JavaScript is a very powerful client-side scripting language. JavaScript is used mainly for enhancing the interaction of a user with the webpage. In other words, you can make your webpage more lively and interactive, with the help of JavaScript. JavaScript is also being used widely in game development and Mobile application development.

Javascript History

JavaScript was developed by Brendan Eich in 1995, which appeared in Netscape, a popular browser of that time. The language was initially called LiveScript and was later renamed JavaScript. The syntax of JavaScript is mostly influenced by the programming language C.

How to run Javascript

Being a scripting language, JavaScript cannot run on its own. In fact, the browser is responsible for running JavaScript code. When a user requests an HTML page with JavaScript in it, the script is sent to the browser and it is up to the browser to execute it.

Tools to work with

You need a text editor to write your code and a browser to display the web pages you develop. You can use a text editor of your choice including Notepad++, Visual Studio Code, Sublime Text, Atom or any other text editor you are comfortable with. You can use any web browser including Google Chrome, Firefox, Microsoft Edge, Internet Explorer etc.

General language features

Scripting Language

JavaScript is a lightweight scripting language made for client-side execution on the browser. Since it is not designed as a general-purpose language and is specially engineered for web applications, the set of libraries is also geared primarily towards web applications.

Interpreter Based

JavaScript is an interpreted language instead of a compiled one. In that sense, it is closer to languages like Ruby and Python. The browser interprets JavaScript’s source code, line by line and runs it. In contrast, a compiled language needs to be compiled into a byte-code code executable.

Event Handling

An event is an action or an occurrence in a system that communicates about said occurrence so that you can respond to it somehow. For example, a user clicks on a button, and the system tells you to respond to the button click event with an action, say an information box.

JavaScript enables you to handle events and even generate custom events.

Light Weight

JavaScript isn’t a compiled language, so it doesn’t get converted to byte-code beforehand. However, it does follow a paradigm called Just-In-Time (JIT) Compilation. Meaning it gets converted to bytecode just as it’s about to run. This enables JS to be lightweight. Even less powerful devices are capable of running JavaScript.

Case Sensitive

JavaScript is highly case sensitive. All keywords, variables, functions names and other identifiers can and must only follow a consistent capitalisation of letters.