At what point is the canonical tag crawled

[ao.com]

Do search engines (specifically Google) crawl the url in the canonical tag as it loads or do they load the whole page before crawling it?

Thanks,

[AlanMosley]

Do you mean follow the canonical?

Eitehr way logic would suggestthat the page is read first. As html tags have a begining and end tag, trying to crawl a half loaded page would not work untill the end tags are read.

I am curiouse as to why you would want to know this?

[ao.com]

It's for a temporary fix for a page that has been poorly made in a CMS. The template for the page contains a malformed canonical element so we're trying to bandage it up by inserting some js that removes this element into the body of the page. Obviously if the canonical URL is crawled before the js can run then it's pointless even trying.

[AlanMosley]

Yes i think you are better off putting your time into fixing the canonical tag on the server side. It may even look sus doing what you are doing.

I would go to WMT and view as google bot and see how they see it, i think they will read the tag before any js.