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RE: MWABP: 3.6.4 Support a non-JavaScript Variant if Appropriate

From: Rotan Hanrahan <rotan.hanrahan@mobileaware.com>
Date: Wed, 25 Nov 2009 12:08:47 -0000
Message-ID: <D5306DC72D165F488F56A9E43F2045D30219D50B@FTO.mobileaware.com>
To: <achuter@technosite.es>, "MWI BPWG Public" <public-bpwg@w3.org>
Cc: "David Torres" <dtorres@technosite.es>
While a DDR (if well maintained) can indicate whether or not the client is script-capable, it is also possible that the end user has disabled scripts, so <noscript> can be useful here. Of course, if DCCI/OMADPE were available then you could test dynamically for script-enablement, but these technologies are yet to make any appearance in the market whereas DDRs actually exist today. (They have existed for years, as the venerable WURFL proves, and professional/commercial DDRs are available from many vendors too.)

If your DDR doesn't indicate script-capability, and the script isn't that important, then don't use the script. You'll save a bit of bandwidth too. If the script is important, and there's some doubt about whether the device will execute it, the <noscript> element is advised.

If you don't have a good DDR at your disposal, and you need to detect if script is present, you can try a scripted sniffer at the start of the session. The script merely causes something to be retrieved from the server (or passed in a subsequent request) that tells the server that scripts are being executed. Of course, these sniffers can become complex over time, and there's always the danger that a sniffer may adversely affect the "snifee".

If you are targeting just a few (high-end) devices, scripts can be wonderful enhancements. If you are trying to cover a wide range of devices (1000s of models) then scripts can be quite challenging. So another motivation for providing a non-script version is because you've spent all your time/energy/money dealing with just a few fancy devices :)

CIA/CTO MobileAware.

-----Original Message-----
From: public-bpwg-request@w3.org [mailto:public-bpwg-request@w3.org] On Behalf Of Alan Chuter
Sent: 25 November 2009 11:39
To: MWI BPWG Public
Cc: David Torres
Subject: MWABP: 3.6.4 Support a non-JavaScript Variant if Appropriate

Following from the discussion in the call yesterday regarding this BP 
[1], I would remind people that as well as the script element, XHTML 
(and Basic) [4] provides the noscript element. Any content within this 
element will be ignored if script is executed but rendered if it is not. 
Unless I'm missing something, this would be a much more elegant way of 
fulfilling the intent of this BP.

Surprisingly this solution is not mentioned in the BP1 document [2] 
either, which simply suggests a test for compliance, although it does 
link to WCAG 1.0 checkpoint 6.3 [3] which says "If it is not possible to 
make the page usable without scripts, provide a text equivalent with the 
NOSCRIPT element, or use a server-side script instead...".

This seems (unless I'm  missing something) like a much more reliable 
technique than checking against a DDR.



[1] http://www.w3.org/TR/mwabp/#bp-devcap-scripting-support

[2] http://www.w3.org/TR/mobile-bp/#OBJECTS_OR_SCRIPT

[3] http://www.w3.org/TR/WAI-WEBCONTENT/wai-pageauth.html#tech-scripts


Alan Chuter
Departamento de Usabilidad y Accesibilidad
Technosite - Grupo Fundosa
FundaciĆ³n ONCE
Tfno.: 91 121 03 30
Fax: 91 375 70 51

Received on Wednesday, 25 November 2009 12:09:31 UTC

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