javascript"><template>
  <div class="hello">
    我是哈蜜瓜
    <h1>{{ msg }}</h1>
  <div @click="counter">
    counter:  {{ counter }} 
  </div>
 
   
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  props: {
    msg: String
  },
  data() {
    return {
      counter: 0
    }
  },
  computed() {
    this.counter++
  }
}

</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h3 {
  margin: 40px 0 0;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>

正确

javascript"><template>
  <div class="hello">
    我是哈蜜瓜
    <h1>{{ msg }}</h1>
  <div @click="counter += 1">
    counter:  {{ counter }} 
  </div>
 
   
  </div>
</template>

<script>
export default {
  name: 'HelloWorld',
  props: {
    msg: String
  },
  data() {
    return {
      counter: 0
    }
  }
}

</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h3 {
  margin: 40px 0 0;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>