JavaScript gives you the freedom to add interactivity and responsiveness to your web pages.
The aim of this tutorial is to provide you with a thorough, yet accessible introduction to JavaScript using snappy explanations and practical tasks to try out right from the start.
No prior knowledge of JavaScript is assumed, but because JavaScript sits within and manipulates web pages, in order to be able to follow along, you should already be familiar with HTML and CSS. If you are new to either or both, you’re advised to step through our HTML and CSS tutorials first.
What is JavaScript
JavaScript is a cross-platform, object-oriented scripting language. It is a small and lightweight language. Inside a host environment (for example, a web browser), JavaScript can be connected to the objects of its environment to provide programmatic control over them.
JavaScript contains a standard library of objects, such as Array, Date, and Math, and a core set of language elements such as operators, control structures, and statements. Core JavaScript can be extended for a variety of purposes by supplementing it with additional objects; for example:
- Client-side JavaScript extends the core language by supplying objects to control a browser and its Document Object Model (DOM). For example, client-side extensions allow an application to place elements on an HTML form and respond to user events such as mouse clicks, form input, and page navigation.
- Server-side JavaScript extends the core language by supplying objects relevant to running JavaScript on a server. For example, server-side extensions allow an application to communicate with a database, provide continuity of information from one invocation to another of the application, or perform file manipulations on a server.
