In a recent article on SearchEngineLand, Barry Schwartz writes that Google could stop crawling AJAX sites in the very near future. At the time of writing, he alluded to the fact that the change could come as soon as this week.
However, we do know that Google has improved the way in which they crawl websites over the years and since 2013 they have claimed to be rendering full pages and seeing them the way users do. Therefore, these guidelines become unnecessary as Google no longer needs webmasters to alter their code to be able to crawl it completely. We do, however, always advise that plain text and therefore easily crawlable content should make up a large proportion of your webpage, giving engines the best chance to index your website and therefore content.
Illyes also added that in his opinion, websites built solely on AJAX don’t provide the best user experience to their users. It could even be that Google shares this opinion, which would help explain the rumoured change.
On the whole, webmasters of AJAX sites shouldn’t panic just yet. Hopefully this is just an indication that Google is crawling fully rendered pages and not AJAX code. However, as a safety precaution and for best practice, do make sure your site is utilising sufficient plain text to give your site the best advantage of getting your content indexed.