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RE: Client Side vs. Server Side Image Maps

From: Nick Kew <nick@webthing.com>
Date: Fri, 1 Feb 2002 07:55:07 +0000 (GMT)
To: Jon Hanna <jon@spinsol.com>
cc: <w3c-wai-ig@w3.org>
Message-ID: <20020201074811.O4206-100000@fenris.webthing.com>

On Fri, 1 Feb 2002, Jon Hanna wrote:

> > Does anyone know why, it is recommended that you use client-side
> > images maps instead of server-side.
>
> Because the client side maps can give the client information about
> how the purpose of each area (through highlighting the shapes for
> graphical users, the alt text on <area>s for text users, the title
> attribute etc.) This cannot be done with serverside maps obviously,
> as no more information is available than the is given by the image
> itself.

That's not strictly true.  You can define a serverside map which
is equivalent to a clientside one, in the sense that the UA can
retrieve it and display the options.  Lynx does that.  Of course,
it still costs an HTTP transaction.

What the WCAG and other guidelines are rather weaker on is where
an imagemap doesn't have regions, but is for example a lat/long
input to a geographic map - which of course can't be done
clientside without introducing other - more serious - accessibility
issues.  My own approach and recommendation is to offer alternative
<input>s of type text in this situation.


-- 
Nick Kew

Site Valet - the mark of Quality on the Web.
<URL:http://valet.webthing.com/>
Received on Friday, 1 February 2002 02:55:12 GMT

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