1.代码

<script src="https://unpkg.com/vue@next" rel="external nofollow" ></script>
<div id="counter">
  Counter: {{ counter }}
</div>
<script>
const Counter = {
  data() {
    return {
      counter: 5
    }
  },
  mounted() {
    setInterval(() => {
      this.counter++
    }, 1000)
  }
}
Vue.createApp(Counter).mount('#counter')
</script>

2.运行结果