<div id="app">
  <button @click="counterUp">
    Нажали - {{counter}}
  </button>
</div>
var app = new Vue({
 el: '#app',
 data:{
   counter:0
 },
  methods:{
    counterUp:function(){
      this.counter++;
    }
  }
 
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/vue/2.6.8/vue.min.js