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?


1 Answer 1


If your site doesn't scale properly when using browser controls then that sounds like the site isn't built properly.

Build it to proper HTML / W3C standards and let the user use whatever browser they want. The in-page accessibility controls are mostly useless in websites because users who have certain requirements will have already set up their browser for that (specifying fonts, zoom sizes etc)

The user shouldn't have to select certain options on your website just so they can read it. Heck, if they have a disability / impairment that means they can't even see the option you've provided then they can't select it in the first place. But they can set up the browser to their own required settings themselves.

Making an accessible site is basically just about following correct development standards. If you do that then the site will more-or-less just be accessible as a result (although you still need to ensure the content itself is accessible when added in, obviously).

  • +1, I agree with this answer fully, although I must remark that I find the particular requirement that OP is trying to meet a rather difficult criteria not just a "correct development standard". WCAG 2.0 requires "The page is readable and functional when the text size is doubled." which breaks many designs if the page isn't a simple list or grid. But this is me just being vapid and ranting.
    – DasBeasto
    Mar 8, 2016 at 13:12
  • @DasBeasto One of the benefits of responsive design is that it can help with the text sizing issue. Built with that in mind it would mean the design itself adapts to the size of the content (in this case being the size of the font, as well as the volume of content). OP may not be building a RWD site here though, but it's an additional benefit of that design methodology.
    – JonW
    Mar 8, 2016 at 13:15
  • The site handles text size increases from the browser up to a certain amount, it's just the 'text only zoom' option in Firefox that compromises everything; we have Masonry-driven dynamic blocks on the front page that just can't fit the massive increase in text because they don't scale with this particular setting. I'm still philosophically disgruntled with pandering to browser implementation which like mentioned leaves us at the mercy of the vendor. But yes, the in-site text selector is outdated and pointless.
    – njp
    Mar 8, 2016 at 15:57
  • 1
    @njp The accessibility guideline states that text should be able to be zoomed up to 200%, so if it's breaking at only 120% then there is certainly something wrong in the code. The site doesn't have to look perfect when zoomed, but it does have to be fully usable and readable. You're not designing for a browser, you're designing to established standards.
    – JonW
    Mar 8, 2016 at 16:06
  • I guess my question is where does 'text only zoom' fit into the picture? Normal zoom works fine up to 200% as mentioned. The W3C spec for 1.4.4 says: "resized without assistive technology up to 200%", but we fall over when 'text only zoom' is enabled. Again, this is an extra variable introduced by Firefox and I don't quite see where the 'control' zoom behaviour lies. They could introduce an 'elongate text' option for people, and we'd have to code to that?
    – njp
    Mar 8, 2016 at 16:34

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