console 命令行工具 X clear
console
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8" />
  <title>t</title>
  <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>
<body>
  <div id="test">
     <p>{{ counter }}</p>
   <button v-on:click="increase(2,$event)">点击自增2</button>
  </div>
</body>
<script>
  var app1 = new Vue({
    el : '#test',
    data : {
      counter : 0
    },
    methods: {
      increase : function (step, event) {
      	this.counter += step
    	}
    }
  })
</script>
</html>