Definition
JavaScript – often abbreviated as JS – is a scripting language that web developers can use to create interactive web pages. Along with HTML and CSS, JavaScript is one of the most widely used programming languages in web development.
In the past, JavaScript was mainly used for frontend development. However, it has also been used in backend development by frameworks like Node.js gained popularity.
An example of JavaScript files on our WDF-IDF tool page
What is JavaScript used for?
JavaScript is used for various applications on the Web, such as automatically updated news feeds, forms, search functions and other interactive functions. Almost all interactive functions that can be found on websites are created with JavaScript.
Since it is supported by all popular browsers, JS is widely used in frontend development. However, it is also used in other areas, such as mobile development, game development and backend development.
JavaScript libraries and frameworks
To make programming easier, there are numerous so-called JS libraries and frameworks. JavaScript libraries are used to be able to write codes for more complex functionalities faster. They allow developers to use ready-made code snippets and create and save their own code snippets for future use.
JavaScript frameworks are templates that specify a code structure, which can then be easily followed. This makes development easier on the one hand, but on the other hand there are restrictions that a developer must observe.
Examples of JS libraries are:
- jQuery
- ReactJS
- Dojo Toolkit
- Google Polymer
Examples of JS frameworks are:
- AngularJS
- Vue.BTT
- Apache Royale
If JavaScript is written without the use of libraries or frameworks, it is called “vanilla JavaScript”.
Client-side JavaScript vs. Server-side JavaScript
JavaScript can be used both client-side and server-side. Client-side JavaScript makes it possible to manipulate browsers and websites. It executes the script in the user’s browser and is one of the most common uses of JavaScript.
Server-side JavaScript does not run in the browser, but on the server. In general, it is less common than client-side JavaScript. An example of a popular server-side scripting framework for JavaScript is Node.BTT.
JavaScript and Search engines
Although JavaScript is an important programming language for web development, it is not always easy to process for search engines. If the JavaScript on a page is not optimized for search engine crawlers, there may be SEO problems.
This is especially true for sites that provide important content, links or other resources using JavaScript instead of HTML and CSS. This can lead to problems with crawling, as it may be that content is available for users, but not for search engine crawlers.
Google indexes and renders pages on the Web separately from each other, because running a script takes up more resources. For this reason, search engines like Google occasionally have difficulties with JavaScript.
Rendering takes more time and resources, which is why these two steps are split so that HTML and CSS are indexed faster. This means that the processing of JavaScript content can take longer, which means that indexing takes more time.
In recent years, major search engines like Google have become better at crawling and indexing JavaScript. Many smaller search engines or other crawlers, on the other hand, can still have problems loading JavaScript.
Some rendering methods can help crawlers process JavaScript, namely:
Server-side rendering
When JavaScript is rendered server-side instead of client-side, the fully rendered page is displayed to both users and crawlers. This can prevent many of the SEO problems that JavaScript can cause. However, it also takes up a lot of server resources.
Dynamic Rendering
Dynamic rendering allows server-side rendered resources to be sent to crawlers, while other users can render content on the client side. This will not only prevent SEO problems with crawling and indexing, but also an additional load on the server.
Hybrid Rendering
With hybrid rendering, the important resources are rendered on the server side and the less important content on the client side. This distributes the load between the client’s browser and the server, while the crawlers can immediately see the important content.
The importance of Web Development and SEO
JavaScript is one of the most important programming languages. It is very dynamic and is used in both frontend and backend web development.
Given the potential impact on SEO, as well as on the speed and performance of a page, it is important to understand how JavaScript works. Best practices can be used to learn how to program more effectively and improve the performance of a website.
