Last Updated: February 18, 2019
· paulmatthews

Why Javascript Should Be Covered From An SEO Point Of View Within The Front End World

In 2019, with the prominence of CMS throughout the world wide web, it's important to understand how impactful are the plugins which are powering the engine behind an enquiry-based site, an eCommerce one or a simple blog. Javascript is, of course, the core part of such plugins and, therefore, to understand its purpose within a Search Engine is to win the eternal SEO race. Let's analyse how to optimise your JS resources for search purposes.

The Crawling Process

When it comes to SEO, it's important to understand that every search engine crawls a website first, in order to understand the content which is successively indexed on SERP (https://www.wordstream.com/serp). Of course, such crawlers (or user agents) aren't extremely up to date with the latest development technologies and, therefore, they forget about core parts of your site when it comes to reading what's on your page. Javascript is, unfortunately, one of the resources which are skipped within the crawling process.

What Happens To My JS Then?

Chrome 41, which is the latest version of Googlebot (Google's user agent, to be clear) doesn't crawl any JS library but, instead, it renders the resources to then index the whole package of data. To clarify, the process for what concerns a page which doesn't have any form of JS installed is Crawl and then Index, whilst for a page that has any form of JS installed (jQuery, Node, React) the user agent will first crawl the page, to then render the non-HTML and CSS resources and, finally, index the whole package.

What's The Best Approach For JS SEO?

In order to optimise JS for SEO purposes, it's important to understand the fact that the architectural planning for what concerns your page is a top priority: if you have any content within a block of Javascript code, it won't be crawled straight from Googlebot (or any other user agent) but it will follow the rendering process mentioned above, slowing down your entire ranking process. This is something which is usually underestimated by many SEO specialists around the world, but it's the main reason why many Javascript-heavy sites have a terribly slow ranking process.

The Mobile Matter

When it comes to mobile SEO, there's a strict need for speed optimisation, which is, once again, heavily related to JS resources. In fact, if we analyse a web page's composition, we can easily see how 56% or more of the loading speed (especially on mobile) is related to Javascript pieces. Many mobile app development companies in the UK, especially Apadmi ( https://www.apadmi.com/ ) are, in fact, actively looking to reduce their JS usage when it comes to mobile versions of their popular plugins. This is heavily related to the fact that, moving on, there will definitely be a need to implement much more rendering heavy technologies, given the fact that Machine Learning (and, therefore, Python-related applications) are going to be extremely popular in the near future.