import contents from './components/content';

  data() {
    return {
        test:'0'
    };
  },
  components:{
    'v-header':headers,
    'v-content':contents
  }

<v-content :childs='test'></v-content>

<template>
  <div @click="down()"></div>
</template>

methods: {
  down() {
    this.$emit('down','null'); //主动触发down方法，'null'为向父组件传递的数据
  }
}

<div>
  <child @down="changes" :test="test"></child> //监听子组件触发的down事件,然后调用changes方法
</div>
methods: {
  changes(msg) {
    this.test= test;
  }
}

//把a当作一个中转站
var a = new Vue();

<div @click="eve"></div>
methods:{
  eve(){
  a.$emit("change",'null')
 }
}

<div></div>
created(){
  a.$on('change',()=>{
    this.msg = 'null'
  })
}