In this digital world, business rolls around digital marketing. Every entrepreneur, startups and companies are learning the importance of digital marketing and wanted to invest more digital medium. Js & SEO are the two different topics but they come together in the search marketing. Previously, Search bots that include Google bots found difficult to understand Javascript. But, they can easily fetch and render the JS. It is important for an SEO to know how JS works with SEO and what are the things that they should keep their eye on. Here is a deep study on JS and how it works with SEO.

What is JavaScript?

Javascript is a programming language for the web which capable of update and changes both HTML and CSS. It is capable of calculating, manipulate and validate the data on a website. It is either embedded in HTML or linked/referenced.

What is AJAX?

AJAX stands for Asynchronous Javascript and XML. An AJAX is not programming languages and it can read the data from the web server, update the webpage and send data to the web server in the background. The AJAX uses XML HTTP object to request data from the web server. It makes use of Javascript and Html DOM to display the data. The XML HTTP object is created by Javascript to send a request to the server and when the server responds it will read and proper action is taken by Javascript.

What is DOM?

The DOM stands for document object model which is created to determine the structure of the page. The Dom Defines all the objects, properties, methods and events of HTML elements of the site. The DOM is created by parsing of information and resources from the HTML documents. Tip: When you inspect an element in a webpage then you can see DOM.

Headless browsing:

The headless browsing helps you to know how well your site works without UI. The headless browsers are used by testers to check the website. Even search engines use headless browsing to know more about a site or a mobile app.

key Factors Of Javascript in SEO:

  • Crawlability of the website by bots.
  • Bots ability to access your site content.
  • Critical path rendering.


The crawlability of the website determines how well a website is understood by the search engines. You can prevent crawlers from your site using robotic txt file, HTTP header status and robots meta tag.

Blocking JS:

The crawler helps search engines to index your site which indeed helps you in the ranking. Blocking javascript from the bots may result in cloaking as well as search engines can’t understand your site.

Internal linking:

The internal linking must be properly implemented with correct anchor texts using HTML or DOM. Using javascript on-click will affect link juices and navigation of the site. The interlinking is a strong signal for search engine and it can override canonical tags.

The Lone Slash:

The lone slash is not crawlable and using in the URL is not recommended by Google. Commonly, the slash is used to jump to a portion of the content.


The hash fragments are used to move in the static HTML document. There is no need for an HTTP request while using hash fragments. Escaped Fragment: The URL uses escaped fragment to indicate a jump in the content and also called ugly URL Original Experience: The URL has either # or ! to indicate escaped fragment in the page.

Pushstate History API:

The pushstate History API is a navigation based API which uses infinite scrolling without HTML request. The URL in the page is updated when the user scrolls down and it is supported by Google. In this page, the back button is used to move pages inside the site.


The search engines are using headless browsing to understand more about your site using DOM and Javascript of the site. Some important points on obtainability are given below.

  • The search engine may not see javascript after javascript load time that is 5s.
  • Search engines and browsers cannot find errors in the JS.
  • Providing Google with the same experience as the user helps your SEO.

How to Make sure Google Gets your Content?

  • Confirm your site content is visible on Dom as Google can experience both javascript and DOM.
  • Test a subset of the page to know whether Google can index your content (bullet testing).
  • Fetch as Google helps you to know whether your content is indexed.
  • Og tags and summary cards also help you to know about your meta content.

Html Snapshots:

The Html snapshots are nothing but a fully rendered page that can be sent to search engines. But, Html has provided with a chance of cloaking. Site Latency: The time taken by the site to load the content of the page which should be less than 5s. The critical render path is loading content which is necessary while the rest of the content after 5 seconds. Perceived Latency: When you have render blocking JS in your site then, it is called perceived latency. It takes more time to load a site than usual.

What To Do When You Have Render Blocking JS?

  • Adding JS in HTML document.
  • Adding async tag in the HTML attribute.
  • By placing JS lower within the HTML documents.

Conclusion: It is important for an SEO companies to learn about JS to increase the site speed as well as to provide a good user experience. By learning JS, one can improve the overall performance of the site and find errors in the site. I hope this article is useful to you. Thanks.