[m0th87]

Don't believe the hype. Google has been saying that they can execute javascript for years. Meanwhile, as far as I can see, most non-trivial applications still aren't being crawled successfully, including my company's.

We recently got rid of prerender because of the promise from the last article from google saying the same thing [1]. It didn't work.

1: http://googlewebmastercentral.blogspot.com/2014/05/understan...

[thoop]

Todd from Prerender.io here. We've seen the same thing with people switching to AngularJS assuming it will work and then coming to us after they had the same issue.

[1] This image is from 2014, when Google previously announced they were crawling JavaScript websites, showing our customer's switch to an AngularJS app in September. Google basically stopped crawling their website when Google was required to execute the JavaScript. Once that customer implemented Prerender.io in October, everything went back to normal.

Another customer recently (June 2015) did a test for their housing website. They tested the use of Prerender.io on a portion of their site against Google rendering the JS of another portion of their site. Here are the results they sent to me:

Suburb A was prerendered and Google asked for 4,827 page impressions over 9 days Suburb B was not prerendered and Google asked for 188 page impressions over 9 days

We've actually talked to Google some about this issue to see if they could improve their crawl speed for JavaScript websites since we believe it's a good thing for Google to be able to crawl JavaScript websites correctly, but it looks like any website with a large number of pages still needs to be sceptical about getting all of their pages into Google's index correctly.

1: https://s3.amazonaws.com/prerender-static/gwt_crawl_stats.pn...

[grey-area]

Perhaps this could be down to response times too, they might crawl much quicker if given static HTML very quickly?

What were the page render times for the two types of page?

[walshemj]

Interesting will have to reinvestigate this

[mixonic]

I noticed our companies Ember.js based SPA site not being indexed well until I added a sitemap. Then it quickly appeared in the rankings.

Historically Google has been using some fork of Chrome 10 when indexing. I'm unsure what impact that is having on the reliability of app rendering, but I also trust the Google search team has done reasonable checks ensuring common sites and frameworks render correctly.

I strongly suggest using a sitemap for JS rendered sites, based on my own experience.

[tracker1]

It's also worth noting that even when they do get JS delivered content, it updates much less frequently...

Then again, I really like react+redux+koa (r3k) for client-server rendering.... Hoping to do something more serious with it in the next few months at work.