SEO Glossary: Javascript - All you need to know!

Table of contents


In a nutshell: What is Javascript?

JavaScript is a programming language that performs effects and certain applications. For example, rotating content that increases interactivity for users.

What is Javascript?

JavaScript (abbreviation JS) is a programming language or scripting language. It is integrated into the source code of a website and generates dynamic content in which, for example, graphics move or rotate.

JavaScript used to be known as LiveScript and first appeared in the Netscape browser in 1995.

Most commonly, a client-side JavaScript is used and embedded directly into HTML documents. This makes it possible to use JavaScript to add dynamic elements to otherwise static HTML. Here, for example, the website visitor can interact.

Free SEO Strategy Talk

In a free SEO strategy talk, we uncover untapped potential and develop a strategy to help you become more successful on Google.

Where is Javascript applied?

By now, JavaScript is used in many areas. Here are some examples:


  • A dynamic monthly calendar is displayed on a website, in which, for example, events of a company are entered.
  • When a user fills out a form, JavaScript checks the entries in the background and, if necessary, displays information such as "user name already taken".
  • In online stores, JavaScript is used to dynamically design a virtual shopping cart
  • In addition, webmasters can protect their images and text content from copying or hide the source code partially or completely
  • Furthermore, JavaScript can be provided with extensions. This involves creating an interface with other programming languages. The goal is to implement additional applications.


How is JavaScript included?

If website owners would like to include a JavaScript code, there are several variants to choose from:


  • Bei der Inline-Variante wird der JavaScript-Code zwischen zwei-<script>Elementen positioniert
  • If the JavaScript code is particularly large and complex, it can also be placed in an external file
  • Moreover, JavaScript can be a parameter of HTML code


Tip: When including JavaScript code in a website, it is extremely important that it does not output any errors. Because then it is a bug, which may have a negative effect on search engine optimization. Consequently, a ranking loss may occur.

What relation does JavaScript have to the search engine?

If a website visitor sees an interactive application generated by JavaScript, it is usually not recognized by a crawler. This is the reason why many search engines often ignore JavaScript.

The same applies to JavaScript applications that contain text. This is also ignored by crawlers, so there is no INDEXATION. For this reason, it is recommended to place important and relevant content such as text or images directly in the HTML code and not in the JavaScript.

In addition, also redirects should preferably not be done with JavaScript, but directly on the server.

I am one of the leading SEO experts in Germany

I am well known from major media out lets such as Stern, GoDaddy, Onpulson & the Breakfast TV and have made over 100+ big name clients successful on Google.

Conclusion on JavaScript

JavaScript is still a common scripting language and is used in many places. It is used, for example, to create dynamic and interactive content, to implement virtual calendars or to check form entries.

However, it should be noted that search engine crawlers from Google and Co. ignore JavaScript. Therefore, important contents like texts should be placed in the HTML code.


More glossary articles

Interesting blog articles

green TrustPilot logo
Trustpilot rating
Trust score: 4.9 - Ratings: 104
Best rated SEO agency 🏆
Google Logo
Google rating
Based on 228 reviews