Valid HTML

For: Design, Development

Parsing (4.1.1 level A)

https://www.w3.org/WAI/WCAG21/Understanding/parsing

Validate all page HTML and avoid significant validation / parsing errors. Automated testing alongside some manual testing can be used for this.

Check for the following:

  • Use unique ids on a given page, for example make sure the same id does not appear more than once on a page.
  • Nest elements according to their specification. For example, test there is no div tag inside a span or li tag inside a div without having ul or ol tags.
  • Avoid duplicate attributes, for example providing alt text twice for the img tag
  • Make sure that HTML has both start and end tags.
  • Make sure no outdated (obsolete) HTML tags are used.