JavaScript is the programming language of the Web. Alongside HTML and CSS, JavaScript is one of the core technologies of the World Wide Web. JavaScript is dynamic, high-level, untyped interpreted language.

JavaScript has object oriented and functional features as well. JavaScript was created at Netscape. The programs written in JavaScript can run on browser. Today, a JavaScript code can be executed on server.

Core JavaScript provides support working with text, arrays, dates, DOM and regular expressions. Core JavaScript does not provide support for I/O, networking, storage or graphics. JavaScript depends on host environment for these features.

It may look like that JavaScript has resembles with Java but it is not the case. Both language are different in design and features.

Initially JavaScript was officially called LivScript. Since Java was a hot programming language at that time, it was renamed to JavaScript. JavaScript was developed by Brendan Eich.

Today, JavaScript can execute not only in the browser, but also on the server, or actually on any device which has JavaScript Engine installed.

The browser has an embedded engine sometimes called as “JavaScript virtual machine”.

Different engines are developed by different companies and have different “codenames”. Following are some of the popular JavaScript engines:

• V8 from Google. This JavaScript engine is used by Google Chrome and many other Chromium-based browsers. This JavaScript engine is also used by Node.js runtime system.
• SpiderMonkey developed by Mozilla and used in Firefox browser.
• JavaScriptCore from Apple and used in Safari browser.
• Chakra JavaScript engine is used in Internet Explorer browser.