Post the information first, then organize it later
Learned: vaguely understandable.
http://blog.csdn.net/baidu_24024601/article/details/52710331
http://excellencenodejsblog.com/angularjs-directive-compile-pre-link-post-link-controller-functions/
Unlearned:
https://stackoverflow.com/questions/24615103/angular-directives-when-and-how-to-use-compile-controller-pre-link-and-post
https://stackoverflow.com/questions/12164138/what-is-the-difference-between-compile-and-link-function-in-angularjs
https://stackoverflow.com/questions/24615103/angular-directives-when-and-how-to-use-compile-controller-pre-link-and-post/24615239#24615239