The most popular JavaScript frameworks and libraries

JavaScript (or JS for short) is a scripting language used to make HTML content interactive in the web browser. This language can be used for both object-orientated programming as well as procedural and functional programming. JavaScript contains predefined objects (i.e. data elements with special properties, methods, or functions) for accessing a web page, but they are sometimes cumbersome to use. To help users in writing JS, collected information has been made public. These instructions and tools come in the form of various JavaScript libraries and frameworks, with the aim to make programming easier. We will go through the best and most well-known tools below.

Library vs. framework

It’s important to keep the two terms separate. Often 'library' and 'framework' are used as synonyms even though this is wrong, strictly speaking. Even though the transition is seamless in many ways, there are basic differences between the two of them.

Library

A JavaScript library is a library of pre-written JavaScript that enables an easier development of JavaScript-based applications. Libraries always accommodate subprograms which, along with support functions, help with the programming process. In contrast to a framework, a library is more developed to one particular use, meaning it has functions that are coordinated to each other. For example, the JavaScript library D3.js is used for data visualization – with this library you can implement small tables, diagrams, and statistics, as well as more complex graphs (including animations and interactions). Libraries are always integrated by a software program: the program accesses the corresponding functions of a program library when they need a specific function. As a result, libraries can only work within a program and can’t run independently.

Framework

A framework is also not an autonomous program, but rather a special form of class library. A framework provides the software architecture (i.e. the basic structure) of an application and essentially determines the development process. Frameworks have certain design patterns with different functions (often in the form of many libraries) and are used to develop new, independent applications. An example is the Zend framework for PHP, which is used in Magento’s online store software and web analytics tool Piwik.

Inversion of Control (IoC)

Another difference between a framework and a library is how they are managed. With libraries, the code is accessed by programmers through a software program’s programming interface. Frameworks, however, carry out an inversion of control: the code is embedded in fixed structures and called up when needed. To summarize, you can say that libraries are called up by programs, whereas frameworks make specifications to the program.

JavaScript libraries and frameworks

The core of JavaScript is a rather simple programming language that lends itself particularly well for use within a browser. Many programmers face problems with their website interface, or DOM (Document Object Model). Here JavaScript frameworks and libraries come into play, making work a little bit easier for developers, regardless of their programming field. The JavaScript extensions introduced in the next section can all be downloaded for free.

Popular JavaScript libraries

JavaScript libraries are reusable codes through which certain features and functions for a website are assigned. jQuery is the most well-known JavaScript library and offers many useful features, although other libraries can be just as helpful.

jQuery

The very extensive jQuery library is the most-used JavaScript library. This is due to the fact that you can write simple cross-browser jQuery code, and that there are lots of plugins available for use. jQuery’s open source library is part of many content management systems like WordPress, Drupal, and Joomla!. jQuery also functions as an interface for DOM, offering some of the following functions:

  • Easy selection of website elements (similar to CSS3 selectors)
  • Possible to change selected website elements (such as position, color, etc.)
  • Event system: website elements react to user navigation (mouse clicks, keyboard input, etc.)
  • Easy implementation of animations and effects
  • Seamless interaction between user input and server data with Ajax requests (like with the autocomplete function) 

jQuery UI

jQuery UI is a free extension for jQuery. Its purpose is to define and implement a user interface (UI) from sources like websites or web apps. The focus here is on simple design and interactions. The functions jQuery has to offer include offering the possibility to implement interactive elements (e.g. drag and drop, zooming in and out), animations, effects, and widgets (like autocomplete, sliders, date picker, etc). The graphic editor, ThemeRoller, can be used to create original themes, or existing themes can be used to adapt for your own purposes. True to its simple design configuration, the modular structure of ThemeRoller allows only the necessary components need to be implemented.

Dojo Toolkit

The Dojo Toolkit is good for the implementation of web applications and dynamic web content. It comes with a variety of functions – the basic elements of the toolkit are:

  • Dojo (main program): quick and easy handling of DOM, Ajax, JavaScript, events, etc.
  • Dijit: a type of module for graphical user interface, widgets, layouts, effects, and animations (similar to jQuery UI).

React

React was first used in 2011 in Facebook’s newsfeed. It was then released on an open source basis in 2013. It is another JavaScript library with which you can create user interfaces. What sets this library apart from the rest is that the website elements (views) aren’t solely rendered on the client, but also on the server – which makes a more powerful rendering possible. This is due to the use of virtual DOMs, which also makes the testing of web applications easier.

Popular JavaScript frameworks

There are considerably more JavaScript libraries than frameworks. The latter are especially suitable for complex web applications. If developers embrace the concepts and specifications of respective frameworks, they will be able to work very efficiently with them. Two very extensive and frequently used tools are AngularJS and Ember.js.

AngularJS

This Google-maintained framework has by far the largest community among the JavaScript frameworks. AngularJS is used to create single page web applications (web apps, which consist only of HTML documents). Due to the MVVM (model-view-viewmodel) concept of this framework, web applications can be developed that are highly adaptable to user interaction. Here AngularJS renders the web application on the client side. The framework is based on jQuery Lite – a slimmed-down version of the well-known JavaScript library, jQuery.

Ember.js

Ember.js is also a client-side framework that is used for implementing single page web applications. Contrary to AngularJS, it is based on the MVC principle (Model View Controller). A further distinguishing feature is that the creators of Ember.js intensively involve the community in the framework’s development process; for instance, discussing significant framework changes with them before they are implemented. Ember.js is not for the faint of heart; creating web applications with this framework tends to be on the more ambitious side of things. As a result, it is primarily aimed at developers who already have experience with designing web applications.

Useful tools for many areas

Frameworks and libraries can considerably smooth the JavaScript programming process. Those mentioned above are only a small portion of the tools that are available. Additional resources for JavaScript frameworks, libraries, and plugins include GitHub and JavaScripting. Here you can find suitable JavaScript extensions for various purposes.