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RE: Issue related to WCAG checkpoint 6.1


From: Terence de Giere
Date: Feb 28, 2003 11:56AM

Paul Bohman's response to this issue is a good compact summary.

I would like to point out in addition that Netscape 3 is a good for
display problems related to lack of CSS because unlike some of the newer
browsers that do support CSS and allow the user to turn off CSS, that
CSS is often not fully disabled (inline CSS often remains intact), and
Netscape 3 simply does not support CSS but does support HTML format, so
it gives a clean view of any HTML display problems. Internet Explorer 3,
not much used now, is also a good check for early CSS support. IE3 does
not support CSS background color and problems with white text on a white
background can arise. The new Opera browser for small devices also can
sometimes have problems with text being unreadable on a background when
it reformats web pages for display. This situation is similar to a user
style sheet - does the user style sheet replace all the original style
or simply override specific selections of the original style?

Also, earlier graphical browsers such as Netscape 1, 2 and 3 had a
default gray background, while most of the recent graphical browsers
default to white, or have a setting for system colors that default to
white. This can cause problems as well because the default background
color is an unknown variable. Some designers and developers will set the
background color in the browser settings to gray or some instantly
annoying color so if the page color is not coded in either CSS or HTML,
it will be noticed, so it is a good practice to check these settings so
one can quickly notice an error. A number of HTML editors also display a
default white background when no background color is specified. This is
an important variable because foreground-background contrast is
compromised if an unexpected combination results.

I have also encountered problems when CSS and HTML format overlap. It
does not seem a problem now but it might be with some older browsers. I
had problems with deformed text when fonts were specified in
simultaneously HTML and CSS, and on some machines, problems with the
page background turning pink when white was specified both in HTML and
CSS. I was not able to determine if the problem was with the browser
(Netscape 4, IE 3 and 4) or a system or hardware problem - it did not
occur on all machines and seemed to be related to machines with more
than 256 color displays. Also both HTML and CSS color can shift
unexpectedly in some situtations. With Netscape 4 for example, some
grays may display as beige on 256 color machines.

In summary we need to check for CSS presentation problems in the
following categories

1. Browser is not graphical and does not support CSS (e.g., Lynx)
2. Browser is graphical and does not support CSS (e.g., Netscape 1, 2, 3)
3. Browser is graphical and has partial or erroneous CSS support
(e.g., IE 3, Netscape 4)
4. Browser is graphical and has good CSS support but when CSS is
turned off, inline CSS or other properties of embedded or linked
CSS are not disabled. (e.g., Earlier versions of Opera, and most
of the recent browsers)
5. Browser overrides CSS and HTML format with special style sheets
(e.g. Opera 7)
6. Browser allows a user style sheet (recent IE and Opera)
7. Overlap of HTML and CSS may cause problems in some instances
8. CSS and HTML display anomalies may be a function of video
hardware, OS, and browser

Terence de Giere

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