说明：  jQuery 是一个JavaScript 库，它有助于简化 JavaScript™ 以及 Asynchronous JavaScript + XML (Ajax) 编程。与类似的 JavaScript 库不同，jQuery 具有独特的基本原理，可以简洁地表示常见的复杂代码。学习 jQuery 基本原理，探索其特性和功能，执行一些常见的 Ajax 任务并掌握如何使用插件扩展jQuery。jQuery 1.7 版本加入了新的事件API .on() 和 .off()，提高了性能，以及为旧版IE浏览器提供了更好的HTML5支持。
(JQuery is a JavaScript library, it is helpful to simplify the JavaScript and Asynchronous JavaScript+ XML (Ajax programming). Different similar JavaScript libraries, jQuery has a unique basic principle, which can be a concise representation of common complex code. Learn the basic principles of jQuery, explore its characteristics and functions, the implementation of some common Ajax tasks and master how to use the plug-in extension jQuery. JQuery version 1.7 added a new event.On API () and.Off (), to improve the performance, as well as the older version of the IE browser to provide better HTML5 support.)