Accessibility checklist

by on 7 November 2019 in nablopomo, accessibility

A list of accessibility recommendations, tips and resources. Last updated on 26 May 2020.

Accessibility is not just a checkbox exercise

Although I find checklists useful, it’s worth remembering that accessibility shouldn’t be reduced to a checkbox exercise. Craig Abbott explains it nicely in this post.

Accessibility is not just a checkbox exercise. It’s about inclusion. It’s providing the same level of service and human rights to everybody and culturally we need to embrace it in everything that we do.
— Craig Abbott

Typography

  • Nest headings in order (for example, h1, h2, h3)
  • Don’t skip heading levels
  • Use semantic mark-up (for example, headings, lists and blockquotes)
  • Links should look like links (for example, blue and underlined)
  • Lines should be less than 80 characters wide
  • Add suitable vertical spacing between lines and paragraphs
  • Avoid italics, block capitals or justified text
  • Use a san-serif font with thick letters
  • Make sure text can be resized

Read my post about how improving typography can help us to meet user needs.

Written content

  • Use plain English
  • Explain unusual words and jargon
  • Explain abbreviations in the first instance
  • Don’t rely on link title attribute
  • Put the most important information at the start
  • Explain what a user has to do in a clear and concise way
  • Use headings and lists to break the content into chunks
  • Download links labels should include file format and size
  • Headings, links and button text must be unique and descriptive
  • Each page should have a unique, descriptive h1 and page title

Tables

  • Make sure tables are accessible
  • Only use tables to present data
  • Use tables as accessible alternatives to charts and infographics
  • Split complex tables into multiple small ones
  • Use correct table markup for headers, rows and cells, so screen reader users can understand and navigate them

Read my post about making data tables more accessible.

Charts

Read my post about accessible charts.

Colour and contrast

  • Check colour contrast between text and background
  • Check design works in black and white
  • Don’t communicate using colour alone
  • Check design works in high contrast mode

Interaction

Forms

Images

  • Images should have good alternative text
  • If images are purely decorative, then they need an empty alt tag alt=""
  • Avoid using images of text

Read my post about SVGs icons.

Layout and structure

  • Use HTML sectioning elements like <header>, <main> and <nav>
  • Add a skip to main content link
  • Layout should be consistent and predictable
  • Do not rely upon shape, size, or visual location (for example, “Click the square icon to continue” or “Instructions are in the right-hand column”)
  • Check reading and navigation order is logical
  • Check page is readable and functional when text size is doubled
  • Don’t use duplicate id attributes

iframes

  • Use the iframe title attribute to give the content a descriptive title
  • Make sure interactive elements inside an iframe are usable with a keyboard
  • Make sure interactive elements have a clear focus style
  • Test the iframe is readable and functional with browser zoom at 200%
  • Test the content doesn’t overflow or become truncated when font size is increased

Manual tests

Read Quick Tips for Windows High Contrast Mode from Sarah Higley.

Automatic tests

Remember that automatic tests aren’t perfect.

It’s important to note, however, that automated accessibility testing tools can only catch 30-50% of your accessibility defects. — Deque

Read building the most inaccessible site possible with a perfect Lighthouse score from Manuel Matuzović.

Other accessibility checklists