Google’s Martin Splitt Says JavaScript Can Slow Your SEO

Thanks to its high-level of adaptability, JavaScript (JS) has been in use in some shape or form for more than 20 years and remains one of the most popular programming languages used to build websites.

However, Google’s Martin Splitt, a webmaster trends analyst, recently suggested that webmasters should begin moving away from the coding language to rank most quickly on search engines.

In an SEO Mythbusting video exploring the topic of web performance and search engine optimization, Splitt and Ada Rose Cannon of Samsung found themselves talking about JavaScript.

Specifically, they discussed how using too much JS can drag down a site’s performance and potentially drag them down in Google’s search index.

How JavaScript Holds Content Back

One of the biggest issues that arise with overusing JS is when sites publish content on a daily basis.

Google uses a two-pass indexing process to help verify content before it is added to the search index. In the case of a JavaScript-heavy page, Google first renders the non-JS elements like HTML and CSS. Then, the page gets put into a queue for more advanced crawling to render the rest of the content as processing resources are available.

This means Java-heavy pages may not be completely crawled and indexed for up to a week after being published.

For time-sensitive information, this can be the difference between being on the cutting-edge and getting left behind.

What You Can Do Instead

Splitt offers a few different techniques developers can use to ensure their site is being efficiently crawled and indexed as new content is published.

One way to get around the issue would be to use dynamic rendering, which provides Google with a static rendered version of your page – saving them the time and effort of rendering and crawling the page themselves.

The best course of action, though, would be to simply rely primarily on HTML and CSS for time-sensitive content.

Splitt takes time to explain that JavaScript is not inherently bad for your SEO or search rankings. Once they are indexed, JS-heavy sites “rank just fine.” The issue is ensuring content is crawled and indexed as quickly and efficiently as possible, so you can always be on the cutting edge.

The discussion gets pretty technical, but you can view the entire discussion in the full video below: