Published on February 8, 2024

What CMOs Need to Know about JavaScript SEO for Ecommerce

Considering the high-level marketing tasks that CMOs focus on, JavaScript SEO is an afterthought. We don’t blame you, it’s rather technical. However, when you’re dealing with a JS-heavy website, it is important to know how it can impact your ecommerce performance. 

In this article, we’ll discuss how JavaScript SEO affects ecommerce websites, common enterprise SEO challenges, and how CMOs can optimize JavaScript SEO for ecommerce websites to enhance sales.

The Relationship between JavaScript and Ecommerce Websites

In the past, JavaScript was avoided when building an ecommerce website due to search engine optimization (SEO) and performance concerns. But, as the technology evolved, JavaScript has become integral to delivering highly interactive user experiences that drive conversions.

In short, JS enables complex, interactive interfaces with elements like image carousels, sticky headers, filtering mechanisms, and more. It also enables faster page transitions, animations, and other dynamic effects. But although this all contributes to a slick user experience (leading to higher conversion rates), it can fall short if you don’t address the technical SEO elements. 

4 Common JavaScript SEO Issues in Ecommerce Websites

JavaScript-based ecommerce websites deal with slow PageSpeed and indexing. This is problematic for sites with extensive product pages that are diverse and regularly updated.

These challenges are just the tip of the iceberg. Let’s delve into more details.

1. Slow PageSpeed

JavaScript files can be render-blocking, meaning they delay the rendering of a page until they are fully executed. Consequently, they can negatively affect the Core Web Vitals scores—a vital ranking factor of Google, particularly in these areas:

In short, JavaScript tends to decrease your page load time, leading to lower Core Web Vital scores and higher bounce rates.

2. Slow Crawling and Indexing Results

Due to the dynamic nature of JavaScript content, indexing JS websites must go through a two-step process. As a result, this can slow the indexing time and cause some key SEO content to be missing. For instance, the meta title and description might not be visible to crawlers, and links may not be followed, leading to imperfect crawling and indexing.

Related: Learn how search engines crawl and index JavaScript content in detail.

Without being indexed, your onsite SEO elements can’t be used to determine rankings and boost visibility. And when you compete with other ecommerce sites to promote time-sensitive products or campaigns, the slow indexing process prevents you from gaining momentum.

3. Limited Crawl Budgets

Imagine a search engine crawler as a busy shopper on a tight budget, zipping through your website like a bustling marketplace. They have limited time and resources and must prioritize the most valuable items (pages) to index and understand. Now, throw in the complexities of JavaScript indexing, and things get tricky for ecommerce websites. Every element on a page, including JavaScript files, takes a bite out of the crawler’s budget. And when your budget is zero, search engines can’t crawl or index your pages, putting them on hold until the next crawl budget comes. 

Therefore, it isn’t recommended to have large, unoptimized JavaScript files. They can quickly deplete your valuable crawl budget, leaving valuable pages partially crawled or completely unexplored. 

Top tip: learn more about the role of crawl budget on indexation and JavaScript SEO in this white paper.

4. Mobile Friendliness

Ecommerce sites rely heavily on mobile traffic, and JavaScript is frequently used to create responsive and mobile-friendly designs. However, some JavaScript implementations can cause performance issues on mobile versions of ecommerce websites. 

A prime example of these is pop-ups. While these are great for ads and conversion on ecommerce sites, Google penalizes websites that use unoptimized pop-ups on mobile devices. This includes pop-ups that are difficult to close, auto-playing videos, or covering the main content.

To ensure the mobile version of your ecommerce website doesn’t hurt your organic performance, follow these 7 best practices to create mobile-friendly JavaScript websites.

How to Optimize JavaScript SEO for Ecommerce Websites

There are several options to solve JavaScript SEO for ecommerce. While some solutions demand high upfront costs and resources, one enterprise SEO tool requires near-zero development time and costs.

Many websites try to solve their JavaScript SEO problems by implementing server-side rendering (SSR), where your server renders the pages and returns a fully rendered version to crawlers. Since you’re building your own servers, this method is generally expensive and complicated to set up. Another solution is to minify and compress their JavaScript code, but that ultimately leads to performance issues, too. 

To optimize ecommerce JavaScript SEO while keeping costs low and not sacrificing performance, the best option is to implement prerendering using an enterprise SEO tool like Prerender

Prerender renders and caches your pages ahead of time. This tool fetches all web page elements, executes any JavaScript code, and saves a pre-built HTML snapshot. It will then feed the 100% rendered pages to search engine crawlers, accelerating the indexing time and ensuring perfect indexation.

Since Prerender does the prerendering, search engine crawlers need less crawl budget to index your ecommerce pages. This allows you to have a bigger crawl budget to be allocated to index pages that affect your bottom line quickly and perfectly.

Websites that use Prerender have an average page load of 0.05 seconds, while those that don’t take 5.2 seconds—that’s a 104x page speed increase!

Another benefit of using a tool like Prerender is that it can distinguish between human users and search engine crawlers. So, while crawlers get the prerendered pages, your customers will be served the interactivity your JS-based website offers. 

Overall, it cuts down the time search engines take to index and rank your product pages while allowing you to serve customers with an immersive JavaScript shopping experience. It’s a win-win solution for site visibility and user satisfaction!


The interactive elements JavaScript brings can greatly enrich your ecommerce website, helping you create an engaging user experience that helps boost sales. However, CMOs must remember that the heavier your ecommerce website is, the likelier it will face JavaScript SEO problems.

While optimizing JavaScript SEO comes with its roadblocks, Prerender will help your ecommerce site get past those challenges with ease. Thanks to the simple installation process and navigation system, even a non-technical generalist can run it and use the insights to improve sales performance.

Get started with Prerender today and see its impact on your ecommerce business!


If your website has over 10,000 URLs, you could qualify for a FREE live Javascript SEO Audit. 

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