js中(function(){…})()立即执行函数写法理解
http://blog.csdn.net/u010958922/article/details/47007589
https://zhidao.baidu.com/question/558917999?&oldq=1
http://blog.csdn.net/u010958922/article/details/47007589
https://zhidao.baidu.com/question/558917999?&oldq=1