点击 element el-checkbox-group复选框前面的框才能选中,点击后面的文字不让选中

<el-checkbox-group class="flex flex-col" v-model="checkedMessage">
  <el-checkbox @click="checkOnlyOnBox" class="margin-bottom-12 border-bottom" v-for="city in messageList" :key="city.key"
      :label="city.key" :alt="city.label">
      {{ city.label }}
  </el-checkbox>
</el-checkbox-group>

function checkOnlyOnBox(event: any){
  if("el-checkbox__inner" != event.target.className){
　　//点击的不是前面的小框框,阻止默认行为
    event.preventDefault();
  }else{
    //点击的是前面的小框框
  }
}