David Flanagan is a computer programmer who has spent much of the last 20 years writing books about programming languages. He now works at Mozilla. David lives with his wife and children in the Pacific Northwest, between the cities of Seattle and Vancouver.

JavaScript--the powerful, object-based scripting language that can be embedded directly into HTML pages--has earned its place in the web developer's toolkit, to the extent that it's now considered required knowledge for web developers. You can use JavaScript to create dynamic, interactive applications that run completely within a web browser. JavaScript is also the language of choice for developing Dynamic HTML content. Because its syntax is based on the popular programming languages C, C++, and Java, JavaScript is familiar and easy to learn for experienced programmers. At the same time, it's an interpreted scripting language, providing a flexible, forgiving programming environment for new programmers.