首先将我们已经用v-if控制显示与隐藏的盒子用

  <transition-group name="lyric"> </transition-group>标签包起来

name属性即为下面写样式的类名

<template>
<div>
<transition-group name="lyric">
//注意需要加入KEY值 否则报错
<div v-if="showDefaultAttr" :key="1">
</div>
</transition-group>
 <el-button @click="showDefaultAttr = !showDefaultAttr ">点击</el-button>
</div>
</template>
<script>
 data(){
    return{
    showDefaultAttr:false
        }
    }
</script>

然后再<style>中写上下面代码 

<style>
.lyric-enter,
  .lyric-leave-to {
  opacity: 0;
  transform: translateY(10px);
  }
  .lyric-enter-to,
  .lyric-leave {
  opacity: 1;

  }
  .lyric-enter-active,
  .lyric-leave-active {
  transition: all 0.5s;
  }
</style>