all the benefits of caching -
as the page will always be fresh.

Please read <URL: http://www.ny.fnx.com/abigail/HTML/Misc/back_button.html>


Abigail