JavaScript

A scripting language to enable Web page authors to design interactive sites. Although it shares many of the features and structures of the full Java language, it was developed independently. JavaScript can interact with HTML source code, enabling Web developers to jazz up their sites with dynamic content. For example, it makes it easy to respond to user-initiated events (such as form input) without having to use CGI.

JavaScript is endorsed by a number of software companies and is an open source language that anyone can use without purchasing a license. It is supported by recent versions of Netscape and Microsoft browsers, although the latter (Internet Explorer) only supports a subset that Microsoft calls Jscript.