I'm looking for some kind of authoritative stance on this - imagine the following scenario:
A site is striving to meet Level A of the WCAG 2.0 specification.
In the header of the site which runs throughout, there is a text size widget that allows the user to select normal, large and extra-large text. When the user does so, all the text throughout the site is consistent and legible regardless of content.
Now it is remarked that the site is not accessible because when the text is scaled using the in-built controls of a browser, there are display/legibility issues. In the case of this example, this is in Firefox when:
- Text only zoom option is selected
- The size is increased over 120%
Now this problematic for me, on the following reasons:
This is a browser implementation and not a website implementation. How can I possibly consider the impact of any arbitrary user client? Someone could write a browser with an option to make all the text the same color as a background element.
We have provided, agnostic of browser, a means to scale text to a reasonable degree that works fine across our target browser space.
With the following in mind, how can I convince a client looking to apply WCAG 2.0 that it's unreasonable and that our in-built text-size selector is a necessary technique for meeting the spec?