1)、开源项目免费 CDN 服务:http://www.bootcdn.cn/
   常用的列举:

https://cdn.bootcss.com/angular.js/1.5.0-beta.1/angular.js
https://cdn.bootcss.com/angular.js/1.5.0-beta.1/angular.min.js
https://cdn.bootcss.com/jquery/3.0.0-alpha1/jquery.js
https://cdn.bootcss.com/jquery/3.0.0-alpha1/jquery.min.js