JavaScript SEO is a discipline within search engine optimization that focuses on ensuring that websites and web applications that use JavaScript are properly indexed and ranked by search engines like Google. As more and more websites become dependent on JavaScript-based frameworks like React, Angular, and Vue.js, it has become crucial to understand how search engines handle JavaScript content and how to optimize this content for your SEO strategy.
What is the challenge with JavaScript and SEO?
JavaScript SEO arises as a necessity because search engines have traditionally had trouble understanding and indexing JavaScript content (and still do). When a web page uses JavaScript to load or modify content, it can be a challenge for a crawler to “see” that content if it is not handled properly. Google has gotten better at rendering JavaScript, but it requires additional resources and time compared to HTML, meaning that pages that rely primarily on JavaScript may take longer to index or not be indexed at all.
How does Googlebot work with JavaScript?
Googlebot, Google’s web crawler, indexes content in two steps:
- First pass (HTML crawl): In the first phase, Google crawls the static HTML content. If a website loads most of its content via JavaScript, Googlebot may only see a blank page or very little content in this first phase.
- Rendering (JavaScript crawl): In the second phase, Googlebot attempts to render the JavaScript content, which means it executes scripts and tries to understand the complete content of the page. This process can take time, which can lead to delays in indexing.
The problem occurs if there are errors in JavaScript or if Googlebot is unable to render the content correctly for some reason. In these cases, the page will not be indexed properly, which can hurt visibility in search results.
Important Considerations for JavaScript SEO
To ensure that your JavaScript-based website or application is properly indexed, there are several important factors to consider:
Server-Side Rendering (SSR)
One of the most effective ways to solve JavaScript SEO problems is to implement Server-Side Rendering (SSR). With SSR, the server generates the necessary HTML before the page is sent to the client. This means that when Googlebot crawls the page, it will see the full content without having to wait for the JavaScript to execute. Frameworks like Next.js (for React) and Nuxt.js (for Vue.js) support SSR and can be a valuable solution.
Dynamic Rendering
Another solution is Dynamic Rendering, where the server alternates between displaying static HTML to crawlers/search engines and JavaScript content to users. Google recommends this solution for websites with highly dynamic JavaScript, as it allows you to serve a crawler-friendly version of the page without affecting the user experience offered by the full JavaScript application.
Pre-rendering
Pre-rendering is a technique where a static version of each page is generated and served to bots, while users get the full JavaScript version. Tools like Prerender.io can help generate static copies of your JavaScript-based pages, making them easier for Googlebot to index.
Lazy Loading and SEO
Lazy loading is often used to improve the user experience by only loading images or content when needed (e.g. when the user is scrolling). However, be aware that if important content is lazy loaded via JavaScript, it can prevent Googlebot from seeing this content if it is not implemented correctly. Make sure that important SEO-relevant text and links are not hidden by lazy loading.
Best Practices for JavaScript SEO
Check indexing with Google Search Console
Use Google Search Console to check how Googlebot sees and renders your pages. The “Inspect URL” feature shows how Googlebot crawls and renders a page, and can reveal if there are any indexing issues caused by JavaScript.
Avoid relying on JavaScript alone for important SEO information
Even though Google has gotten better at understanding JavaScript, it’s still a good idea to make sure that important SEO information like meta tags, structured data, and internal links are available in the static HTML. This can help ensure that your page is indexed correctly even if problems arise.
Test your page with Google Lighthouse
Google Lighthouse is a free tool that can help you analyze your site’s performance, including SEO, and provide insight into how JavaScript affects indexing. It can also help identify technical issues like slow rendering times or poor mobile experiences that can affect both users and bots.
Progressive Enhancement
Be sure to implement progressive enhancement, where basic content and functionality is available even if JavaScript is not working properly. This can ensure a basic version of your page for both users and search engines, while advanced features are added later via JavaScript.
JavaScript SEO is an important topic for modern websites, especially those built on advanced JavaScript frameworks. To ensure that your pages are properly indexed and ranked, it is crucial to understand how search engines handle JavaScript and how you can optimize your pages with techniques such as server-side rendering, dynamic rendering, or pre-rendering.
At Click in, we specialize in technical SEO, including JavaScript SEO, and our consultants can help you optimize your website so that it is search engine friendly and ensures maximum visibility in Google.
