Skip to content

Technique H74:Ensuring that opening and closing tags are used according to specification



This technique relates to 4.1.1: Parsing (Obsolete and removed) (Sufficient, together with H93: Ensuring that id attributes are unique on a Web page and H94: Ensuring that elements do not contain duplicate attributes when used with Ensuring that Web pages can be parsed by using one of the following techniques:).


The objective of this technique is to avoid key errors that are known to cause problems for assistive technologies when they are trying to parse content which involve having opening and closing tags that are not used according to specification. There are several validators that a developer can use: validation reports generally mention these types of errors. This technique deals only with errors related to incorrectly formed opening and closing tags. The document type declaration is not strictly necessary for this type of evaluation, but specifying the document type declaration makes it easier to use a validator.


Example 1: HTML

HTML pages include a document type declaration (sometimes referred to as !DOCTYPE declaration). A developer can use offline or online validators (see the Resources section) to check that all id attribute values are unique and that opening and closing tags are used according to the specification.

Other sources

No endorsement implied.



  1. Check that there are closing tags for all elements with required closing tags.
  2. Check that there are no closing tags for all elements where closing tags are forbidden.
  3. Check that opening and closing tags for all elements are correctly nested.

Expected Results

Steps 1, 2, and 3 are true.

Back to Top