AJAX
AJAX is used with JavaScript and XML to update content without the need to refresh the entire page, allowing less visual intrusion. Previously used to assist Google with the rendering of JavaScript content, our Hangout Notes below cover how Google currently deals with AJAX content, with recommendations and examples.
Google Needs to Access JS Files & Server End Points Used For AJAX Requests
If AJAX requests that are needed to download JavaScript on page load are being blocked in robots.txt, then Googlebot won’t be able to see or index any of the content that these requests will generate.
AJAX Crawling With Escaped Fragment URLs is a Deprecated Set up
Using AJAX crawling set up with escaped fragment URLs is a deprecated set up. At some point Google will be turning off support for escaped fragment URLs and will only crawl and render the hashbang URLs themselves.
AJAX Content Loaded After 20 Seconds Won’t Be Seen by Google
Content not loaded onto a page via AJAX immediately, probably won’t be seen by Google. John says 20-30 seconds is too long.
AJAX Loaded Hamburger Menus Won’t Be Seen by Google
Hamburger menus with content loaded via AJAX probably won’t be seen by Google.
Google is OK with Manipulated Back Buttons
Google doesn’t usually have a problem with Manipulating the back button behaviour, such as preventing users going back to Google’s search results.
Escaped Fragment Support will be Dropped
Google’s support for the escaped fragment solution is going to continue in the mid-term.