Importance of JavaScript Knowledge for SEO

Wilburn Montoya
Aug 3, 2018 · 3 min read
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Although the relation between SEO and JavaScript remains to be an unfinished debate, it is an agreed upon fact that the basic JavaScript knowledge is essential for the SEOs to better perform search engine optimization of the websites from technical perspectives.

Now, the major question that needs to be answered here is whether or not JavaScript is read well by search engines’ crawlers in order to evaluate the website’s content and analyze user experience.

Here, it would be worth mentioning that crawlers work directly on the portions of websites that are based on HTML, CSS and PHP. On the other hand, the JavaScript portions are not read directly by search engines’ crawlers. The crawlers first analyze the DOM and then they move to do rest of the task.

Some basic definitions

It would be worth defining a few helpful terms in this article.

First one to define is JavaScript. It is a programming language which tends to make the webpages interactive and dynamic. You can either put JavaScript into HTML or you can place a link to call the function.

The second term is HTML which stands for Hypertext Markup Language. If we define it simply, it can be regarded as a content organizer, i.e. it creates static structure of a webpage or website.

Another JavaScript function which is mostly used in the websites is AJAX which stands for Asynchronous JavaScript and XML. The basic purpose of this function is to update the content without refreshing the page.

There are a few things which you need to take into consideration.

Let the web crawlers access JavaScript in your pages

You can let web crawlers to get full opportunity to crawl pages of your website with the help of robot.txt. Blocking JavaScript in this file can lead the pages to appear differently to web crawlers as compared to how to appear to users. As a result, the search engines may consider this act as cloaking. Hence, you need to make sure that your pages are shown to search engine’s crawlers in the same manner as they are shown to the users.

Internal linking

Another strong SEO tool is internal linking of the website. With internal linking, you help search engine’s crawlers to know about the entire structure of your website. Here you have to make sure that you are not replacing internal linking with JavaScript on-click events. So, the best practice is to add links by making anchor tags in simple HTML or DOM.

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URL Structure

URLs that include lone hashes (#) are not recommended by Google even though they serve as identifiers within URLs. So, you can use the method of pushState History API which is used to update URL in the address bar while allowing JavaScript websites to leverage clean URLs.

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Site latency

After the creation of DOM of the received HTML document of a file, search engine loads majority of sources in the exact way as they are mentioned in HTML.

Now, if there is a massive file existent on the document, search engine is going to load this file before other elements. Now, it is worth mentioning that key idea of search engine is to load the information which is required by users. In majority of cases, this delay usually occurs due to a render-blocking JavaScript. Your website may have the ability to load faster but this latency is caused by JavaScript. There are a few ways you can reduce this latency. Those methods include:

Adding JavaScript in HTML

Using ‘async’ attribute to make JavaScript asynchronous

Reducing JavaScript elements within HTML

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