Browsers recover silently
Browsers tolerate some markup that a stricter parser rejects. This is useful for ordinary web rendering, but it does not establish the well-formed XML needed for applicable iXBRL.
Use the correct parser
Check plain HTML against its applicable construction rules. For iXBRL, add strict XML and relationship checks; do not impose an identical XHTML test on every plain HTML job.
Validate meaning as well as syntax
A correctly formed fact can use the wrong period, dimension, unit or scale. Compare extracted values to approved disclosure under the qualified reviewer’s checklist.
Keep evidence
Record validator version, plugins, disclosure system and taxonomy configuration. Review warnings and official TEST messages through the authorized workflow; a clean screenshot is not an assurance opinion.
Scope and primary reference
Educational production guidance only. Client disclosure approval, legal/accounting judgement, qualified tagging review and filing authority remain separate. Confirm the appropriate qualified review and current requirements for each live assignment.
Reference: Current official SEC guidance. Verify the current requirements for the agreed job.