How Search Engines Render JavaScript Websites for SEO

 Along with HTML and CSS, the javascript programming language is one of the foundational elements of the World Wide Web. Moreover, a dedicated JavaScript engine is available in every major web browser and is used to run the code on users' devices.

Since JavaScript is an "interpreted" language. It decreases the time required for compilation in other programming languages like Java. 

JavaScript is also a client-side script that speeds up program execution by cutting down on time needed to establish a server connection.

However, every website needs SEO to rank high in SERP. So, making JavaScript-heavy websites simple to crawl and index while also being search-friendly is the goal of JavaScript SEO, a subset of Technical SEO.

How Google renders JavaScript websites?

Due to the use of JavaScript, many pages now need to be rendered by search engines like a browser would for them to display content to users.

Google processes JavaScript rendering in the following stages:

• Crawler

The crawler sends GET requests to the server. The server returns the headers and content of the file, which is then stored.

It is also crucial to remember that, despite Google's claim that the output of the crawling process is "HTML," they actually crawl and store all the resources required to create the page. It includes XHR requests, Javascript, CSS, API endpoints, HTML pages, and more.

• Processing

Google does not move between pages the way a person would. 

• Checking the page for links to other sites and files required to generate the page is a processing component.

• It aggressively caches every file that Google downloads, including HTML, CSS, JavaScript, etc.

• Before the downloaded HTML is transmitted for rendering, duplicate content will be removed or given lower priority.

• Between HTML and the displayed form of a page, Google will pick the most restrictive statements. If JavaScript modifies a statement that differs from the HTML statement, Google will follow the more restrictive statement.

• Rendering

Now, every page is sent to the renderer. Google renders a page in the renderer to see what a user sees.

A headless Chromium renders the page and runs the JavaScript when Google's resources permit. Googlebot parses the produced HTML for links and adds any it discovers to a crawl queue.

Google extensively uses caching resources. Therefore, everything is stored in a cache before transferring to the renderer. 

According to a prevalent SEO fallacy, the renderer only takes five seconds to load your page. This myth is not really supported by the way Google caches the content. The renderer does not have a set timeout.

However, keep in mind that not all bots can run JavaScript. Hence, server-side or prerender javascript SEO is a better option because it speeds up your website for users and crawlers.

Conclusion

The user experience has grown in importance, especially when creating apps compatible with various devices.

JavaScript shortens the code, which enhances the efficiency of web pages and web applications. As a result, all well-known organizations, such as Amazon, Google, PayPal, etc., employ JavaScript SEO.