In 2009 Google released a proposal for making AJAX based content crawlable.
The original proposal can be viewed here:
https://googlewebmastercentral.blogspot.co.il/2009/10/proposal-for-making-ajax-crawlable.html
The release of this proposal was motivated by the fact that approximately 70% of websites at the time used JavaScript, whereas search engines were incapable of properly scanning JavaScript URLs.
The proposal set a scheme that allowed search engines to accept static pages with matching content to pages that are loaded with AJAX without violating Google’s guidelines.
In this update, Google have announced they are now capable of indexing AJAX based content without aid, deprecating their earlier proposal and encouraging webmasters to allow Googlebot access to the page’s CSS and JS.
There are several big news and call-to-actions in this announcement for SEOs and web builders:
- AJAX based Websites that weren’t previously crawlable are currently being scanned and indexed, we as SEOs need to make sure that proper portions of our content are exposed.
- Website builders must update their working methods, builders using the AJAX crawling scheme can now decide if they wish to continue using the old method (which is currently still supported by Google) or inform their clients and start following the new guidelines.
Google strongly encourages site builders to follow the new guidelines, so it’s safe to assume they’ll eventually stop supporting the AJAX crawling scheme.
Google’s official announcement can be viewed here:
http://googlewebmastercentral.blogspot.com/2015/10/deprecating-our-ajax-crawling-scheme.html