ভিইউই focus

<!DOCTYPE html>
<html>
<body>

<div id="app">

<input
  @focus="focused"
  placeholder="এখানে ক্লিক করুন">

</div>

<script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
<script>
Vue.createApp({
  methods: {
    focused(event) {
      event.target.style.background = "lightgreen";
    }
  }
}).mount("#app");
</script>

</body>
</html>