element 中表单验证的解析。

https://blog.csdn.net/qq_24504591/article/details/88048894

https://segmentfault.com/a/1190000012551362

https://www.jianshu.com/p/40854214b2c1

https://blog.csdn.net/xuaner8786/article/details/80361877

基本全部技术点都，待总结！