Help:HTML in wikitext: Difference between revisions

[[Wikipedia:HTML Tidy]] is an outdated HTML4 library that is [[:mw:Parsing/Replacing Tidy|slated for removal]]. Tidy parses the MediaWiki output and cleans it up to increase the likelihood that valid HTML4 is rendered. For example, with Tidy enabled, {{tag|br|o}}, {{tag|br|c}}, {{tag|br/|o}}, {{tag|br.|o}} all rendered as {{tag|br|s}}. Tidy is not enabled for [[Wikipedia:Help:MediaWiki namespace|MediaWiki interface pages]]. Tidy was never perfect and has been known to introduce errors.

In some pages in the [[Wikipedia:Help:MediaWiki namespace|MediaWiki namespace]], typically the short messages like button labels, HTML is not parsed, and tags will be exposed.

User and sitewide [[Wikipedia:CSS]] and [[Wikipedia:JavaScript]] pages are interpreted as if inside a {{tag|pre|o}} block. See [[Wikipedia:Help:User style|Help:User style]].

{{Main|Wikipedia:Help:Markup validation}}

The MediaWiki software attempts to fix HTML errors, but it does not catch all of them. Where HTML is used, it is helpful to verify it with the [[Wikipedia:W3C Markup Validation Service|W3C Markup Validation Service]].