JavaScript is a programming language mainly used for creating interactive web pages and web applications. It is one of the core technologies of the World Wide Web along with CSS and HTML. Javascript is the main scripting language used on the Website client-side. The scripts are embedded in HTML documents or attached as external files and they interact with the Document Object Model (DOM). The code is executed by a JavaScript engine that is built into the web browser. JavaScript enables complex features on a web page, like interactive content, animated graphics, maps, and loading new content without reloading the page.

JavaScript can also be used on the server-side of websites, in embedded systems, and in non-browser applications. For server-side scripting the main environment used for executing JavaScript code is Node.js. It also enables the use of JavaScript in embedded systems for programming devices like smartwatches and drones. To develop non-browser applications with behaviour implemented in JavaScript, software frameworks are used. For example, Electron is an open-source software framework that has been used to develop non-browser applications like Slack, Skype, and Microsoft Teams.