Dynamic HTML or DHTML is not any one specific technology. It is a group of technologies including HTML, JavaScript, VB Script, Document Object Model (DOM) and Cascading Style Sheets (CSS). JavaScript is a scripting language commonly used to build dynamic and interactive websites. JavaScript was developed by Brendan Eich in 1995, at Netscape Communications Corporation. JavaScript is a client-side scripting language, which means the source code is processed on client's web browser rather than on the web server. JavaScript is use to program the behavior of web pages. In HTML, JavaScript must be inserted between opening script tag and an closing script tag, and it can be put in the body or in the head section of an HTML page. JavaScript is the default scripting language in all modern browsers and it is a Case sensitive language. JavaScript is one of the 3 languages all web designer must learn: 1. HTML to define the content of web pages 2. CSS to specify the layout of web pages 3. JavaScript to program the behavior of web pages