Your website has no major code errors

Parsing is the way software like web browsers and assistive technology read and understand a website. It’s important that the different technologies your users use to view your website don’t have trouble parsing your website. Parsing is all about your website’s code.

All your users will benefit from a website built on clean and modern HTML. Your website will work properly in all web browsers and on all kinds of devices, from computers to tablets to smartphones.

Your users who rely on assistive technology will benefit from a well-made website as the technology often relies on HTML parsing. Bad or broken HTML is more likely to cause parsing problems for assistive technology and so increase the chance of users leaving your website.

What to do

This is a wide-ranging guideline, one that changes with time as standards evolve. Your best protection is hiring a web designer who knows parsing well. Find one through recommendations and ask them about their approach to web standards and accessibility.

Here are the most common issues to watch out for:

  • Ensure HTML elements have complete start ( < > ) and end ( </ > ) tags where needed.
  • Nest all HTML elements correctly (for example, list objects within an ordered or unordered list).
  • Use unique Ids.
  • Check that HTML elements don’t contain duplicate attributes.


A good – though not foolproof – way to test your website is a HTML validator tool. A validator gives you an idea of how well technology can parse your website. Use it to create a list of priorities.

See also

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About Author

I'm Luke, I started Wuhcag in 2012 to help people like you get to grips with web accessibility. Check out my book, 'How to Meet the WCAG 2.0'.

2 comments on “4.1.1 – Parsing (Level A)

    Rob V says:

    Hi Luke, do web pages need to pass W3C HTML validation to be considered accessible and to, in part, satisfy criteria 4.1.1 ?

      Luke McGrath says:

      Hey Rob, The requirement is that HTML is valid, it doesn’t specify that this means you use the W3C Validator. In practice though, yes use this as your test in addition to a sense check – valid HTML can still be the wrong HTML!


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