vue中$refs、,$emit、$on
$emit
https://blog.csdn.net/sllailcp/article/details/78595077
$on
https://www.jianshu.com/p/a544728bf596
https://blog.csdn.net/chaochao466/article/details/82884966
// 这里需要强调的一点是:on和emit事件必须是在一个公共的实例上才能触发。
ref与$ref
$emit
https://blog.csdn.net/sllailcp/article/details/78595077
$on
https://www.jianshu.com/p/a544728bf596
https://blog.csdn.net/chaochao466/article/details/82884966