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Tree model integrity (fwd)

From: John Nissen <jn@tommy.demon.co.uk>
Date: Wed, 25 Aug 1999 22:18:50 GMT
Message-Id: <52611@tommy.demon.co.uk>
To: jbrewer@w3.org
Cc: w3c-wai-ig@w3.org
Hello Judy,

I've been asked to give a talk on the "state of the art" on
web accessibility to the ICTA on 4th September. 
Thus I've been thinking about the guidelines, and also the 
reaction of the chi-web group to ideas on accessibility.  
I think most sites could be simplified a lot, and 
that will be the greatest boost to accessibility, hence 
the provocative claims and suggestions in forwarded message below.  
I'd be interested in your reaction.  I'm copying to the wai-ig as well.
(For their information, the abovementioned chi-web group is 
concerned with computer-human-interface aspects of the web.)


Forwarded message follows:

>Date: Wed, 25 Aug 1999 21:02:57 GMT
>From: jn@tommy.demon.co.uk (John Nissen)
>Reply-To: jn@tommy.demon.co.uk
>Message-Id: <52603@tommy.demon.co.uk>
>To: chi-web@acm.org
>Cc: jn@tommy.demon.co.uk
>Subject: Tree model integrity

>A few weeks ago we had a thread about the importance of building
>up a coherent mental model, so you know where you are when you
>are navigating a site (but, if you get lost, you can quickly find
>yourself again).
>Now, during your navigation of the web, the browser builds up a 
>tree of visitations.  You are aware of this when you use the back 
>and forward buttons, and also when the colour of links change.
>I believe many problems that users have with web applications are
>due to the applications messing up the browser's tree.  Sites should
>have all information in a hierarchy, so that the model of the site
>maps onto the browser model.  And sites should avoid "short cut" buttons, 
>instead leaving the user to use the browser to do the navigation.
>I claim:
>A.  It is possible to present almost all information in a tree hierarchy,  
>where the nodes are pages and the branches are hypertext links.
>(Help information, glossary of terms and dictionaries are exceptions, 
>since cross-linking is inevitable.)  
>B.  Most navigation buttons introduced to make it faster or simpler
>for the user actually have the opposite effect, because they
>subvert the browser's own controls.
>Some implications:
>1.  Searching
>The search engine should present results on a single page.
>It should not break the results into a number of pages and have
>"next" and "previous" buttons.  Instead the user should be allowed
>to scroll.  The browser back button will then take the user straight
>back to where they started with the search form, no messing.
>Search refinement should be from this same point.
>2.  Back buttons
>The application should never supply its own back, forward
>or home buttons.
>3.  Internal links
>There should be no links between different points of the same
>page.  All links should point down the hierarchy.  (Exceptions
>are for cross-referencing in help files and dictionaries.)
>Applications should never have "top of the page" buttons.
>4.  Site entry
>Users should be encouraged to visit the site starting at the
>top.    Then the tree of the site will map directly onto the
>browser tree as it creates it.
>5.  Table of contents or index
>This should be on a separate page at a level above the contents
>6.  References
>These should generally be in a page by themselves at the lowest
>Cheers from Chiswick,

Access the word, access the world       Tel/fax +44 181 742 3170/8715
John Nissen                             Email to jn@tommy.demon.co.uk
Cloudworld Ltd., Chiswick, London, UK   http://www.tommy.demon.co.uk
Received on Wednesday, 25 August 1999 17:42:01 UTC

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