(This book systematically introduces the basic syntax, basic objects, debugging tools and troubleshooting technology of JavaScript, event processing mechanism, browser object model / document object model (BOM / DOM), and goes deep into Ajax Application through a complex example. Explored. This book provides many easy to understand and themed examples, introduces a large number of best practices and good programming habits, and is of high value for improving code readability, maintainability and many cross browser compatibility problems. A detailed description is given to track the development of the new specification.This book is suitable for readers who want to add vitality to web pages / websites through JavaScript. Whether you have programming experience or not, you can quickly master this technology by reading this book. Before reading this book, you'd better have a good understanding of CSS and HTML / XHTML.)