今天所有引用 CDN 的网站都报这个错误，我终于知道原因了！！ [ 2.0 版本 ]

GET https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js net::ERR_BLOCKED_BY_CLIENT
(index):18 GET https://www.cdnjs.com/ net::ERR_CONNECTION_TIMED_OUT
layer.js?v=3111:2 Uncaught TypeError: i is not a function
    at Object.o.run (layer.js?v=3111:2)
    at layer.js?v=3111:2
    at layer.js?v=3111:2
    at layer.js?v=3111:2
o.run @ layer.js?v=3111:2
(anonymous) @ layer.js?v=3111:2
(anonymous) @ layer.js?v=3111:2
(anonymous) @ layer.js?v=3111:2
demo.js?v=20181117:6 Uncaught ReferenceError: $ is not defined
    at demo.js?v=20181117:6
    at demo.js?v=20181117:677
(anonymous) @ demo.js?v=20181117:6
(anonymous) @ demo.js?v=20181117:677
(index):581 Uncaught ReferenceError: jQuery is not defined
    at (index):581

是因为提供CDN这个 网站不停止服务了cdn.bootcss.com