I recently published the results of my JavaScript SEO experiment where I checked which JavaScript frameworks are properly crawled and indexed by Google. The results were shocking; it turns out Google has a number of problems when crawling and indexing JavaScript-rich websites.
Google managed to index only a few out of multiple JavaScript frameworks tested. And as I proved, indexing content doesn’t always mean crawling JavaScript-generated links.
This got me thinking. If Google is having problems with JavaScript crawling and indexation, how are Google’s smaller competitors dealing with this problem? Is JavaScript going to lead you to full de-indexation in most search engines?
If you decide to deploy a client-rendered website (meaning a browser or Googlebot needs to process the JavaScript before seeing the HTML), you’re not only risking problems with your Google rankings — you may completely kill your chances at ranking in all the other search engines out there.
Google + JavaScript SEO experiment
To see how search engines other than Google deal with JavaScript crawling and indexing, we used our experiment website, http:/jsseo.expert, to check how Googlebot crawls and indexes JavaScript (and JavaScript frameworks’) generated content.
The experiment was quite simple: http://jsseo.expert has subpages with content parsed by different JavaScript frameworks. If you disable JavaScript, the content isn’t visible — i.e. if you go to http://jsseo.expert/angular2/, all the content within the red box is generated by Angular 2. If the content isn’t indexed in Yahoo, for example, we know that Yahoo’s indexer didn’t process the JavaScript.
Here are the results:
As you can see, Google and Ask are the only search engines to properly index JavaScript-generated content. Bing, Yahoo, AOL, DuckDuckGo, and Yandex are completely JavaScript-blind and won’t see your content if it isn’t HTML.
The next step: Can other search engines index JavaScript?
Most SEOs only cover JavaScript crawling and indexing issues when talking about Google. As you can see, the problem is much more complex. When you launch a client-rendered JavaScript-rich website (JavaScript is processed by the browser/crawler to “build” HTML), you can be 100% sure that it’s only going to be indexed and ranked in Google and Ask. Unfortunately, Google and Ask cover only ~64% of the whole search engine market, according to statista.com.
This means that your new, shiny, JavaScript-rich website can cost you ~36% of your website’s visibility on all search engines.
Let’s start with Yahoo, Bing, and AOL, which are responsible for 35% of search queries in the US.
Yahoo, Bing, and AOL
Even though…
