Create Web documents that are well-formed
no. 050
Make sure HTML tags are nested according to the specification
Browsers and other user agents, including assistive technologies, can accurately interpret and parse HTML content as long as they are well-formed, meaning that the elements are nested according to the rules set in the HTML specification. The goal is to avoid parsing errors that will potentially cause assistive technologies and other user agents to inaccurately interpret the markup and lead to misleading or false information due to markup not being structured as expected.
To do this, simply make sure that user agents, including assistive technologies, can accurately interpret and parse content. If the content cannot be parsed into a data structure, then different user agents may present it differently or be completely unable to parse it. Specify the version of HTML used and rely on a validation service to make sure the markup does not contain well-formedness errors. When HTML documents are free of such errors, the interpretation by assistive technologies such as screen readers will be much smoother and the information conveyed to users, that much more accurate.
User Story
As a user using assistive technology, I want my tools to reliably interpret the HTML [...]