JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
  <div>{{sum}}</div>
  <button type="submit" @click="add">더하기</button>
</div>

JavaScript

new Vue({
  el: '.container',
  data: {
    sum: 0
  },
  // 메서드는 methods 객체 아래 정의 합니다.
  methods: {
    add: function(event) {
      event.preventDefault();
      this.sum++;
    }
  }
});