说明：  滚动监控器是Bootstrap提供的非常实用的JavaScript插件，被广泛应用到Web开发中。 插件源文件：scrollspy.js 官方发布引用地址：http://cdn.bootcss.com/bootstrap/2.3.1/js/bootstrap-scrollspy.js
(Scroll Monitor is provided very useful Bootstrap JavaScript plug-in, has been widely applied to Web development. Plug-in source file: scrollspy.js official release refers to the address: http: //cdn.bootcss.com/bootstrap/2.3.1/js/bootstrap-scrollspy.js)