JavaScript SEO refers to the practice of optimizing websites that use JavaScript frameworks or libraries for search engine crawling and indexing. JavaScript is a popular programming language used to create dynamic and interactive web pages, and it is often used to create modern web applications.

However, search engines have traditionally had difficulty crawling and indexing JavaScript-based websites, as they rely heavily on static HTML content. JavaScript SEO involves optimizing various technical aspects of a website to ensure that search engines can effectively crawl and index its content.

Some best practices for JavaScript SEO include:

Server-Side Rendering: Rendering content on the server before it is sent to the user’s browser can make it easier for search engines to crawl and index the content.

Lazy Loading: Delaying the loading of non-critical content until the user scrolls down can improve page speed and user experience, while also making it easier for search engines to crawl and index the content.

Dynamic Rendering: Using dynamic rendering techniques to create static HTML versions of dynamic pages can make it easier for search engines to crawl and index the content.

Use of Sitemaps: Including a sitemap that lists all the URLs on your website can help search engines discover and index all your content.

Optimizing Metadata: Ensuring that your website’s metadata, such as title tags and meta descriptions, are properly set and optimized for search engines.

By implementing these best practices, website owners can improve the visibility and ranking of their JavaScript-based websites in search engine results pages, leading to increased traffic and better user engagement.

How Does Google Crawl and Index JavaScript?

Google processes JS in three phases:

1. Crawling
2. Rendering
3. Indexing

Image Source: Google

Google has significantly improved its ability to crawl and index JavaScript-based websites in recent years, but it still has some limitations. Here’s a general overview of how Google crawls and indexes JavaScript-based websites:

Googlebot crawls the page: Googlebot, Google’s web crawling bot, starts by requesting the page’s HTML from the website’s server, just like it would for a traditional website.

JavaScript files are fetched and executed: Googlebot will then fetch any linked JavaScript files and execute them, including any that may be embedded in the HTML page.

Rendering the page: After the JavaScript files are executed, Googlebot will render the page using the rendered HTML, CSS, and JavaScript.

Content is indexed: Once the page is rendered, Googlebot will index the page’s content as it would for a traditional website.

However, there are still some limitations to how Google crawls and indexes JavaScript-based websites. For example, Google bot may not execute certain types of JavaScript, such as those that use complex frameworks or libraries, which can result in some content being missed during the crawling and indexing process. In addition, Google bot may take longer to crawl and index JavaScript-based websites, as the process of rendering the page can be more resource-intensive than for traditional HTML-based websites.

To ensure that your JavaScript-based website is effectively crawled and indexed by Google, it’s essential to follow JavaScript SEO best practices, including using server-side rendering, optimizing metadata, and using lazy loading techniques. Additionally, website owners can use tools like Google Search Console to monitor how Google is crawling and indexing their website and identify any issues that may be affecting their search engine rankings.

Server-Side Rendering vs. Client-Side Rendering vs. Dynamic Rendering

Server-side rendering, client-side rendering, and dynamic rendering are all techniques used to render content on a web page. Here’s a brief overview of each technique:

Server-side rendering (SSR): With server-side rendering, the web server generates a fully rendered HTML page on the server and sends it to the client’s browser. The browser then displays the page as-is, without having to execute any JavaScript. SSR is generally faster than client-side rendering because the page is pre-rendered on the server, which can lead to better performance and improved search engine optimization (SEO).

Client-side rendering (CSR): With client-side rendering, the web server sends a bare-bones HTML page to the client’s browser, which then requests and executes JavaScript files to dynamically generate and render the page’s content. CSR can provide a more dynamic and interactive user experience than SSR, but it can also lead to slower page load times and issues with search engine indexing.

Dynamic rendering: Dynamic rendering involves serving up different versions of a web page depending on whether the user is a human visitor or a search engine crawler. For human visitors, the page can be rendered using client-side techniques, while search engines are served a pre-rendered version of the page using server-side rendering. This can improve page load times for human visitors while still ensuring that search engines can crawl and index the content.

Each rendering technique has its own advantages and disadvantages, and the choice of technique will depend on the specific needs and goals of a website. Server-side rendering is generally recommended for websites that need to maximize SEO and performance, while client-side rendering is better for websites that require a more dynamic and interactive user experience. Dynamic rendering can be a good compromise between the two, providing the best of both worlds.

Use Google Search Console to Find Errors

Googlebot is based on Chrome’s latest version. But it doesn’t behave the same way as a browser.

Which means launching your site doesn’t guarantee Google can render its content.

The URL Inspection Tool in Google Search Console (GSC) can check whether Google can render your pages.

Enter the URL of the page you want to test at the very top. And hit enter.

After a minute or two, the tool will show a “Live Test” tab. Now, click “View Tested Page,” and you’ll see the page’s code and a screenshot.

Check for any discrepancies or missing content by clicking on the “More Info” tab.

A common reason Google can’t render JS pages is because your site’s robots.txt file blocks the rendering. Often accidentally.

Add the following code to the robot.txt file to ensure no crucial resources are blocked from being crawled: