Im working on a site that has had an SEO expert review it. They have advised me that we should apply canonical tags on every other page
<!-- http://www.example.com/detail/table&r=dining-room -->
<link rel="canonical" href="http://www.example.com/detail/table"/>
is it really required that the canonical tag only appears on every other page, or will it play nicely if it appears on the same page?
The reason I ask this is: isn't the link also telling Google that it is infact on the right page?
RFC 6596: The Canonical Link Relation specifies:
The target (canonical) IRI MAY:
o […]
o Be self-referential (context IRI identical to target IRI).
So, yes, you can use rel-canonical even on the canonical page.
It seems to be an argument between Google and Bing. Google doesn't mind if you have the canonical tag pointing to itself. Bing does mind and you lose their trust for the use of canonical tags. Look at this article: http://www.northsideseo.com/google-vs-bing-canonical-tag/
来源：https://stackoverflow.com/questions/20340008/can-the-canonical-tag-be-used-on-all-pages