Why is Java Script SEO important? — Björn Darko // Searchmetrics

Quotes

• “Javascript is a developers language which is created out of HTML. It is a code language that developers use to code functions and websites.” -Björn

• “Javascript is one of the hot topics in the SEO industry and for Google, its different than just crawling pure HTML, it is more complex. There are a lot of important functions that are based on javascript such as a video player, notifications, or some shiny thing that pops-up on a website. Now there are complete websites based on javascript, most of them are Angular JS React.” -Björn

• “The way that I think about the use of javascript is its all about the bells and whistles, you want on your website. The motions, the triggers, the dynamic contents, pop-ups and flashes, and the widgets.” -Ben

• “Google has its process and it includes these three steps which include crawling, indexing, and the carry engine which spits out the result. A crawler crawls the web, discovers URLs, passes HTML source code, extracts all the links and CSS, and sends those to the indexer. The indexer then tries to make sense of the link and analyzes the content and the relevancy and use this so-called web rendering services where they actually render the full page in order to check how it actually looks like.” -Björn

• “This is how Google actually works when it comes to javascript crawling, we can actually say its the same process but heres the problem. It sends everything to the indexer and the indexer needs to render the page in order to get the links with javascript. Its different from HTML where they get the links beforehand.” -Björn

• “Additionally, you have to make sure that the crawling and indexing is very good because if its not, it is too complicated for Google to do the whole process.” -Björn

• “Googles Martin Splitt, who teaches a lot of javascript SEO announced in the last Google Developer Conference that Google is using second wave indexing for javascript content. Because it is so complex, they needed to be a bit smarter, and the way they do it is through second wave indexing.” -Björn

• “Second wave indexing means that Google is crawling all those javascript content and file and just throws it into the index without rendering it in the first instance, they render it in the second and between the first and second time, they might be weeks in between. This is the dangerous thing here because if you rely on search engine rankings then it takes a lot of time for Google to actually render your page and fully understand your website content and purpose.” -Björn

• “If you are based on a full and complete javascript-based web application, you need to have server-side rendering in place. This means that you actually provide a fully-rendered HTML version of your website to Google.” -Björn

• “One way you can do it is throughstatic renderingwhere you have a pre-rendered version of URL and store it in the cache so that the server is sending this already pre-rendered files whenever Google comes. The other is a dynamic rendering. There is a navigation point already on the site and the output will be HTML that is already doing the drop for Google on the server and sending another pre-rendered version here to Google.” -Björn

• “It seems like there will be some risks here for Google. Lets use security through the airport example. If I say, I have unloaded my suitcase and I am just going to show you a picture of everything thats inside. Okay great, heres a picture of everything in my suitcase you should let me go through security and down the road you actuallyget a chance to check my suitcase. Well, you dont know what is actually in the suitcase when it gets past. So how is this not creating a security risk for Google?” -Ben

• “What they do is like static rendering, meaning that they take a snapshot of the website, saw it in a cache, and whenever Google comes, they get the version of the cache. The thing here is, they dont renew the version whenever there is a new article. So what Google gets, is a version of a website that is maybe a month old.” -Björn

• “The other thing we saw is paginated pages. If you have pagination on the website, the content on page one should be different than pages 2, 3, 4, 5, or 6. But because this pre-caching of the websites content costs so many resources, this publisher just had one hash version of page one and then lowered it up to page ten so that you have exactly the same content on ten pages which is, of course, causing duplicate content forms and its not good.” -Björn

• “Google says they fully understand javascript and they cant do it although they recommend that you use methods like server-side rendering because they know it is very complicated for them.” -Björn

• “Normally if you have your javascript website, its just javascript code, right? What you definitely should do is put all the code and meta-information and everything which is important for Google.” -Björn

• “And if you want to audit your site, you can actually use a crawler with a javascript crawl function, and Searchmetrics is doing this as well. But you can also use whats called a view source plug-in. What it does is compare the raw source code with a rendered source code and you can already see if there are any differences.” -Björn