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