Mobile-First Indexing

When Google announced the shift to Mobile-First Indexing, they focused on communicating the need to make mobile versions of a page match the desktop versions of a page – especially in relation to on-page content, schema, links, canonical tags, as well as title and description tags. They also included alt tags and HERFlang tags in the list of things that should match, between mobile and desktop. One of the difficulties that some sites experienced in making this shift, is that many mobile sites used JavaScript to display or expose content in the more condensed mobile UX scenarios. According to Google, this is less of a concern in Mobile-First Indexing, because of the improved ability to render and index information in JavaScript – using a two phased approach to crawling, indexing, rendering and ranking – using the first phase to collect and index information from HTML, and the second phase to collect and index information from JavaScript.