This page lists allowed and proposed extension values for the http-equiv="" attribute of the <meta> element in HTML. For the detailed registration requirements, see the specification.
The following extensions conform to all the registration requirements in the HTML spec and are therefore allowed in valid documents.
|PICS-Label||Labels that help content advisory software protect children from potentially harmful material [more]||PICS Label Distribution Label Syntax and Communication Protocols|
The following proposed extensions do not yet conform to all the registration requirements in the HTML spec and are therefore not yet allowed in valid documents.
|x-dns-prefetch-control||Allows turning prefetching "on" or "off". There's an equivalent HTTP header. Which takes precedence is undefined.||Controlling DNS prefetching|
|X-UA-Compatible||Specifies the IE rendering mode that should be used to render the document. Widely used, but not registered with IETF/IANA.||MSDN: Defining Document Compatibility|