rel attribute.
Values:
alternate: Links to an alternate version of the document (i.e. print page, translated or mirror) author: Links to the author of the document bookmark: Permanent URL used for bookmarking help: Links to a help document license: Links to copyright information for the document next: The next document in a selection nofollow: Links to an unendorsed document, like a paid link. ("nofollow" is used by Google, to specify that the Google search spider should not follow that link) noreferrer: Specifies that the browser should not send a HTTP referer header if the user follows the hyperlink prefetch: Specifies that the target document should be cached prev: The previous document in a selection search: Links to a search tool for the document tag: A tag (keyword) for the current document
<a rel="value">