Ten common Accessibility errors

Web developers attempting to build accessible websites often make the same mistakes time and time again. Although they're trying their hardest, sometimes their overzealousness gets in the way and actually hinders the accessibility of their websites.

The 10 guidelines below tell you what not to do, so you too don't fall foul of these same common accessibility errors...


1. Don't use verbose ALT text
Accessible web developers often insert far too much ALT text on to images, in the hope that this will help screen reader users. ALT text for information-based images should be short and succinct, and contain no more information than is in the image. Decorative images should always be given null ALT text, or alt="", so that they're ignored by screen readers.

2. Don't use random characters to separate links
One of the minor accessibility guidelines states that adjacent links should be separated with non-link text, because some very old web browsers had problems with adjacent links. This guideline is no longer relevant and any invisible characters (usually vertical bars) are announced to screen reader users as ‘vertical bar’, which is of course nonsensical and makes it harder for these users to work through the page.

3. Don't insert text into empty form fields for the sake of it
Another old and outdated guideline states that any empty form field should have placeholding text inside of it. This guideline originally existed as very old screen readers weren't always able to pick up empty form fields. All major screen readers now pick up empty form fields so it's safe to ignore this guideline.

4. Don't use access keys
You can assign access keys to any link to provide keyboard shortcuts to them. In reality, access keys can override keyboard shortcuts for screen readers, rendering key screen reader functionality useless. The other problem with access keys is there's no convention, so the few sites that use them do so in whichever way they choose.

5. Don't use the table summary (unless it actually adds value)
Screen readers read table summaries aloud, providing a summary of the table content prior to listening to the whole table. The table summary should always be omitted from a layout table. Websites using a tabular layout sometimes have table summaries of ‘layout table’ which of course add no value at all.

6. Don't forget about the content
The way that content is structured on any website is an enormous part of accessibility. A website may be perfectly coded and conform to the highest coding standards, but if its content is poorly structured, the site will prove difficult to impossible for some special needs web users. Consider front-loading content so that each paragraph begins with the conclusion, and ensure content has been broken down into manageable chunks with descriptive sub-headings. Use lists wherever appropriate, and stick to plain and simple language.

7. Don't worry too much about accessibility statements
Many websites attempting to offer great accessibility create lengthy accessibility statements, typically containing information on the accessibility features of the website. Disabled or not, as web users we don't tend to consult 'help' guides on any site - rather, we stumble along attempting to complete our goals. Although there's nothing wrong with making an accessibility statement page there's no need to spend too much time on it.

8. Don't agonise over acronyms and abbreviations
Declaring whether something is an acronym or abbreviation is easy to do in the HTML, simply by using the or tags. The full acronym or abbreviation can then be expanded upon within this tag. Most screen readers don't support these tags though so they don't really offer much of a benefit to disabled users.

9. Don't change the tab order (unless you have a very good reason to do so)
The tabindex attribute can be used to change the on-page tabbing order but is rarely necessary. Screen reader and keyboard-only users tab through links and form items in the order in which they're placed in the HTML source code. Provided that users tab within each section roughly from top-left to bottom-right (which they will) then the tab order is perfectly adequate.

10. Don't forget to listen with a screen reader
Whilst you're building your accessible website don't forget to keep testing the pages as you build them. In particular, you'll want to listen to them with a screen reader to check that accessibility features work as planned.

Associated Link: Webcredible - user experience consultancy

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