Tips to Improve Your JavaScript: A Guide for Web Developers

Paul Fraser
Published 04/04/2022
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magnifying glass over javascript codeJavaScript is everywhere. For scrolling down menus, hiding information with a click of a button, or displaying animation. As a developer, JavaScript gives you the decision power to dictate the website user experience.

While JavaScript is widely used and extremely popular, the same cannot be said for JavaScript SEO. There’s been a lot of debate on if JavaScript is the right programming tool if you want to level up your search engine efforts. The point is, that JavaScript is not necessarily bad for SEO. But it is definitely nuanced and tricky.

JavaScript, unlike other programming languages, is heavy on page load and performance. And while you use JavaScript to improve the user experience, it may end up doing the opposite and hamper your website’s performance in search engines due to the complexity of rendering JavaScript websites.

Google has made it clear that it processes JavaScript in three phases:

  • Crawling
  • Rendering
  • Indexing

The process of Google rendering content from JavaScript takes days or even weeks. This isn’t a downloaded HTML response

javascript for web developers

 where Google can render the content without any additional interaction. The scale of individually rendering JavaScript content is not practical for Google considering the trillions of web pages it discovers every day.

The responsibility ultimately falls on the developers to implement JavaScript best practices to ensure a website performs well and is not penalized for poor core web vitals. Most of the processes will more or less be similar. You just have to go the extra mile so that Google can recognize and seamlessly process JavaScript.

Let’s take a look at some of the top measures you can take to improve your JavaScript and its performance in search engines.



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1. Prevent Accidental Indexing of Your JavaScript by Google

Indexing is one of the ways that Google processes your JavaScript. While indexing the JavaScript can take time, don’t block crucial resources that prevent Google from indexing your content.

A very common mistake that websites make is that they end up including the “do not index” tags in HTML because the content isn’t rendered in the first instance or the page times out. Googlebot simply finds the tag and moves on instead of returning to run the JavaScript that is inside the source code.


2. Enable Crawling

While crawling JavaScript sites was challenging for Googlebot in the past, it isn’t anymore. Google can effectively crawl your website by fetching a URL for a page from the crawling queue. It checks if it allows crawling but due to the reasons mentioned above, websites often accidentally block access to resources.

How do you expect Google to rank you when it can’t even render your website?

You need to allow crawlers to access your website content with one HTTP request for the HTML and the text you want to be indexed. In the case of JavaScript, the easiest way to allow crawling is, in your robots.txt add:

User-Agent: Googlebot
Allow: .js
Allow: .css


3. Provide Sitemap

If Google hasn’t indexed your page, it’s likely that it didn’t discover it. While creating a sitemap isn’t a mandate, it considerably helps Google understand the relationships between your web pages and index them properly.

If you’re acquainted with JavaScript, you’d know that it has routers to clean URLs and a module that can create sitemaps. You can get them by searching for your system + router sitemap, such as “Vue router sitemap.”


4. 4-Step JavaScript SEO Implementation Process

You need to undertake some hygiene measures to ensure that Google doesn’t miss out on indexing your pages due to JavaScript issues.

Identify the Amount of JavaScript your Website Needs: Knowing that JavaScript may pose SEO problems in the future, you can check how much the website actually relies on JavaScript for its content. You can do so by disabling JS on the chrome extension.

If your website is heavily reliant on JS, you’ll need to test the rendered HTML using debugging tools. You can utilize Google Search Console. It offers a URL inspection tool that provides detailed crawl, index, and serving information about your pages, directly from the Google index.

Verifying Whether Googlebot Caches Your Crucial Content and Tags: Google relies heavily on caches to save on their computer power. Its pages, API requests, files, everything is cached before sending it to the renderer.

Cached Google versions improve your page load speed and help with SEO. But in cases where Google shows a 404 page or unavailable cached websites, it means the page isn’t cached. To cache your webpages, you can request indexing from Google or submit the updated XML sitemap.


Using Chrome Extensions

Extensions make your life easier; whether you’re an SEO executive or a web developer. They help you streamline tasks for web developers and SEO professionals.

There are many debugging tools available in the Chrome web browser that help you test and debug your JavaScript SEO issues. Some of these tools are ‘Web Developer’ and ‘View Rendered Source.’


Check Tags

When you have a large website with many URLs, it is common to suffer from speed issues with non-trivial rendering times. There are also a lot of issues with duplicate content issues in JavaScript. In such cases, even optimizing your tags can help.

Choose the type of content you want to index and set canonical tags. Also, ensure that you follow the normal SEO rules of optimizing your meta tags and title tags.


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5. Follow Web Standards for Linking

Web standards are the basic rules you have to follow while linking. If your links aren’t per the web standards, Google misses them. It makes it hard for Google to read internal pages as there is no clear relationship between the search engines and the pages. Following the web standard simply means linking to internal pages using the HREF attribute:

<a href="your-link-goes-here">Your relevant anchor text</a>


6. Work Your JavaScript for Lazy Loading Images

Lazy load is a great way to decrease your page load time. But improper lazy loading can again prompt Google to skip your website. Just like we talked about following the web standards for linking, you need to follow the web standard for images as well. Ensure that your images are linked from the ‘src’ HTML tag:

<img src="image-link-here.png" />

While using JavaScript-based lazy loading libraries, you can also replace the ‘src’ tag with a gif that can load more quickly.


7 Ensure JavaScript Is Visible in the DOM Tree

There’s a high possibility that JavaScript won’t change visually and you wouldn’t know if it changes your metadata or content under the hood. To ensure that your content is visible, all you need to do is check your DOM tree. If it is loaded there, Googlebot will see it even if it is hidden. But if it’s not visible after a click, the content won’t be found.


8 Fix JavaScript Rendering Issues

Since you now know that the major issue with JavaScript SEO is the complexity of rendering, you need to undertake some measures that make it easy for Google to better crawl sites with JavaScript and fix Javascript rendering issues.

Server-side rendering (SSR): Most JavaScript frameworks such as Angular, Vue, and React default to client-side rendering. This is where they keep the browsers at the forefront rather than the search engine.

You can rather opt for pre-rendering your website or SSR.

This can ensure your site is Googlebot-friendly. You can deliver the pre-rendered HTML version of your site to Google while your users get the browser version. There are different ways you can execute SSR.

  • Hybrid rendering: Hybrid rendering is a combination of both client-side rendering and server-side rendering. The core content of the page is displayed on the server. It is further sent to either the browser or search engine requesting the page.
  • Dynamic rendering: Dynamic rendering is the process of serving content based on the user agent requesting it. This is the best way to strike a balance between allowing Google to read and understand your JavaScript website whilst also providing an enhanced user experience. Here, Server-side rendering creates a rendered HTML version of each URL on-demand.
  • Incremental Static Regeneration: This is the process of creating a pre-rendered HTML version of a URL in advance and storing it in the cache.


Bottom Line

Overall, acing your JavaScript SEO will involve a lot of technical SEO skills which calls for equal involvement of an SEO professional as well as a developer. It is highly recommended that both read Google’s official documentation and troubleshooting guide for more JavaScript SEO basics. JavaScript is going to stay. Create a collaborative culture where you can combine and share SEO and JS knowledge if you want to taste success in JavaScript SEO.