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Re: user!important

From: Ian Hickson <py8ieh@bath.ac.uk>
Date: Sat, 22 Jan 2000 22:44:10 +0000 (GMT)
To: Thomas Ashe <Thomas.Ashe@blackbaud.com>
cc: "'www-style'" <www-style@w3.org>
Message-ID: <Pine.GSO.4.04.10001222238140.28560-100000@amos.bath.ac.uk>
On Sat, 22 Jan 2000, Thomas Ashe wrote:
> 
> For those of use developing web applications, I must ask how a user
> can use the display property safely.
> 
> For example, say I serve a page that displays or hides elements
> using 'display', turning them on or off as the user makes choices on
> the page.

Alarm bells immediately start ringing. Stylesheets should *never* be
used in cases where they are mandatory -- users can turn them off, can
turn off scripting, can override stylesheets, can use text browsers,
and perform any number of other atrocities to your pages.

Remember: a stylesheet is only a set of *hints*. Nothing more.


> If the user adds:
> * {display:inline ! important; visibility:visible !important}

...then he will see all the fields, as he probably intended.


> Any scripts that perform validation are suddenly no longer able to
> rely on the fact that elements are only displayed when appropriate.

Client-side scripts should not be used for validation. You have
absolutely no guarantee that client-side scripts will run, or how they
will run. Validation could be done client-side as a help to the user
to make sure that his data makes sense, but in the end the server must
ALWAYS validate the data itself.

If a page relies on stylesheets and/or scripting to be usable, then it
is clearly not using techniques for graceful degradation. Have you
checked the relevant pages on Lynx?

-- 
Ian Hickson                            ("`-''-/").___..--''"`-._   
http://www.bath.ac.uk/%7Epy8ieh/        `6_ 6  )   `-.  (     ).`-.__.`)
                                        (_Y_.)'  ._   )  `._ `. ``-..-' fL
Member, Mozilla Quality Assurance     _..`--'_..-_/  /--'_.' ,'
Browser Standards Compliance Team    (il).-''  (li).'  ((!.-'    
Received on Saturday, 22 January 2000 17:44:22 GMT

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