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Re: Testing via disabling CSS file

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From: Steve Green
Date: Jul 6, 2023 12:50AM

WCAG 2.1 does not require websites to work without CSS. However, if you use the W3C Website Accessibility Conformance Evaluation Methodology (WCAG-EM) 1.0 or the Report Tool, one of the requirements is to specify the relied-on technologies. If you want to claim that CSS is not a relied-on technology, you will need to test with it turned off.
https://www.w3.org/TR/WCAG-EM/
https://www.w3.org/WAI/eval/report-tool/evaluation/define-scope

If you do this, you potentially need to test all the success criteria with CSS turned off. If the website wasn't specifically designed with work without CSS all sorts of things could go wrong. Anything hidden using "display:none" or the "clip" technique or positioned off-screen will become visible, which may or may not be a problem. CSS content will not be displayed.

Links will be underlined, and both links and buttons will receive focus and have focus indicators, so you don't need to worry about that. "Proper" buttons will have a border, but <div role="button" tabindex="0"> buttons won't - you will just see the text. They will receive focus and have focus indicators. But there's lots more that can go wrong.

There are still a small number of people who use text browsers that don't support CSS. Only a month or so ago a Lynx text browser user complained on the WAI forum about her inability to use a Google survey. She said that other user agents do not meet her needs. See https://lists.w3.org/Archives/Public/w3c-wai-ig/2023AprJun/0016.html

There are a number of reasons you might want to test with CSS turned off, such as:

1. Legislation or a commercial contract might require it. For instance, the GDS Service Standard says that all UK central government websites must work without CSS, JavaScript or images.

2. You want to support the widest possible variety of user agents and user preferences.

3. You are a masochist and like to build websites using progressive enhancement because it's good engineering practice, not because you actually need to.

4. You want to see if there's any hidden content you don't know about. I find there are often components such as dialogs, widgets or error messages that are only displayed under certain circumstances, and you may not know about them if you don't have a full functional specification.

5. You are testing for conformance with WCAG 1.0 for some reason.

Steve Green
Managing Director
Test Partners Ltd